org.apache.giraph.utils

Class EdgeIterables

java.lang.Object

org.apache.giraph.utils.EdgeIterables

public class EdgeIterables
extends Object

Utility methods for iterables of edges.

Method Summary

Modifier and Type	Method and Description
static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.WritableComparable> ArrayList<Edge<I,E>>	copy(Iterable<Edge<I,E>> edges) Make a deep copy of an edge iterable and return it as an ArrayList.
static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.WritableComparable> boolean	equals(Iterable<Edge<I,E>> e1, Iterable<Edge<I,E>> e2) Compare two edge iterables element-wise.
static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.Writable> void	initialize(OutEdges<I,E> edges, Iterable<Edge<I,E>> edgesIterable) Initialize edges data structure and add the edges from edgesIterable.
static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.WritableComparable> boolean	sameEdges(Iterable<Edge<I,E>> e1, Iterable<Edge<I,E>> e2) Compare two edge iterables up to reordering.
static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.Writable> int	size(Iterable<Edge<I,E>> edges) Get the size of edges.

Methods inherited from class java.lang.Object

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

Method Detail

equals

public static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.WritableComparable> boolean equals(Iterable<Edge<I,E>> e1,
                                                                                                                                   Iterable<Edge<I,E>> e2)

Compare two edge iterables element-wise. The edge value type needs to be Comparable.

Type Parameters:

I - Vertex id

E - Edge value

Parameters:

e1 - First edge iterable

e2 - Second edge iterable

Returns:

Whether the two iterables are equal element-wise

copy

public static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.WritableComparable> ArrayList<Edge<I,E>> copy(Iterable<Edge<I,E>> edges)

Make a deep copy of an edge iterable and return it as an ArrayList. Note: this method is slow since it has to deserialize all serialize all the ids and values. It should only be used in unit tests.

Type Parameters:

I - Vertex id

E - Edge value

Parameters:

edges - Iterable of edges

Returns:

A new list with copies of all the edges

sameEdges

public static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.WritableComparable> boolean sameEdges(Iterable<Edge<I,E>> e1,
                                                                                                                                      Iterable<Edge<I,E>> e2)

Compare two edge iterables up to reordering. The edge value type needs to be Comparable.

Type Parameters:

I - Vertex id

E - Edge value

Parameters:

e1 - First edge iterable

e2 - Second edge iterable

Returns:

Whether the two iterables are equal up to reordering

size

public static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.Writable> int size(Iterable<Edge<I,E>> edges)

Get the size of edges. Optimized implementation for cases when edges is instance of OutEdges or Collection which only calls size() method from these classes.

Type Parameters:

I - Vertex index

E - Edge value

Parameters:

edges - Edges

Returns:

Size of edges

initialize

public static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.Writable> void initialize(OutEdges<I,E> edges,
                                                                                                                          Iterable<Edge<I,E>> edgesIterable)

Initialize edges data structure and add the edges from edgesIterable. If edgesIterable is instance of OutEdges or Collection edges will be initialized with size of edgesIterable, otherwise edges will be initialized without size.

Type Parameters:

I - Vertex index

E - Edge value

Parameters:

edges - Edges to initialize

edgesIterable - Iterable whose edges to use