simudyne.core.graph

Interface VertexAggregator<T extends Vertex,S extends VertexAggregator<T,S>>

Type Parameters:

T - The type of the vertex to be observed.

S - The type of the class implementing VertexAggregator

All Superinterfaces:

java.io.Serializable

public interface VertexAggregator<T extends Vertex,S extends VertexAggregator<T,S>>
extends java.io.Serializable

The VertexAggregator interface allows the definition of a custom aggregator that can be used to collect vertex data for reporting. VertexAggregators are used as a parameter for the VertexSelection.aggregate(SerializableSupplier) parameter for VertexSelection selections.

An VertexAggregator is given zero or more observations of vertices, which it can use to update an internal state. These states are then merged together to form the final state of the aggregator. Although aggregators are created and merged in parallel, the actual implementation of an VertexAggregator does not need to be threadsafe.

The second type parameter argument should be the type of the implementing class, for example:

 class MyAggregator implements VertexAggregator<MyVertex, MyAggregator> {
   // ...
 }
 

Method Summary

Modifier and Type	Method and Description
void	merge(S other) Given another aggregator of the same type, modify this aggregator's internal state to be the combination of the two.
void	observe(T vertex) Take an observation of a single vertex of type T.

Method Detail

observe

void observe(T vertex)

Take an observation of a single vertex of type T. The aggregator should modify its state in response to the observation.

For example, a summing aggregator would add 1 to an internal count field.

Parameters:

vertex - An vertex instance.

merge

void merge(S other)

Given another aggregator of the same type, modify this aggregator's internal state to be the combination of the two.

For example, a summing aggregator would add the count contained in to this instance.

Parameters:

other - Another aggregator instance of the same type, to merge into this instance.