org.apache.giraph.utils

Class VertexIterator<I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable>

java.lang.Object

org.apache.giraph.utils.VertexIterator<I,V,E>

Type Parameters:

I - Vertex id

V - Vertex value

E - Edge value

public class VertexIterator<I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable>
extends Object

Iterates over vertices stored in an ExtendedDataOutput such that the ownership of the vertex id can be transferred to another object. This optimization cuts down on the number of objects instantiated and garbage collected

Constructor Summary

Constructors

Constructor and Description
VertexIterator(ExtendedDataOutput extendedDataOutput, ImmutableClassesGiraphConfiguration<I,V,E> configuration) Constructor.

Method Summary

Modifier and Type	Method and Description
I	getCurrentVertexId() Get the current vertex id.
Vertex<I,V,E>	getVertex()
boolean	hasNext() Returns true if the iteration has more elements.
void	next() Moves to the next element in the iteration.
I	releaseCurrentVertexId() The backing store of the current vertex id is now released.
Vertex<I,V,E>	releaseVertex() Release the ownership of the Vertex object to the caller

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

VertexIterator

public VertexIterator(ExtendedDataOutput extendedDataOutput,
                      ImmutableClassesGiraphConfiguration<I,V,E> configuration)

Constructor.

Parameters:

extendedDataOutput - Extended data output

configuration - Configuration

Method Detail

hasNext

public boolean hasNext()

Returns true if the iteration has more elements.

Returns:

True if the iteration has more elements.

next

public void next()

Moves to the next element in the iteration.

getCurrentVertexId

public I getCurrentVertexId()

Get the current vertex id. Ihis object's contents are only guaranteed until next() is called. To take ownership of this object call releaseCurrentVertexId() after getting a reference to this object.

Returns:

Current vertex id

releaseCurrentVertexId

public I releaseCurrentVertexId()

The backing store of the current vertex id is now released. Further calls to getCurrentVertexId () without calling next() will return null.

Returns:

Current vertex id that was released

getVertex

public Vertex<I,V,E> getVertex()

releaseVertex

public Vertex<I,V,E> releaseVertex()

Release the ownership of the Vertex object to the caller

Returns:

Released Vertex object