Limit

See javadoc - uk.gov.gchq.gaffer.operation.impl.Limit

Available since Gaffer version 1.0.0

Limits the number of items

Required fields

The following fields are required:

  • resultLimit

Examples

Limit elements to 3

Using this directed graph:


    --> 4 <--
  /     ^     \
 /      |      \
1  -->  2  -->  3
         \
           -->  5

Java
JSON
Full JSON
Python
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
  } ]
}
{
  "class" : "uk.gov.gchq.gaffer.operation.OperationChain",
  "operations" : [ {
    "class" : "uk.gov.gchq.gaffer.operation.impl.get.GetAllElements"
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.Limit",
    "resultLimit" : 3,
    "truncate" : true
  } ]
}
g.OperationChain( 
  operations=[ 
    g.GetAllElements(), 
    g.Limit( 
      result_limit=3, 
      truncate=True 
    ) 
  ] 
)

Result:

Java
JSON
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
  }
} ]

Limit 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.

Java
JSON
Full JSON
Python
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
  } ]
}
{
  "class" : "uk.gov.gchq.gaffer.operation.OperationChain",
  "operations" : [ {
    "class" : "uk.gov.gchq.gaffer.operation.impl.get.GetAllElements"
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.Limit",
    "resultLimit" : 3,
    "truncate" : false
  } ]
}
g.OperationChain( 
  operations=[ 
    g.GetAllElements(), 
    g.Limit( 
      result_limit=3, 
      truncate=False 
    ) 
  ] 
)

Limit 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.

Using this directed graph:


    --> 4 <--
  /     ^     \
 /      |      \
1  -->  2  -->  3
         \
           -->  5

Java
JSON
Full JSON
Python
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
  } ]
}
{
  "class" : "uk.gov.gchq.gaffer.operation.OperationChain",
  "operations" : [ {
    "class" : "uk.gov.gchq.gaffer.operation.impl.get.GetAllElements"
  }, {
    "class" : "uk.gov.gchq.gaffer.operation.impl.Limit",
    "resultLimit" : 3,
    "truncate" : true
  } ]
}
g.OperationChain( 
  operations=[ 
    g.GetAllElements(), 
    g.Limit( 
      result_limit=3, 
      truncate=True 
    ) 
  ] 
)

Result:

Java
JSON
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
  }
} ]

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