Core Operations

These Operations form the core of Gaffer. They are always available.

Unless otherwise specified, this directed graph is used in the examples on this page:

graph TD
  1(1, count=3) -- count=3 --> 2
  1 -- count=1 --> 4
  2(2, count=1) -- count=2 --> 3
  2 -- count=1 --> 4(4, count=1)
  2 -- count=1 --> 5(5, count=3)
  3(3, count=2) -- count=4 --> 4

AddElements

Adds elements to a graph. Javadoc

Example adding a new entity and edge

Adding an additonal entity '6' and edge connecting it to '5'

JavaJSONPython

new AddElements.Builder()
            .input(new Entity.Builder()
                            .group("entity")
                            .vertex(6)
                            .property("count", 1)
                            .build(),
                    new Edge.Builder()
                            .group("edge")
                            .source(5).dest(6).directed(true)
                            .property("count", 1)
                            .build())
            .build();

{
  "class" : "AddElements",
  "input" : [ {
    "class" : "Entity",
    "group" : "entity",
    "vertex" : 6,
    "properties" : {
      "count" : 1
    }
  }, {
    "class" : "Edge",
    "group" : "edge",
    "source" : 5,
    "destination" : 6,
    "directed" : true,
    "properties" : {
      "count" : 1
    }
  } ],
  "skipInvalidElements" : false,
  "validate" : true
}

g.AddElements(
  input=[
    g.Entity(
      group="entity",
      properties={'count': 1},
      vertex=6
    ),
    g.Edge(
      group="edge",
      properties={'count': 1},
      source=5,
      destination=6,
      directed=True
    )
  ],
  skip_invalid_elements=False,
  validate=True
)

Results:

graph TD
  1 --> 2
  1 --> 4
  2 --> 3
  2 --> 4
  2 --> 5
  3 --> 4
  5 --> 6

DeleteElements

Deletes Elements from a graph. Javadoc

This operation will simply return a count of the number of elements deleted.

Warning

Deleting elements is not reversible. Use of this operation should be limited and users should run a test Operation Chain which extracts any elements to be deleted prior to running any delete operations.

Example deleting an entity and edge

Deleting entity '5' and its edge to entity '2'. A user can remove an entity and its associated edges by simply using a GetElements with an entity seed and no filtering.

JavaJSONPython

final OperationChain<Void> deleteElementsChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
            .input(new EntitySeed(5))
            .build())
        .then(new DeleteElements())
        .build();

graph.execute(deleteElementsChain, new User());

{
    "class" : "OperationChain",
    "operations" : [{
        "class": "GetElements",
        "input": [{
            "class": "EntitySeed",
            "vertex": 5,
        }]
    },
    {
        "class" : "DeleteElements"
    }]
}

g.OperationChain(
    operations=[
        g.GetElements(input=[g.EntitySeed(vertex=5)]),
        g.DeleteElements()
    ]
)

Graph following the removal of the entity and associated edges:

graph TD
  1 --> 2
  1 --> 4
  2 --> 3
  2 --> 4
  3 --> 4

Output:

    2

Example deleting only an edge

Using filtering, users can target a single edge and leave the associated entities from either end.

JavaJSONPython

final OperationChain<Void> deleteElementsChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
            .input(new EdgeSeed(2, 5, DirectedType.EITHER))
            .view(new View.Builder().edge("edge").build())
            .build())
        .then(new DeleteElements())
        .build();

graph.execute(deleteElementsChain, new User());

{
    "class" : "OperationChain",
    "operations" : [{
        "class": "GetElements",
        "input": [{
            "class": "EdgeSeed",
            "source": 2,
            "destination": 5,
            "directedType": "EITHER"
        }],
        "view": {
            "edges": {
                "edge": {}
            }
        }
    },
    {
        "class" : "DeleteElements"
    }]
}

g.OperationChain(
    operations=[
        g.GetElements(input=[g.EdgeSeed(source=2, destination=5, directedType="EITHER")],
        view = g.View(
            edges=[
                g.ElementDefinition(group="edge")
            ]
        )),
        g.DeleteElements()
    ]
)

Graph following the removal of a single edge, leaving all entities:

graph TD
  1 --> 2
  1 --> 4
  2 --> 3
  2 --> 4
  5
  3 --> 4

Output:

    1

Example deleting an entity

Deleting entity '5' but leaving all edges associated with it. This will leave 'dangling' or 'orphan' edges where there is no entity associated with the vertex on one end.

JavaJSONPython

final OperationChain<Void> deleteElementsChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
            .input(new EntitySeed(5))
            .view(new View.Builder().entity("person").build())
            .build())
        .then(new DeleteElements())
        .build();

graph.execute(deleteElementsChain, new User());

{
    "class" : "OperationChain",
    "operations" : [{
        "class": "GetElements",
        "input": [{
            "class": "EntitySeed",
            "vertex": 5,
        }],
        "view": {
            "entities": {
                "entity": {}
            }
        }
    },
    {
        "class" : "DeleteElements"
    }]
}

g.OperationChain(
    operations=[
        g.GetElements(
            input=[g.EntitySeed(vertex=5)],
            view = g.View(
                entities=[
                    g.ElementDefinition(
                        group="entity"
                    )
                ]
            )
        ),
        g.DeleteElements()
    ]
)

Graph following the removal of an entity. There will be the edge 2 --> 5 but it will only be a vertex:

graph TD
  1 --> 2
  1 --> 4
  2 --> 3
  2 --> 4
  2 --> 5(5, vertex-only)
  3 --> 4

Output:

    1

Aggregate

The Aggregate operation would normally be used in an Operation Chain to aggregate the results of a previous operation. Javadoc

Example simple aggregate elements

JavaJSONPython

final Aggregate aggregate = new Aggregate();

{
  "class" : "Aggregate"
}

g.Aggregate()

Example aggregate only edges of type edge with a transient property and provided aggregator

The groupBy has been set to an empty array. This will override the groupBy value in the schema.

JavaJSONPython

final String[] groupBy = {};
final Aggregate aggregate = new Aggregate.Builder()
        .edge("edge", new AggregatePair(
                groupBy,
                new ElementAggregator.Builder()
                        .select("transientProperty1")
                        .execute(new StringConcat())
                        .build()))
        .build();

{
  "class" : "Aggregate",
  "edges" : {
    "edge" : {
      "elementAggregator" : {
        "operators" : [ {
          "selection" : [ "transientProperty1" ],
          "binaryOperator" : {
            "class" : "StringConcat",
            "separator" : ","
          }
        } ]
      },
      "groupBy" : [ ]
    }
  }
}

g.Aggregate(
  edges=[
    g.AggregatePair(
      group="edge",
      group_by=[
      ],
      element_aggregator=g.ElementAggregateDefinition(
        operators=[
          g.BinaryOperatorContext(
            selection=[
              "transientProperty1"
            ],
            binary_operator=g.BinaryOperator(
              class_name="uk.gov.gchq.koryphe.impl.binaryoperator.StringConcat",
              fields={'separator': ','}
            )
          )
        ]
      )
    )
  ]
)

Count

Counts the number of items in an iterable. Javadoc

Example counting all elements

JavaJSONPython

OperationChain<Long> countAllElements = new OperationChain.Builder()
        .first(new GetAllElements())
        .then(new Count<>())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetAllElements"
  }, {
    "class" : "Count"
  } ]
}

g.OperationChain(
  operations=[
    g.GetAllElements(),
    g.Count()
  ]
)

Results:

JavaJSON

11

11

CountGroups

Counts the different element groups. Javadoc

Example counting all element groups

JavaJSONPython

final OperationChain<GroupCounts> opChain = new OperationChain.Builder()
        .first(new GetAllElements())
        .then(new CountGroups())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetAllElements"
  }, {
    "class" : "CountGroups"
  } ]
}

g.OperationChain(
  operations=[
    g.GetAllElements(),
    g.CountGroups()
  ]
)

Results:

JavaJSON

GroupCounts[entityGroups={entity=5},edgeGroups={edge=6},limitHit=false]

{
  "entityGroups" : {
    "entity" : 5
  },
  "edgeGroups" : {
    "edge" : 6
  },
  "limitHit" : false
}

Example counting all element groups with limit

JavaJSONPython

final OperationChain<GroupCounts> opChain = new OperationChain.Builder()
        .first(new GetAllElements())
        .then(new CountGroups(5))
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetAllElements"
  }, {
    "class" : "CountGroups",
    "limit" : 5
  } ]
}

g.OperationChain(
  operations=[
    g.GetAllElements(),
    g.CountGroups(
      limit=5
    )
  ]
)

Results:

JavaJSON

GroupCounts[entityGroups={entity=3},edgeGroups={edge=2},limitHit=true]

{
  "entityGroups" : {
    "entity" : 3
  },
  "edgeGroups" : {
    "edge" : 2
  },
  "limitHit" : true
}

Filter

Filters elements. Javadoc

Example filtering for elements with a count more than 2

The filter will only return elements (Entities and Edges) with a count more than 2. The results show the Edge between 1 & 4 that has a count of 1 has been removed.

JavaJSONPython

final OperationChain<Iterable<? extends Element>> opChain = new OperationChain.Builder()
        .first(new NamedOperation.Builder<EntitySeed, Iterable<? extends Element>>()
                .name("1-hop")
                .input(new EntitySeed(1))
                .build())
        .then(new Filter.Builder()
                .globalElements(new ElementFilter.Builder()
                        .select("count")
                        .execute(new IsMoreThan(2))
                        .build())
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "NamedOperation",
    "input" : [ {
      "class" : "EntitySeed",
      "class" : "EntitySeed",
      "vertex" : 1
    } ],
    "operationName" : "1-hop"
  }, {
    "class" : "Filter",
    "globalElements" : {
      "predicates" : [ {
        "selection" : [ "count" ],
        "predicate" : {
          "class" : "IsMoreThan",
          "orEqualTo" : false,
          "value" : 2
        }
      } ]
    }
  } ]
}

g.OperationChain(
  operations=[
    g.NamedOperation(
      input=[
        g.EntitySeed(
          vertex=1
        )
      ],
      operation_name="1-hop"
    ),
    g.Filter(
      global_elements=g.GlobalElementFilterDefinition(
        predicates=[
          g.PredicateContext(
            selection=[
              "count"
            ],
            predicate=g.IsMoreThan(
              value=2,
              or_equal_to=False
            )
          )
        ]
      )
    )
  ]
)

Results:

JavaJSON

Entity[vertex=1,group=entity,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=1,destination=2,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>3]]

[ {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 1,
  "properties" : {
    "count" : 3
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 2,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 3
  }
} ]

Example filtering for edges of type edge with count more than 2

Similar to the previous example but this will only return Edges with group 'edge' that have a count more than 2.

JavaJSONPython

final OperationChain<Iterable<? extends Element>> opChain = new OperationChain.Builder()
        .first(new NamedOperation.Builder<EntitySeed, Iterable<? extends Element>>()
                .name("1-hop")
                .input(new EntitySeed(1))
                .build())
        .then(new Filter.Builder()
                .edge("edge", new ElementFilter.Builder()
                        .select("count")
                        .execute(new IsMoreThan(2))
                        .build())
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "NamedOperation",
    "input" : [ {
      "class" : "EntitySeed",
      "class" : "EntitySeed",
      "vertex" : 1
    } ],
    "operationName" : "1-hop"
  }, {
    "class" : "Filter",
    "edges" : {
      "edge" : {
        "predicates" : [ {
          "selection" : [ "count" ],
          "predicate" : {
            "class" : "IsMoreThan",
            "orEqualTo" : false,
            "value" : 2
          }
        } ]
      }
    }
  } ]
}

g.OperationChain(
  operations=[
    g.NamedOperation(
      input=[
        g.EntitySeed(
          vertex=1
        )
      ],
      operation_name="1-hop"
    ),
    g.Filter(
      edges=[
        g.ElementFilterDefinition(
          group="edge",
          predicates=[
            g.PredicateContext(
              selection=[
                "count"
              ],
              predicate=g.IsMoreThan(
                value=2,
                or_equal_to=False
              )
            )
          ]
        )
      ]
    )
  ]
)

Results:

JavaJSON

Edge[source=1,destination=2,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>3]]

[ {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 2,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 3
  }
} ]

Limit

Limits the number of elements returned. This truncates output by default, but optionally an exception can be thrown instead of truncating. Javadoc

Example limiting elements to 3

JavaJSONPython

final OperationChain<Iterable<? extends Element>> opChain = new OperationChain.Builder()
        .first(new GetAllElements())
        .then(new Limit<>(3))
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetAllElements"
  }, {
    "class" : "Limit",
    "resultLimit" : 3,
    "truncate" : true
  } ]
}

g.OperationChain(
  operations=[
    g.GetAllElements(),
    g.Limit(
      result_limit=3,
      truncate=True
    )
  ]
)

Results:

JavaJSON

Edge[source=1,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=5,group=entity,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=3,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>4]]

[ {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 5,
  "properties" : {
    "count" : 3
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 3,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 4
  }
} ]

Example limiting elements to 3 without truncation

Setting this flag to false will throw an error instead of truncating the iterable. In this case there are more than 3 elements, so when executed a LimitExceededException would be thrown.

JavaJSONPython

final OperationChain<Iterable<? extends Element>> opChain = new OperationChain.Builder()
        .first(new GetAllElements())
        .then(new Limit<>(3, false))
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetAllElements"
  }, {
    "class" : "Limit",
    "resultLimit" : 3,
    "truncate" : false
  } ]
}

g.OperationChain(
  operations=[
    g.GetAllElements(),
    g.Limit(
      result_limit=3,
      truncate=False
    )
  ]
)

Example limiting elements to 3 with builder

A builder can also be used to create the limit - note that truncate is set to true by default, so in this case it is redundant, but simply shown for demonstration.

JavaJSONPython

final OperationChain<Iterable<? extends Element>> opChain = new OperationChain.Builder()
        .first(new GetAllElements())
        .then(new Limit.Builder<Element>()
                .resultLimit(3)
                .truncate(true)
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetAllElements"
  }, {
    "class" : "Limit",
    "resultLimit" : 3,
    "truncate" : true
  } ]
}

g.OperationChain(
  operations=[
    g.GetAllElements(),
    g.Limit(
      result_limit=3,
      truncate=True
    )
  ]
)

Results:

JavaJSON

Edge[source=1,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=5,group=entity,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=3,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>4]]

[ {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 5,
  "properties" : {
    "count" : 3
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 3,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 4
  }
} ]

Min

Extracts the minimum element based on provided Comparators. Javadoc

Example min count

JavaJSONPython

final OperationChain<Element> opChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new Min.Builder()
                .comparators(new ElementPropertyComparator.Builder()
                        .groups("entity", "edge")
                        .property("count")
                        .build())
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ]
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.compare.Min",
    "comparators" : [ {
      "class" : "ElementPropertyComparator",
      "property" : "count",
      "groups" : [ "entity", "edge" ],
      "reversed" : false
    } ]
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.Min(
      comparators=[
        g.ElementPropertyComparator(
          groups=[
            "entity",
            "edge"
          ],
          property="count",
          reversed=False
        )
      ]
    )
  ]
)

Results:

JavaJSON

Edge[source=1,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]

{
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}

Example min count and transient property

JavaJSONPython

final OperationChain<Element> opChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .view(new View.Builder()
                        .entity("entity", new ViewElementDefinition.Builder()
                                .transientProperty("score", Integer.class)
                                .transformer(new ElementTransformer.Builder()
                                        .select("VERTEX", "count")
                                        .execute(new ExampleScoreFunction())
                                        .project("score")
                                        .build())
                                .build())
                        .edge("edge", new ViewElementDefinition.Builder()
                                .transientProperty("score", Integer.class)
                                .transformer(new ElementTransformer.Builder()
                                        .select("DESTINATION", "count")
                                        .execute(new ExampleScoreFunction())
                                        .project("score")
                                        .build())
                                .build())
                        .build())
                .build())
        .then(new Min.Builder()
                .comparators(
                        new ElementPropertyComparator.Builder()
                                .groups("entity", "edge")
                                .property("count")
                                .reverse(false)
                                .build(),
                        new ElementPropertyComparator.Builder()
                                .groups("entity", "edge")
                                .property("score")
                                .reverse(false)
                                .build()
                )
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ],
    "view" : {
      "edges" : {
        "edge" : {
          "transientProperties" : {
            "score" : "Integer"
          },
          "transformFunctions" : [ {
            "selection" : [ "DESTINATION", "count" ],
            "function" : {
              "class" : "ExampleScoreFunction"
            },
            "projection" : [ "score" ]
          } ]
        }
      },
      "entities" : {
        "entity" : {
          "transientProperties" : {
            "score" : "Integer"
          },
          "transformFunctions" : [ {
            "selection" : [ "VERTEX", "count" ],
            "function" : {
              "class" : "ExampleScoreFunction"
            },
            "projection" : [ "score" ]
          } ]
        }
      }
    }
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.compare.Min",
    "comparators" : [ {
      "class" : "ElementPropertyComparator",
      "property" : "count",
      "groups" : [ "entity", "edge" ],
      "reversed" : false
    }, {
      "class" : "ElementPropertyComparator",
      "property" : "score",
      "groups" : [ "entity", "edge" ],
      "reversed" : false
    } ]
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      view=g.View(
        entities=[
          g.ElementDefinition(
            group="entity",
            transient_properties={'score': 'java.lang.Integer'},
            transform_functions=[
              g.FunctionContext(
                selection=[
                  "VERTEX",
                  "count"
                ],
                function=g.Function(
                  class_name="uk.gov.gchq.gaffer.doc.operation.function.ExampleScoreFunction",
                  fields={}
                ),
                projection=[
                  "score"
                ]
              )
            ]
          )
        ],
        edges=[
          g.ElementDefinition(
            group="edge",
            transient_properties={'score': 'java.lang.Integer'},
            transform_functions=[
              g.FunctionContext(
                selection=[
                  "DESTINATION",
                  "count"
                ],
                function=g.Function(
                  class_name="uk.gov.gchq.gaffer.doc.operation.function.ExampleScoreFunction",
                  fields={}
                ),
                projection=[
                  "score"
                ]
              )
            ]
          )
        ],
        all_edges=False,
        all_entities=False
      ),
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.Min(
      comparators=[
        g.ElementPropertyComparator(
          groups=[
            "entity",
            "edge"
          ],
          property="count",
          reversed=False
        ),
        g.ElementPropertyComparator(
          groups=[
            "entity",
            "edge"
          ],
          property="score",
          reversed=False
        )
      ]
    )
  ]
)

Results:

JavaJSON

Entity[vertex=2,group=entity,properties=Properties[score=<java.lang.Integer>2,count=<java.lang.Integer>1]]

{
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 2,
  "properties" : {
    "score" : 2,
    "count" : 1
  }
}

Max

Extracts the maximum element based on provided Comparators. Javadoc

Example max count

JavaJSONPython

final OperationChain<Element> opChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new Max.Builder()
                .comparators(new ElementPropertyComparator.Builder()
                        .groups("entity", "edge")
                        .property("count")
                        .build())
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ]
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.compare.Max",
    "comparators" : [ {
      "class" : "ElementPropertyComparator",
      "property" : "count",
      "groups" : [ "entity", "edge" ],
      "reversed" : false
    } ]
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.Max(
      comparators=[
        g.ElementPropertyComparator(
          groups=[
            "entity",
            "edge"
          ],
          property="count",
          reversed=False
        )
      ]
    )
  ]
)

Results:

JavaJSON

Entity[vertex=1,group=entity,properties=Properties[count=<java.lang.Integer>3]]

{
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 1,
  "properties" : {
    "count" : 3
  }
}

Example max count and transient property

JavaJSONPython

final OperationChain<Element> opChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .view(new View.Builder()
                        .entity("entity", new ViewElementDefinition.Builder()
                                .transientProperty("score", Integer.class)
                                .transformer(new ElementTransformer.Builder()
                                        .select("VERTEX", "count")
                                        .execute(new ExampleScoreFunction())
                                        .project("score")
                                        .build())
                                .build())
                        .edge("edge", new ViewElementDefinition.Builder()
                                .transientProperty("score", Integer.class)
                                .transformer(new ElementTransformer.Builder()
                                        .select("DESTINATION", "count")
                                        .execute(new ExampleScoreFunction())
                                        .project("score")
                                        .build())
                                .build())
                        .build())
                .build())
        .then(new Max.Builder()
                .comparators(
                        new ElementPropertyComparator.Builder()
                                .groups("entity", "edge")
                                .property("count")
                                .reverse(false)
                                .build(),
                        new ElementPropertyComparator.Builder()
                                .groups("entity", "edge")
                                .property("score")
                                .reverse(false)
                                .build()
                )
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ],
    "view" : {
      "edges" : {
        "edge" : {
          "transientProperties" : {
            "score" : "Integer"
          },
          "transformFunctions" : [ {
            "selection" : [ "DESTINATION", "count" ],
            "function" : {
              "class" : "ExampleScoreFunction"
            },
            "projection" : [ "score" ]
          } ]
        }
      },
      "entities" : {
        "entity" : {
          "transientProperties" : {
            "score" : "Integer"
          },
          "transformFunctions" : [ {
            "selection" : [ "VERTEX", "count" ],
            "function" : {
              "class" : "ExampleScoreFunction"
            },
            "projection" : [ "score" ]
          } ]
        }
      }
    }
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.compare.Max",
    "comparators" : [ {
      "class" : "ElementPropertyComparator",
      "property" : "count",
      "groups" : [ "entity", "edge" ],
      "reversed" : false
    }, {
      "class" : "ElementPropertyComparator",
      "property" : "score",
      "groups" : [ "entity", "edge" ],
      "reversed" : false
    } ]
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      view=g.View(
        entities=[
          g.ElementDefinition(
            group="entity",
            transient_properties={'score': 'java.lang.Integer'},
            transform_functions=[
              g.FunctionContext(
                selection=[
                  "VERTEX",
                  "count"
                ],
                function=g.Function(
                  class_name="uk.gov.gchq.gaffer.doc.operation.function.ExampleScoreFunction",
                  fields={}
                ),
                projection=[
                  "score"
                ]
              )
            ]
          )
        ],
        edges=[
          g.ElementDefinition(
            group="edge",
            transient_properties={'score': 'java.lang.Integer'},
            transform_functions=[
              g.FunctionContext(
                selection=[
                  "DESTINATION",
                  "count"
                ],
                function=g.Function(
                  class_name="uk.gov.gchq.gaffer.doc.operation.function.ExampleScoreFunction",
                  fields={}
                ),
                projection=[
                  "score"
                ]
              )
            ]
          )
        ],
        all_edges=False,
        all_entities=False
      ),
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.Max(
      comparators=[
        g.ElementPropertyComparator(
          groups=[
            "entity",
            "edge"
          ],
          property="count",
          reversed=False
        ),
        g.ElementPropertyComparator(
          groups=[
            "entity",
            "edge"
          ],
          property="score",
          reversed=False
        )
      ]
    )
  ]
)

Results:

JavaJSON

Edge[source=1,destination=2,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[score=<java.lang.Integer>6,count=<java.lang.Integer>3]]

{
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 2,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "score" : 6,
    "count" : 3
  }
}

Sort

Sorts elements based on provided Comparators and can be used to extract the top 'n' elements. Javadoc

Example sorting on count

JavaJSONPython

final OperationChain<Iterable<? extends Element>> opChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new Sort.Builder()
                .comparators(new ElementPropertyComparator.Builder()
                        .groups("entity", "edge")
                        .property("count")
                        .reverse(false)
                        .build())
                .resultLimit(10)
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ]
  }, {
    "class" : "Sort",
    "comparators" : [ {
      "class" : "ElementPropertyComparator",
      "property" : "count",
      "groups" : [ "entity", "edge" ],
      "reversed" : false
    } ],
    "deduplicate" : true,
    "resultLimit" : 10
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.Sort(
      comparators=[
        g.ElementPropertyComparator(
          groups=[
            "entity",
            "edge"
          ],
          property="count",
          reversed=False
        )
      ],
      result_limit=10,
      deduplicate=True
    )
  ]
)

Results:

JavaJSON

Edge[source=2,destination=5,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Edge[source=2,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=2,group=entity,properties=Properties[count=<java.lang.Integer>1]]
Edge[source=1,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Edge[source=2,destination=3,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>2]]
Entity[vertex=1,group=entity,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=1,destination=2,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>3]]

[ {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 5,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 2,
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 3,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 2
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 1,
  "properties" : {
    "count" : 3
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 2,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 3
  }
} ]

Example sorting on count without deduplicating

Deduplication is true by default.

JavaJSONPython

final OperationChain<Iterable<? extends Element>> opChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new Sort.Builder()
                .comparators(new ElementPropertyComparator.Builder()
                        .groups("entity", "edge")
                        .property("count")
                        .reverse(false)
                        .build())
                .resultLimit(10)
                .deduplicate(false)
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ]
  }, {
    "class" : "Sort",
    "comparators" : [ {
      "class" : "ElementPropertyComparator",
      "property" : "count",
      "groups" : [ "entity", "edge" ],
      "reversed" : false
    } ],
    "deduplicate" : false,
    "resultLimit" : 10
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.Sort(
      comparators=[
        g.ElementPropertyComparator(
          groups=[
            "entity",
            "edge"
          ],
          property="count",
          reversed=False
        )
      ],
      result_limit=10,
      deduplicate=False
    )
  ]
)

Results:

JavaJSON

Edge[source=1,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=2,group=entity,properties=Properties[count=<java.lang.Integer>1]]
Edge[source=2,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Edge[source=2,destination=5,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Edge[source=2,destination=3,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>2]]
Entity[vertex=1,group=entity,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=1,destination=2,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>3]]

[ {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 2,
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 5,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 3,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 2
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 1,
  "properties" : {
    "count" : 3
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 2,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 3
  }
} ]

Example sorting on count and transient property

JavaJSONPython

final OperationChain<Iterable<? extends Element>> opChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .view(new View.Builder()
                        .entity("entity", new ViewElementDefinition.Builder()
                                .transientProperty("score", Integer.class)
                                .transformer(new ElementTransformer.Builder()
                                        .select("VERTEX", "count")
                                        .execute(new ExampleScoreFunction())
                                        .project("score")
                                        .build())
                                .build())
                        .edge("edge", new ViewElementDefinition.Builder()
                                .transientProperty("score", Integer.class)
                                .transformer(new ElementTransformer.Builder()
                                        .select("DESTINATION", "count")
                                        .execute(new ExampleScoreFunction())
                                        .project("score")
                                        .build())
                                .build())
                        .build())
                .build())
        .then(new Sort.Builder()
                .comparators(
                        new ElementPropertyComparator.Builder()
                                .groups("entity", "edge")
                                .property("count")
                                .reverse(false)
                                .build(),
                        new ElementPropertyComparator.Builder()
                                .groups("entity", "edge")
                                .property("score")
                                .reverse(false)
                                .build()
                )
                .resultLimit(4)
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ],
    "view" : {
      "edges" : {
        "edge" : {
          "transientProperties" : {
            "score" : "Integer"
          },
          "transformFunctions" : [ {
            "selection" : [ "DESTINATION", "count" ],
            "function" : {
              "class" : "ExampleScoreFunction"
            },
            "projection" : [ "score" ]
          } ]
        }
      },
      "entities" : {
        "entity" : {
          "transientProperties" : {
            "score" : "Integer"
          },
          "transformFunctions" : [ {
            "selection" : [ "VERTEX", "count" ],
            "function" : {
              "class" : "ExampleScoreFunction"
            },
            "projection" : [ "score" ]
          } ]
        }
      }
    }
  }, {
    "class" : "Sort",
    "comparators" : [ {
      "class" : "ElementPropertyComparator",
      "property" : "count",
      "groups" : [ "entity", "edge" ],
      "reversed" : false
    }, {
      "class" : "ElementPropertyComparator",
      "property" : "score",
      "groups" : [ "entity", "edge" ],
      "reversed" : false
    } ],
    "deduplicate" : true,
    "resultLimit" : 4
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      view=g.View(
        entities=[
          g.ElementDefinition(
            group="entity",
            transient_properties={'score': 'java.lang.Integer'},
            transform_functions=[
              g.FunctionContext(
                selection=[
                  "VERTEX",
                  "count"
                ],
                function=g.Function(
                  class_name="uk.gov.gchq.gaffer.doc.operation.function.ExampleScoreFunction",
                  fields={}
                ),
                projection=[
                  "score"
                ]
              )
            ]
          )
        ],
        edges=[
          g.ElementDefinition(
            group="edge",
            transient_properties={'score': 'java.lang.Integer'},
            transform_functions=[
              g.FunctionContext(
                selection=[
                  "DESTINATION",
                  "count"
                ],
                function=g.Function(
                  class_name="uk.gov.gchq.gaffer.doc.operation.function.ExampleScoreFunction",
                  fields={}
                ),
                projection=[
                  "score"
                ]
              )
            ]
          )
        ],
        all_edges=False,
        all_entities=False
      ),
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.Sort(
      comparators=[
        g.ElementPropertyComparator(
          groups=[
            "entity",
            "edge"
          ],
          property="count",
          reversed=False
        ),
        g.ElementPropertyComparator(
          groups=[
            "entity",
            "edge"
          ],
          property="score",
          reversed=False
        )
      ],
      result_limit=4,
      deduplicate=True
    )
  ]
)

Results:

JavaJSON

Entity[vertex=2,group=entity,properties=Properties[score=<java.lang.Integer>2,count=<java.lang.Integer>1]]
Edge[source=1,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[score=<java.lang.Integer>4,count=<java.lang.Integer>1]]
Edge[source=2,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[score=<java.lang.Integer>4,count=<java.lang.Integer>1]]
Edge[source=2,destination=5,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[score=<java.lang.Integer>5,count=<java.lang.Integer>1]]

[ {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 2,
  "properties" : {
    "score" : 2,
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "score" : 4,
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "score" : 4,
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 5,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "score" : 5,
    "count" : 1
  }
} ]

Reduce

Reduces an input to an output with a single value using provided function. Javadoc

Example of reduce

JavaJSONPython

final OperationChain<Iterable<?>> opChain = new OperationChain.Builder()
        .first(new GetAdjacentIds.Builder()
                .input(new EntitySeed(1))
                .build())
        .then(new ForEach.Builder<>()
                .operation(new OperationChain.Builder()
                        .first(new ToSingletonList<EntitySeed>())
                        .then(new GetAdjacentIds())
                        .then(new ToVertices())
                        .then(new Reduce.Builder<>()
                                .aggregateFunction(new Sum())
                                .build())
                        .build())
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetAdjacentIds",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    } ]
  }, {
    "class" : "ForEach",
    "operation" : {
      "class" : "OperationChain",
      "operations" : [ {
        "class" : "ToSingletonList"
      }, {
        "class" : "GetAdjacentIds"
      }, {
        "class" : "ToVertices"
      }, {
        "class" : "Reduce",
        "aggregateFunction" : {
          "class" : "Sum"
        }
      } ]
    }
  } ]
}

g.OperationChain(
  operations=[
    g.GetAdjacentIds(
      input=[
        g.EntitySeed(
          vertex=1
        )
      ]
    ),
    g.ForEach(
      operation=g.OperationChain(
        operations=[
          g.ToSingletonList(),
          g.GetAdjacentIds(),
          g.ToVertices(),
          g.Reduce(
            aggregate_function=g.Sum()
          )
        ]
      )
    )
  ]
)

Results:

JavaJSON

6
13

[ 6, 13 ]

Map

Maps an input to an output using provided functions. Javadoc

Example extracting from get elements

This simple example demonstrates retrieving elements from the "entity" group, from which the first item is extracted.

JavaJSONPython

final OperationChain<?> operationChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .view(new View.Builder()
                        .entity("entity")
                        .build())
                .build())
        .then(new Map.Builder<Iterable<? extends Element>>()
                .first(new FirstItem<>())
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ],
    "view" : {
      "entities" : {
        "entity" : { }
      }
    }
  }, {
    "class" : "Map",
    "functions" : [ {
      "class" : "FirstItem"
    } ]
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      view=g.View(
        entities=[
          g.ElementDefinition(
            group="entity"
          )
        ],
        all_edges=False,
        all_entities=False
      ),
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.Map(
      functions=[
        g.FirstItem()
      ]
    )
  ]
)

Results:

JavaJSON

Entity[vertex=2,group=entity,properties=Properties[count=<java.lang.Integer>1]]

{
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 2,
  "properties" : {
    "count" : 1
  }
}

Example extracting first items from walks

This example demonstrates the extraction of the input seeds to a GetWalks operation, using the Map operation with ExtractWalkEdgesFromHop, and FirstItem functions.

JavaJSONPython

final OperationChain<Set<?>> opChain = new OperationChain.Builder()
        .first(new GetWalks.Builder()
                .operations(new GetElements.Builder()
                        .view(new View.Builder()
                                .edge("edge")
                                .build())
                        .build())
                .resultsLimit(100)
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new Map.Builder<Iterable<Walk>>()
                .first(new IterableFunction.Builder<Walk>()
                        .first(new ExtractWalkEdgesFromHop(0))
                        .then(new FirstItem<>())
                        .build())
                .build())
        .then(new ToVertices.Builder()
                .edgeVertices(ToVertices.EdgeVertices.SOURCE)
                .build())
        .then(new ToSet<>())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetWalks",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ],
    "operations" : [ {
      "class" : "OperationChain",
      "operations" : [ {
        "class" : "GetElements",
        "view" : {
          "edges" : {
            "edge" : { }
          }
        }
      } ]
    } ],
    "resultsLimit" : 100
  }, {
    "class" : "Map",
    "functions" : [ {
      "class" : "IterableFunction",
      "functions" : [ {
        "class" : "ExtractWalkEdgesFromHop",
        "hop" : 0
      }, {
        "class" : "FirstItem"
      } ]
    } ]
  }, {
    "class" : "ToVertices",
    "edgeVertices" : "SOURCE"
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.output.ToSet"
  } ]
}

g.OperationChain(
  operations=[
    g.GetWalks(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ],
      operations=[
        g.OperationChain(
          operations=[
            g.GetElements(
              view=g.View(
                edges=[
                  g.ElementDefinition(
                    group="edge"
                  )
                ],
                all_edges=False,
                all_entities=False
              )
            )
          ]
        )
      ],
      results_limit=100
    ),
    g.Map(
      functions=[
        g.IterableFunction(
          functions=[
            g.ExtractWalkEdgesFromHop(
              hop=0
            ),
            g.FirstItem()
          ]
        )
      ]
    ),
    g.ToVertices(
      edge_vertices="SOURCE"
    ),
    g.ToSet()
  ]
)

Results:

JavaJSON

1
2

[ 1, 2 ]

Transform

The Transform operation would normally be used in an Operation Chain to transform the results of a previous operation. Javadoc

Example transforming count property into count string property only for edges of type edge

JavaJSONPython

final Transform transform = new Transform.Builder()
        .edge("edge", new ElementTransformer.Builder()
                .select("count")
                .execute(new ToString())
                .project("countString")
                .build())
        .build();

{
  "class" : "Transform",
  "edges" : {
    "edge" : {
      "functions" : [ {
        "selection" : [ "count" ],
        "function" : {
          "class" : "ToString"
        },
        "projection" : [ "countString" ]
      } ]
    }
  }
}

g.Transform(
  edges=[
    g.ElementTransformDefinition(
      group="edge",
      functions=[
        g.FunctionContext(
          selection=[
            "count"
          ],
          function=g.ToString(),
          projection=[
            "countString"
          ]
        )
      ]
    )
  ]
)

ToArray

Converts elements to Array. Javadoc

Note

Conversion into an Array is done in memory, so it is not advised for a large number of results.

Example ToArray

JavaJSONPython

final OperationChain<? extends Element[]> opChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new ToArray<>())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ]
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.output.ToArray"
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.ToArray()
  ]
)

Results:

JavaJSON

Edge[source=1,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=2,group=entity,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=1,group=entity,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=2,destination=3,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>2]]
Edge[source=2,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Edge[source=1,destination=2,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=2,destination=5,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]

[ {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 2,
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 1,
  "properties" : {
    "count" : 3
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 3,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 2
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 2,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 3
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 5,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
} ]

ToCsv

Converts elements to CSV Strings. Javadoc

Example ToCsv

JavaJSONPython

final OperationChain<Iterable<? extends String>> opChain = new Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new ToCsv.Builder()
                .includeHeader(true)
                .generator(new CsvGenerator.Builder()
                        .group("Edge group")
                        .vertex("vertex")
                        .source("source")
                        .property("count", "total count")
                        .build())
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ]
  }, {
    "class" : "ToCsv",
    "elementGenerator" : {
      "class" : "CsvGenerator",
      "fields" : {
        "GROUP" : "Edge group",
        "VERTEX" : "vertex",
        "SOURCE" : "source",
        "count" : "total count"
      },
      "constants" : { },
      "quoted" : false,
      "commaReplacement" : " "
    },
    "includeHeader" : true
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.ToCsv(
      element_generator=g.CsvGenerator(
        fields={'GROUP': 'Edge group', 'VERTEX': 'vertex', 'SOURCE': 'source', 'count': 'total count'},
        constants={},
        quoted=False,
        comma_replacement=" "
      ),
      include_header=True
    )
  ]
)

Results:

JavaJSON

Edge group,vertex,source,total count
edge,,1,1
entity,2,,1
entity,1,,3
edge,,2,2
edge,,2,1
edge,,1,3
edge,,2,1

[ "Edge group,vertex,source,total count", "edge,,1,1", "entity,2,,1", "entity,1,,3", "edge,,2,2", "edge,,2,1", "edge,,1,3", "edge,,2,1" ]

ToEntitySeeds

Converts object(s) into EntitySeeds. Javadoc

Example ToEntitySeeds

JavaJSONPython

final OperationChain<Iterable<? extends EntitySeed>> opChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new ToEntitySeeds())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ]
  }, {
    "class" : "ToEntitySeeds"
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.ToEntitySeeds()
  ]
)

Results:

JavaJSON

EntitySeed[vertex=Edge[source=1,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]]
EntitySeed[vertex=Entity[vertex=2,group=entity,properties=Properties[count=<java.lang.Integer>1]]]
EntitySeed[vertex=Entity[vertex=1,group=entity,properties=Properties[count=<java.lang.Integer>3]]]
EntitySeed[vertex=Edge[source=2,destination=3,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>2]]]
EntitySeed[vertex=Edge[source=2,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]]
EntitySeed[vertex=Edge[source=1,destination=2,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>3]]]
EntitySeed[vertex=Edge[source=2,destination=5,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]]

[ {
  "class" : "uk.gov.gchq.gaffer.operation.data.EntitySeed",
  "vertex" : {
    "uk.gov.gchq.gaffer.data.element.Edge" : {
      "class" : "uk.gov.gchq.gaffer.data.element.Edge",
      "group" : "edge",
      "source" : 1,
      "destination" : 4,
      "directed" : true,
      "matchedVertex" : "SOURCE",
      "properties" : {
        "count" : 1
      }
    }
  }
}, {
  "class" : "uk.gov.gchq.gaffer.operation.data.EntitySeed",
  "vertex" : {
    "uk.gov.gchq.gaffer.data.element.Entity" : {
      "class" : "uk.gov.gchq.gaffer.data.element.Entity",
      "group" : "entity",
      "vertex" : 2,
      "properties" : {
        "count" : 1
      }
    }
  }
}, {
  "class" : "uk.gov.gchq.gaffer.operation.data.EntitySeed",
  "vertex" : {
    "uk.gov.gchq.gaffer.data.element.Entity" : {
      "class" : "uk.gov.gchq.gaffer.data.element.Entity",
      "group" : "entity",
      "vertex" : 1,
      "properties" : {
        "count" : 3
      }
    }
  }
}, {
  "class" : "uk.gov.gchq.gaffer.operation.data.EntitySeed",
  "vertex" : {
    "uk.gov.gchq.gaffer.data.element.Edge" : {
      "class" : "uk.gov.gchq.gaffer.data.element.Edge",
      "group" : "edge",
      "source" : 2,
      "destination" : 3,
      "directed" : true,
      "matchedVertex" : "SOURCE",
      "properties" : {
        "count" : 2
      }
    }
  }
}, {
  "class" : "uk.gov.gchq.gaffer.operation.data.EntitySeed",
  "vertex" : {
    "uk.gov.gchq.gaffer.data.element.Edge" : {
      "class" : "uk.gov.gchq.gaffer.data.element.Edge",
      "group" : "edge",
      "source" : 2,
      "destination" : 4,
      "directed" : true,
      "matchedVertex" : "SOURCE",
      "properties" : {
        "count" : 1
      }
    }
  }
}, {
  "class" : "uk.gov.gchq.gaffer.operation.data.EntitySeed",
  "vertex" : {
    "uk.gov.gchq.gaffer.data.element.Edge" : {
      "class" : "uk.gov.gchq.gaffer.data.element.Edge",
      "group" : "edge",
      "source" : 1,
      "destination" : 2,
      "directed" : true,
      "matchedVertex" : "SOURCE",
      "properties" : {
        "count" : 3
      }
    }
  }
}, {
  "class" : "uk.gov.gchq.gaffer.operation.data.EntitySeed",
  "vertex" : {
    "uk.gov.gchq.gaffer.data.element.Edge" : {
      "class" : "uk.gov.gchq.gaffer.data.element.Edge",
      "group" : "edge",
      "source" : 2,
      "destination" : 5,
      "directed" : true,
      "matchedVertex" : "SOURCE",
      "properties" : {
        "count" : 1
      }
    }
  }
} ]

ToList

Converts elements to a List. Javadoc

Note

Conversion into a List is done using an in memory ArrayList, so it is not advised for a large number of results.

Example ToList

JavaJSONPython

final OperationChain<List<? extends Element>> opChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new ToList<>())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ]
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.output.ToList"
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.ToList()
  ]
)

Results:

JavaJSON

Edge[source=1,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=2,group=entity,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=1,group=entity,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=2,destination=3,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>2]]
Edge[source=2,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Edge[source=1,destination=2,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=2,destination=5,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]

[ {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 2,
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 1,
  "properties" : {
    "count" : 3
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 3,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 2
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 2,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 3
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 5,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
} ]

ToMap

Converts elements to a Map of key-value pairs. Javadoc

Example ToMap

JavaJSONPython

final OperationChain<Iterable<? extends Map<String, Object>>> opChain = new Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new ToMap.Builder()
                .generator(new MapGenerator.Builder()
                        .group("group")
                        .vertex("vertex")
                        .source("source")
                        .property("count", "total count")
                        .build())
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ]
  }, {
    "class" : "ToMap",
    "elementGenerator" : {
      "class" : "MapGenerator",
      "fields" : {
        "GROUP" : "group",
        "VERTEX" : "vertex",
        "SOURCE" : "source",
        "count" : "total count"
      },
      "constants" : { }
    }
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.ToMap(
      element_generator=g.MapGenerator(
        fields={'GROUP': 'group', 'VERTEX': 'vertex', 'SOURCE': 'source', 'count': 'total count'},
        constants={}
      )
    )
  ]
)

Results:

JavaJSON

{group=edge, source=1, total count=1}
{group=entity, vertex=2, total count=1}
{group=entity, vertex=1, total count=3}
{group=edge, source=2, total count=2}
{group=edge, source=2, total count=1}
{group=edge, source=1, total count=3}
{group=edge, source=2, total count=1}

[ {
  "group" : "edge",
  "source" : 1,
  "total count" : 1
}, {
  "group" : "entity",
  "vertex" : 2,
  "total count" : 1
}, {
  "group" : "entity",
  "vertex" : 1,
  "total count" : 3
}, {
  "group" : "edge",
  "source" : 2,
  "total count" : 2
}, {
  "group" : "edge",
  "source" : 2,
  "total count" : 1
}, {
  "group" : "edge",
  "source" : 1,
  "total count" : 3
}, {
  "group" : "edge",
  "source" : 2,
  "total count" : 1
} ]

ToSet

Converts elements to a Set. Javadoc

Note

Conversion into a Set is done using an in memory LinkedHashSet, so it is not advised for a large number of results.

Example ToSet

JavaJSONPython

final OperationChain<Set<? extends Element>> opChain = new OperationChain.Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new ToSet<>())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ]
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.output.ToSet"
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.ToSet()
  ]
)

Results:

JavaJSON

Edge[source=1,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=2,group=entity,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=1,group=entity,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=2,destination=3,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>2]]
Edge[source=2,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Edge[source=1,destination=2,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=2,destination=5,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]

[ {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 2,
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Entity",
  "group" : "entity",
  "vertex" : 1,
  "properties" : {
    "count" : 3
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 3,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 2
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 4,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 1,
  "destination" : 2,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 3
  }
}, {
  "class" : "uk.gov.gchq.gaffer.data.element.Edge",
  "group" : "edge",
  "source" : 2,
  "destination" : 5,
  "directed" : true,
  "matchedVertex" : "SOURCE",
  "properties" : {
    "count" : 1
  }
} ]

ToSingletonList

Converts a single input of type T to a List. Javadoc

Example ToSingletonList

JavaJSONPython

final ToSingletonList<Integer> opChain = new ToSingletonList.Builder<Integer>()
        .input(4)
        .build();

{
  "class" : "ToSingletonList",
  "input" : 4
}

g.ToSingletonList(
  input=4
)

Results:

JavaJSON

4

[ 4 ]

Example of ToSingletonList in an Operation Chain

JavaJSONPython

final OperationChain<Iterable<?>> opChain = new OperationChain.Builder()
        .first(new GetAdjacentIds.Builder()
                .input(new EntitySeed(1))
                .build())
        .then(new ForEach.Builder<>()
                .operation(new OperationChain.Builder()
                        .first(new ToSingletonList<EntitySeed>())
                        .then(new GetAdjacentIds())
                        .then(new ToVertices())
                        .build())
                .build())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetAdjacentIds",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    } ]
  }, {
    "class" : "ForEach",
    "operation" : {
      "class" : "OperationChain",
      "operations" : [ {
        "class" : "ToSingletonList"
      }, {
        "class" : "GetAdjacentIds"
      }, {
        "class" : "ToVertices"
      } ]
    }
  } ]
}

g.OperationChain(
  operations=[
    g.GetAdjacentIds(
      input=[
        g.EntitySeed(
          vertex=1
        )
      ]
    ),
    g.ForEach(
      operation=g.OperationChain(
        operations=[
          g.ToSingletonList(),
          g.GetAdjacentIds(),
          g.ToVertices()
        ]
      )
    )
  ]
)

Results:

JavaJSON

[ 2 --> 3 --> 1 ]
[ 3 --> 4 --> 5 --> 1 ]

[ [ 2, 3, 1 ], [ 3, 4, 5, 1 ] ]

ToStream

Converts elements to a Stream. Javadoc

Note

Conversion into a Stream is done in memory, so it is not advised for a large number of results.

Example ToStream

JavaJSONPython

final OperationChain<Stream<? extends Element>> opChain = new Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .build())
        .then(new ToStream<>())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ]
  }, {
    "class" : "ToStream"
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.ToStream()
  ]
)

Results:

JavaJSON

Edge[source=1,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=2,group=entity,properties=Properties[count=<java.lang.Integer>1]]
Entity[vertex=1,group=entity,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=2,destination=3,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>2]]
Edge[source=2,destination=4,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]
Edge[source=1,destination=2,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>3]]
Edge[source=2,destination=5,directed=true,matchedVertex=SOURCE,group=edge,properties=Properties[count=<java.lang.Integer>1]]

{
  "parallel" : false
}

ToVertices

Converts ElementIds into vertices. Javadoc

The examples use a ToSet operation after the ToVertices operation to deduplicate the results.

Example extracting entity vertices

JavaJSONPython

final OperationChain<Set<?>> opChain = new Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .view(new View.Builder()
                        .entity("entity")
                        .build())
                .build())
        .then(new ToVertices.Builder()
                .edgeVertices(ToVertices.EdgeVertices.NONE)
                .build())
        .then(new ToSet<>())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ],
    "view" : {
      "entities" : {
        "entity" : { }
      }
    }
  }, {
    "class" : "ToVertices",
    "edgeVertices" : "NONE"
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.output.ToSet"
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      view=g.View(
        entities=[
          g.ElementDefinition(
            group="entity"
          )
        ],
        all_edges=False,
        all_entities=False
      ),
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ]
    ),
    g.ToVertices(
      edge_vertices="NONE"
    ),
    g.ToSet()
  ]
)

Results:

JavaJSON

2
1

[ 2, 1 ]

Example extracting destination vertex

JavaJSONPython

final OperationChain<Set<?>> opChain = new Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .inOutType(SeededGraphFilters.IncludeIncomingOutgoingType.OUTGOING)
                .view(new View.Builder()
                        .edge("edge")
                        .build())
                .build())
        .then(new ToVertices.Builder()
                .edgeVertices(ToVertices.EdgeVertices.DESTINATION)
                .build())
        .then(new ToSet<>())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ],
    "view" : {
      "edges" : {
        "edge" : { }
      }
    },
    "includeIncomingOutGoing" : "OUTGOING"
  }, {
    "class" : "ToVertices",
    "edgeVertices" : "DESTINATION"
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.output.ToSet"
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      view=g.View(
        edges=[
          g.ElementDefinition(
            group="edge"
          )
        ],
        all_edges=False,
        all_entities=False
      ),
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ],
      include_incoming_out_going="OUTGOING"
    ),
    g.ToVertices(
      edge_vertices="DESTINATION"
    ),
    g.ToSet()
  ]
)

Results:

JavaJSON

4
3
2
5

[ 4, 3, 2, 5 ]

Example extracting both source and destination vertices

JavaJSONPython

final OperationChain<Set<?>> opChain = new Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .inOutType(SeededGraphFilters.IncludeIncomingOutgoingType.OUTGOING)
                .view(new View.Builder()
                        .edge("edge")
                        .build())
                .build())
        .then(new ToVertices.Builder()
                .edgeVertices(ToVertices.EdgeVertices.BOTH)
                .build())
        .then(new ToSet<>())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ],
    "view" : {
      "edges" : {
        "edge" : { }
      }
    },
    "includeIncomingOutGoing" : "OUTGOING"
  }, {
    "class" : "ToVertices",
    "edgeVertices" : "BOTH"
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.output.ToSet"
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      view=g.View(
        edges=[
          g.ElementDefinition(
            group="edge"
          )
        ],
        all_edges=False,
        all_entities=False
      ),
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ],
      include_incoming_out_going="OUTGOING"
    ),
    g.ToVertices(
      edge_vertices="BOTH"
    ),
    g.ToSet()
  ]
)

Results:

JavaJSON

1
4
2
3
5

[ 1, 4, 2, 3, 5 ]

Example extracting matched vertices

JavaJSONPython

final OperationChain<Set<?>> opChain = new Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .inOutType(SeededGraphFilters.IncludeIncomingOutgoingType.OUTGOING)
                .view(new View.Builder()
                        .edge("edge")
                        .build())
                .build())
        .then(new ToVertices.Builder()
                .useMatchedVertex(ToVertices.UseMatchedVertex.EQUAL)
                .build())
        .then(new ToSet<>())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ],
    "view" : {
      "edges" : {
        "edge" : { }
      }
    },
    "includeIncomingOutGoing" : "OUTGOING"
  }, {
    "class" : "ToVertices",
    "useMatchedVertex" : "EQUAL"
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.output.ToSet"
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      view=g.View(
        edges=[
          g.ElementDefinition(
            group="edge"
          )
        ],
        all_edges=False,
        all_entities=False
      ),
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ],
      include_incoming_out_going="OUTGOING"
    ),
    g.ToVertices(
      use_matched_vertex="EQUAL"
    ),
    g.ToSet()
  ]
)

Results:

JavaJSON

1
2

[ 1, 2 ]

Example extracting opposite matched vertices

JavaJSONPython

final OperationChain<Set<?>> opChain = new Builder()
        .first(new GetElements.Builder()
                .input(new EntitySeed(1), new EntitySeed(2))
                .inOutType(SeededGraphFilters.IncludeIncomingOutgoingType.OUTGOING)
                .view(new View.Builder()
                        .edge("edge")
                        .build())
                .build())
        .then(new ToVertices.Builder()
                .useMatchedVertex(ToVertices.UseMatchedVertex.OPPOSITE)
                .build())
        .then(new ToSet<>())
        .build();

{
  "class" : "OperationChain",
  "operations" : [ {
    "class" : "GetElements",
    "input" : [ {
      "class" : "EntitySeed",
      "vertex" : 1
    }, {
      "class" : "EntitySeed",
      "vertex" : 2
    } ],
    "view" : {
      "edges" : {
        "edge" : { }
      }
    },
    "includeIncomingOutGoing" : "OUTGOING"
  }, {
    "class" : "ToVertices",
    "useMatchedVertex" : "OPPOSITE"
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.output.ToSet"
  } ]
}

g.OperationChain(
  operations=[
    g.GetElements(
      view=g.View(
        edges=[
          g.ElementDefinition(
            group="edge"
          )
        ],
        all_edges=False,
        all_entities=False
      ),
      input=[
        g.EntitySeed(
          vertex=1
        ),
        g.EntitySeed(
          vertex=2
        )
      ],
      include_incoming_out_going="OUTGOING"
    ),
    g.ToVertices(
      use_matched_vertex="OPPOSITE"
    ),
    g.ToSet()
  ]
)

Results:

JavaJSON

4
3
2
5

[ 4, 3, 2, 5 ]

GetGraphCreatedTime

Gets the creation date of the current graph. Javadoc

Example getting the graph created time

JavaJSONPython

final GetGraphCreatedTime operation = new GetGraphCreatedTime();

{
        "class": "uk.gov.gchq.gaffer.operation.impl.get.GetGraphCreatedTime"
}

g.GetGraphCreatedTime()

Results:

JavaJSON

{graphId=2024-08-22T12:37:53.498}

{
  "graphId": "2024-08-22T12:37:53.498"
}

GetSchema

Gets the Schema of a Graph. Javadoc

Example getting full schema

This operation defaults the compact field to false, thereby returning the full Schema.

JavaJSONPython

final GetSchema operation = new GetSchema();

{
  "class" : "GetSchema",
  "compact" : false
}

g.GetSchema(
  compact=False
)

Results:

JavaJSON

{
  "edges" : {
    "edge" : {
      "description" : "test edge",
      "source" : "int",
      "destination" : "int",
      "directed" : "true",
      "properties" : {
        "count" : "count"
      }
    },
    "edge1" : {
      "source" : "int",
      "destination" : "int",
      "directed" : "true",
      "properties" : {
        "count" : "count"
      }
    }
  },
  "entities" : {
    "entity1" : {
      "vertex" : "int",
      "properties" : {
        "count" : "count"
      }
    },
    "entity" : {
      "description" : "test entity",
      "vertex" : "int",
      "properties" : {
        "count" : "count"
      }
    },
    "cardinality" : {
      "description" : "An entity that is added to every vertex representing the connectivity of the vertex.",
      "vertex" : "int",
      "properties" : {
        "edgeGroup" : "set",
        "hllp" : "hllp",
        "count" : "count"
      },
      "groupBy" : [ "edgeGroup" ]
    }
  },
  "types" : {
    "int" : {
      "class" : "Integer",
      "aggregateFunction" : {
        "class" : "Sum"
      }
    },
    "true" : {
      "class" : "Boolean",
      "validateFunctions" : [ {
        "class" : "IsTrue"
      } ]
    },
    "count" : {
      "class" : "Integer",
      "aggregateFunction" : {
        "class" : "Sum"
      }
    },
    "set" : {
      "class" : "TreeSet",
      "aggregateFunction" : {
        "class" : "CollectionConcat"
      }
    },
    "hllp" : {
      "class" : "com.clearspring.analytics.stream.cardinality.HyperLogLogPlus",
      "aggregateFunction" : {
        "class" : "HyperLogLogPlusAggregator"
      },
      "serialiser" : {
        "class" : "HyperLogLogPlusSerialiser"
      }
    }
  }
}

{
  "edges" : {
    "edge" : {
      "description" : "test edge",
      "source" : "int",
      "destination" : "int",
      "directed" : "true",
      "properties" : {
        "count" : "count"
      }
    },
    "edge1" : {
      "source" : "int",
      "destination" : "int",
      "directed" : "true",
      "properties" : {
        "count" : "count"
      }
    }
  },
  "entities" : {
    "entity1" : {
      "vertex" : "int",
      "properties" : {
        "count" : "count"
      }
    },
    "entity" : {
      "description" : "test entity",
      "vertex" : "int",
      "properties" : {
        "count" : "count"
      }
    },
    "cardinality" : {
      "description" : "An entity that is added to every vertex representing the connectivity of the vertex.",
      "vertex" : "int",
      "properties" : {
        "edgeGroup" : "set",
        "hllp" : "hllp",
        "count" : "count"
      },
      "groupBy" : [ "edgeGroup" ]
    }
  },
  "types" : {
    "int" : {
      "class" : "java.lang.Integer",
      "aggregateFunction" : {
        "class" : "uk.gov.gchq.koryphe.impl.binaryoperator.Sum"
      }
    },
    "true" : {
      "class" : "java.lang.Boolean",
      "validateFunctions" : [ {
        "class" : "uk.gov.gchq.koryphe.impl.predicate.IsTrue"
      } ]
    },
    "count" : {
      "class" : "java.lang.Integer",
      "aggregateFunction" : {
        "class" : "uk.gov.gchq.koryphe.impl.binaryoperator.Sum"
      }
    },
    "set" : {
      "class" : "java.util.TreeSet",
      "aggregateFunction" : {
        "class" : "uk.gov.gchq.koryphe.impl.binaryoperator.CollectionConcat"
      }
    },
    "hllp" : {
      "class" : "com.clearspring.analytics.stream.cardinality.HyperLogLogPlus",
      "aggregateFunction" : {
        "class" : "uk.gov.gchq.gaffer.sketches.clearspring.cardinality.binaryoperator.HyperLogLogPlusAggregator"
      },
      "serialiser" : {
        "class" : "uk.gov.gchq.gaffer.sketches.clearspring.cardinality.serialisation.HyperLogLogPlusSerialiser"
      }
    }
  }
}

Example getting compact schema

This operation will retrieve the compact Schema from the store, rather than the full schema.

JavaJSONPython

final GetSchema operation = new GetSchema.Builder()
        .compact(true)
        .build();

{
  "class" : "GetSchema",
  "compact" : true
}

g.GetSchema(
  compact=True
)

Results:

JavaJSON

{
  "edges" : {
    "edge" : {
      "source" : "int",
      "destination" : "int",
      "directed" : "true",
      "properties" : {
        "count" : "count"
      }
    },
    "edge1" : {
      "source" : "int",
      "destination" : "int",
      "directed" : "true",
      "properties" : {
        "count" : "count"
      }
    }
  },
  "entities" : {
    "entity1" : {
      "vertex" : "int",
      "properties" : {
        "count" : "count"
      }
    },
    "entity" : {
      "vertex" : "int",
      "properties" : {
        "count" : "count"
      }
    },
    "cardinality" : {
      "vertex" : "int",
      "properties" : {
        "edgeGroup" : "set",
        "hllp" : "hllp",
        "count" : "count"
      },
      "groupBy" : [ "edgeGroup" ]
    }
  },
  "types" : {
    "int" : {
      "class" : "Integer",
      "aggregateFunction" : {
        "class" : "Sum"
      }
    },
    "true" : {
      "class" : "Boolean",
      "validateFunctions" : [ {
        "class" : "IsTrue"
      } ]
    },
    "count" : {
      "class" : "Integer",
      "aggregateFunction" : {
        "class" : "Sum"
      },
      "serialiser" : {
        "class" : "OrderedIntegerSerialiser"
      }
    },
    "set" : {
      "class" : "TreeSet",
      "aggregateFunction" : {
        "class" : "CollectionConcat"
      },
      "serialiser" : {
        "class" : "TreeSetStringSerialiser"
      }
    },
    "hllp" : {
      "class" : "com.clearspring.analytics.stream.cardinality.HyperLogLogPlus",
      "aggregateFunction" : {
        "class" : "HyperLogLogPlusAggregator"
      },
      "serialiser" : {
        "class" : "HyperLogLogPlusSerialiser"
      }
    }
  },
  "vertexSerialiser" : {
    "class" : "OrderedIntegerSerialiser"
  }
}

{
  "edges" : {
    "edge" : {
      "source" : "int",
      "destination" : "int",
      "directed" : "true",
      "properties" : {
        "count" : "count"
      }
    },
    "edge1" : {
      "source" : "int",
      "destination" : "int",
      "directed" : "true",
      "properties" : {
        "count" : "count"
      }
    }
  },
  "entities" : {
    "entity1" : {
      "vertex" : "int",
      "properties" : {
        "count" : "count"
      }
    },
    "entity" : {
      "vertex" : "int",
      "properties" : {
        "count" : "count"
      }
    },
    "cardinality" : {
      "vertex" : "int",
      "properties" : {
        "edgeGroup" : "set",
        "hllp" : "hllp",
        "count" : "count"
      },
      "groupBy" : [ "edgeGroup" ]
    }
  },
  "types" : {
    "int" : {
      "class" : "java.lang.Integer",
      "aggregateFunction" : {
        "class" : "uk.gov.gchq.koryphe.impl.binaryoperator.Sum"
      }
    },
    "true" : {
      "class" : "java.lang.Boolean",
      "validateFunctions" : [ {
        "class" : "uk.gov.gchq.koryphe.impl.predicate.IsTrue"
      } ]
    },
    "count" : {
      "class" : "java.lang.Integer",
      "aggregateFunction" : {
        "class" : "uk.gov.gchq.koryphe.impl.binaryoperator.Sum"
      },
      "serialiser" : {
        "class" : "uk.gov.gchq.gaffer.serialisation.implementation.ordered.OrderedIntegerSerialiser"
      }
    },
    "set" : {
      "class" : "java.util.TreeSet",
      "aggregateFunction" : {
        "class" : "uk.gov.gchq.koryphe.impl.binaryoperator.CollectionConcat"
      },
      "serialiser" : {
        "class" : "uk.gov.gchq.gaffer.serialisation.implementation.TreeSetStringSerialiser"
      }
    },
    "hllp" : {
      "class" : "com.clearspring.analytics.stream.cardinality.HyperLogLogPlus",
      "aggregateFunction" : {
        "class" : "uk.gov.gchq.gaffer.sketches.clearspring.cardinality.binaryoperator.HyperLogLogPlusAggregator"
      },
      "serialiser" : {
        "class" : "uk.gov.gchq.gaffer.sketches.clearspring.cardinality.serialisation.HyperLogLogPlusSerialiser"
      }
    }
  },
  "vertexSerialiser" : {
    "class" : "uk.gov.gchq.gaffer.serialisation.implementation.ordered.OrderedIntegerSerialiser"
  }
}

Variables

Operations associated with storing variables in the operation context map. Note that the context only exists during that operation and so these operations must be contained within the same operation chain to work.

SetVariable

Stores a variable in the Context variable map. Takes a variable name and an input and stores them as a key value pair. Javadoc

Example setting a variable

JavaJSON

final SetVariable op = new SetVariable.Builder()
        .variableName("varName")
        .input(5)
        .build();

{
    "class" : "SetVariable",
    "variableName": "varName",
    "input": 5
}

GetVariable

Gets a variable from the Context variable map. Takes the variable name as an input. Javadoc

Example getting a variable

JavaJSON

final GetVariable op = new GetVariable.Builder()
        .variableName("varName")
        .build();

{
    "class" : "GetVariable",
    "variableName": "varName"
}

Results:

JavaJSON

5

5

GetVariables

Gets all the variables from the Context variable map. Takes a list of variable names as an input. Javadoc

Example getting all variables

JavaJSON

final List<String> variableNames = Arrays.asList("varName");
final GetVariables op = new GetVariables.Builder()
        .variableNames(variableNames)
        .build();

{
    "class" : "GetVariables",
    "variableNames": ["varName"]
}

Results:

JavaJSON

5

5

GetTraits

Gets the traits of the current store. Javadoc

Example getting all traits

currentTraits is an optional field that holds a boolean value. When false the operation returns a list of all supported traits from the store, but if true then a list of current traits is returned. Defaults to true.

JavaJSONPython

final GetTraits operation = new GetTraits.Builder()
        .currentTraits(false)
        .build();

{
  "class" : "GetTraits",
  "currentTraits" : false
}

g.GetTraits(
  current_traits=False
)

Results:

JavaJSON

QUERY_AGGREGATION
VISIBILITY
MATCHED_VERTEX
TRANSFORMATION
INGEST_AGGREGATION
PRE_AGGREGATION_FILTERING
POST_TRANSFORMATION_FILTERING
POST_AGGREGATION_FILTERING

[ "QUERY_AGGREGATION", "VISIBILITY", "MATCHED_VERTEX", "TRANSFORMATION", "INGEST_AGGREGATION", "PRE_AGGREGATION_FILTERING", "POST_TRANSFORMATION_FILTERING", "POST_AGGREGATION_FILTERING" ]

Example getting current traits

This will only return traits that are applicable to your current schema. This schema doesn't have a visibility property, so the VISIBILITY trait is not returned.

JavaJSONPython

final GetTraits operation = new GetTraits.Builder()
        .currentTraits(true)
        .build();

{
  "class" : "GetTraits",
  "currentTraits" : true
}

g.GetTraits(
  current_traits=True
)

Results:

JavaJSON

QUERY_AGGREGATION
MATCHED_VERTEX
TRANSFORMATION
INGEST_AGGREGATION
PRE_AGGREGATION_FILTERING
POST_TRANSFORMATION_FILTERING
POST_AGGREGATION_FILTERING

[ "QUERY_AGGREGATION", "MATCHED_VERTEX", "TRANSFORMATION", "INGEST_AGGREGATION", "PRE_AGGREGATION_FILTERING", "POST_TRANSFORMATION_FILTERING", "POST_AGGREGATION_FILTERING" ]

HasTrait

Checks if a Store has a given trait. Javadoc

Example checking if store has trait

currentTraits is an optional field that holds a boolean value and defaults to true. It is used to check if the provided traits exists in the either the store default (false) or the schema current traits (true).

JavaJSON

final HasTrait operation = new HasTrait.Builder()
        .currentTraits(false)
        .trait(PRE_AGGREGATION_FILTERING)
        .build();

{
    "class" : "HasTrait",
    "currentTraits" : false,
    "trait": "PRE_AGGREGATION_FILTERING"
}

Results:

JavaJSON

true

true

DeleteAllData

Deletes all retained data including deleting the graph. Javadoc

Note this operation does not return any response.

operationsDeclarations.json

{
    "operations": [
        {
            "operation": "uk.gov.gchq.gaffer.store.operation.DeleteAllData",
            "handler": {
                "class": "uk.gov.gchq.gaffer.accumulostore.operation.handler.DeleteAllDataHandler"
            }
        }
    ]
}

Example deleting all data

JavaJSONPython

final DeleteAllData operation = new DeleteAllData()

{
  "class" : "DeleteAllData"
}

g.DeleteAllData()