Map
See javadoc - uk.gov.gchq.gaffer.operation.impl.Map
Available since Gaffer version 1.2.0
Maps an input to an output using provided functions
Required fields
The following fields are required:
- functions
Examples
Extract from get elements
This simple example demonstrates retrieving elements from the "entity" group, from which the first item is extracted.
Using this directed graph:
--> 4 <--
/ ^ \
/ | \
1 --> 2 --> 3
\
--> 5
Java
JSON
Full JSON
Python
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"
} ]
} ]
}{
"class" : "uk.gov.gchq.gaffer.operation.OperationChain",
"operations" : [ {
"class" : "uk.gov.gchq.gaffer.operation.impl.get.GetElements",
"input" : [ {
"class" : "uk.gov.gchq.gaffer.operation.data.EntitySeed",
"vertex" : 1
}, {
"class" : "uk.gov.gchq.gaffer.operation.data.EntitySeed",
"vertex" : 2
} ],
"view" : {
"entities" : {
"entity" : { }
}
}
}, {
"class" : "uk.gov.gchq.gaffer.operation.impl.Map",
"functions" : [ {
"class" : "uk.gov.gchq.koryphe.impl.function.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()
]
)
]
)Result:
Java
JSON
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
}
}Extract 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.
Using this directed graph:
--> 4 <--
/ ^ \
/ | \
1 --> 2 --> 3
\
--> 5
Java
JSON
Full JSON
Python
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"
} ]
}{
"class" : "uk.gov.gchq.gaffer.operation.OperationChain",
"operations" : [ {
"class" : "uk.gov.gchq.gaffer.operation.impl.GetWalks",
"input" : [ {
"class" : "uk.gov.gchq.gaffer.operation.data.EntitySeed",
"vertex" : 1
}, {
"class" : "uk.gov.gchq.gaffer.operation.data.EntitySeed",
"vertex" : 2
} ],
"operations" : [ {
"class" : "uk.gov.gchq.gaffer.operation.OperationChain",
"operations" : [ {
"class" : "uk.gov.gchq.gaffer.operation.impl.get.GetElements",
"view" : {
"edges" : {
"edge" : { }
}
}
} ]
} ],
"resultsLimit" : 100
}, {
"class" : "uk.gov.gchq.gaffer.operation.impl.Map",
"functions" : [ {
"class" : "uk.gov.gchq.koryphe.impl.function.IterableFunction",
"functions" : [ {
"class" : "uk.gov.gchq.gaffer.data.graph.function.walk.ExtractWalkEdgesFromHop",
"hop" : 0
}, {
"class" : "uk.gov.gchq.koryphe.impl.function.FirstItem"
} ]
} ]
}, {
"class" : "uk.gov.gchq.gaffer.operation.impl.output.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()
]
)Result:
Java
JSON
1
2[ 1, 2 ]