com.opensymphony.xwork2.config.providers

Class DirectedGraph<T>

java.lang.Object

com.opensymphony.xwork2.config.providers.DirectedGraph<T>

All Implemented Interfaces:

Iterable<T>

public final class DirectedGraph<T>
extends Object
implements Iterable<T>

Constructor Summary

Constructors

Constructor and Description
DirectedGraph()

Method Summary

Methods

Modifier and Type	Method and Description
void	addEdge(T start, T dest) Given a start node, and a destination, adds an arc from the start node to the destination.
boolean	addNode(T node) Adds a new node to the graph.
boolean	edgeExists(T start, T end) Given two nodes in the graph, returns whether there is an edge from the first node to the second node.
Set<T>	edgesFrom(T node) Given a node in the graph, returns an immutable view of the edges leaving that node as a set of endpoints.
boolean	isEmpty() Returns whether the graph is empty.
Iterator<T>	iterator() Returns an iterator that can traverse the nodes in the graph.
void	removeEdge(T start, T dest) Removes the edge from start to dest from the graph.
int	size() Returns the number of nodes in the graph.

Methods inherited from class java.lang.Object

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

Constructor Detail

DirectedGraph

public DirectedGraph()

Method Detail

addNode

public boolean addNode(T node)

Adds a new node to the graph. If the node already exists, this function is a no-op.

Parameters:

node - The node to add.

Returns:

Whether or not the node was added.

addEdge

public void addEdge(T start,
           T dest)

Given a start node, and a destination, adds an arc from the start node to the destination. If an arc already exists, this operation is a no-op. If either endpoint does not exist in the graph, throws a NoSuchElementException.

Parameters:

start - The start node.

dest - The destination node.

Throws:

NoSuchElementException - If either the start or destination nodes do not exist.

removeEdge

public void removeEdge(T start,
              T dest)

Removes the edge from start to dest from the graph. If the edge does not exist, this operation is a no-op. If either endpoint does not exist, this throws a NoSuchElementException.

Parameters:

start - The start node.

dest - The destination node.

Throws:

NoSuchElementException - If either node is not in the graph.

edgeExists

public boolean edgeExists(T start,
                 T end)

Given two nodes in the graph, returns whether there is an edge from the first node to the second node. If either node does not exist in the graph, throws a NoSuchElementException.

Parameters:

start - The start node.

end - The destination node.

Returns:

Whether there is an edge from start to end.

Throws:

NoSuchElementException - If either endpoint does not exist.

edgesFrom

public Set<T> edgesFrom(T node)

Given a node in the graph, returns an immutable view of the edges leaving that node as a set of endpoints.

Parameters:

node - The node whose edges should be queried.

Returns:

An immutable view of the edges leaving that node.

Throws:

NoSuchElementException - If the node does not exist.

iterator

public Iterator<T> iterator()

Returns an iterator that can traverse the nodes in the graph.

Specified by:

iterator in interface Iterable<T>

Returns:

An iterator that traverses the nodes in the graph.

size

public int size()

Returns the number of nodes in the graph.

Returns:

The number of nodes in the graph.

isEmpty

public boolean isEmpty()

Returns whether the graph is empty.

Returns:

Whether the graph is empty.