Package com.google.common.graph

Class EndpointPair<N>

java.lang.Object

com.google.common.graph.EndpointPair<N>

All Implemented Interfaces:

Iterable<N>

@Beta
@Immutable(containerOf="N")
public abstract class EndpointPair<N>
extends Object
implements Iterable<N>

An immutable pair representing the two endpoints of an edge in a graph. The EndpointPair of a directed edge is an ordered pair of nodes (source() and target()). The EndpointPair of an undirected edge is an unordered pair of nodes (nodeU() and nodeV()).

The edge is a self-loop if, and only if, the two endpoints are equal.

Since:

20.0

Author:

James Sexton

Method Summary

Modifier and Type	Method	Description
N	adjacentNode(N node)	Returns the node that is adjacent to node along the origin edge.
abstract boolean	equals(Object obj)	Two ordered EndpointPairs are equal if their source() and target() are equal.
abstract int	hashCode()	The hashcode of an ordered EndpointPair is equal to Objects.hashCode(source(), target()).
abstract boolean	isOrdered()	Returns true if this EndpointPair is an ordered pair (i.e.
UnmodifiableIterator<N>	iterator()	Iterates in the order nodeU(), nodeV().
N	nodeU()	If this EndpointPair isOrdered() returns the source(); otherwise, returns an arbitrary (but consistent) endpoint of the origin edge.
N	nodeV()	Returns the node adjacent to nodeU() along the origin edge.
static <N> EndpointPair<N>	ordered(N source, N target)	Returns an EndpointPair representing the endpoints of a directed edge.
abstract N	source()	If this EndpointPair isOrdered(), returns the node which is the source.
abstract N	target()	If this EndpointPair isOrdered(), returns the node which is the target.
static <N> EndpointPair<N>	unordered(N nodeU, N nodeV)	Returns an EndpointPair representing the endpoints of an undirected edge.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Method Detail

ordered

public static <N> EndpointPair<N> ordered(N source,
                                          N target)

Returns an EndpointPair representing the endpoints of a directed edge.

unordered

public static <N> EndpointPair<N> unordered(N nodeU,
                                            N nodeV)

Returns an EndpointPair representing the endpoints of an undirected edge.

source

public abstract N source()

If this EndpointPair isOrdered(), returns the node which is the source.

Throws:

UnsupportedOperationException - if this EndpointPair is not ordered

target

public abstract N target()

If this EndpointPair isOrdered(), returns the node which is the target.

Throws:

UnsupportedOperationException - if this EndpointPair is not ordered

nodeU

public final N nodeU()

If this EndpointPair isOrdered() returns the source(); otherwise, returns an arbitrary (but consistent) endpoint of the origin edge.

nodeV

public final N nodeV()

Returns the node adjacent to nodeU() along the origin edge. If this EndpointPair isOrdered(), this is equal to target().

adjacentNode

public final N adjacentNode(N node)

Returns the node that is adjacent to node along the origin edge.

Throws:

IllegalArgumentException - if this EndpointPair does not contain node

Since:

20.0 (but the argument type was changed from Object to N in 31.0)

isOrdered

public abstract boolean isOrdered()

Returns true if this EndpointPair is an ordered pair (i.e. represents the endpoints of a directed edge).

iterator

public final UnmodifiableIterator<N> iterator()

Iterates in the order nodeU(), nodeV().

Specified by:

iterator in interface Iterable<N>

Returns:

an Iterator.

equals

public abstract boolean equals(@CheckForNull
                               Object obj)

Two ordered EndpointPairs are equal if their source() and target() are equal. Two unordered EndpointPairs are equal if they contain the same nodes. An ordered EndpointPair is never equal to an unordered EndpointPair.

Overrides:

equals in class Object

Parameters:

obj - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

See Also:

Object.hashCode(), HashMap

hashCode

public abstract int hashCode()

The hashcode of an ordered EndpointPair is equal to Objects.hashCode(source(), target()). The hashcode of an unordered EndpointPair is equal to nodeU().hashCode() + nodeV().hashCode().

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)