com.codemelon.graph.graph

Class AbstractGraph<T extends Vertex>

java.lang.Object

com.codemelon.graph.graph.AbstractGraph<T>

Direct Known Subclasses:

BfsGraph, DirectedEdgeDataGraph, DirectedSimpleGraph, UndirectedEdgeDataGraph, UndirectedSimpleGraph

public abstract class AbstractGraph<T extends Vertex>
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
AbstractGraph() Initialize graph to a default initial capacity of 16 vertices
AbstractGraph(java.util.Collection<T> vertices) Use the vertices in a collection as the initial vertices in the graph
AbstractGraph(int initialCapacity) Initialize graph to have capacity for the given number of vertices

Method Summary

Methods

Modifier and Type	Method and Description
boolean	addVertex(T vertex) Inserts vertex if it is not already present.
boolean	containsEdge(T from, T to) Shows whether or not the graph contains the specified edge
boolean	containsVertex(Vertex vertex) Shows whether or not the graph contains the given vertex
abstract int	edgeCount() Returns the number of edges in the graph.
java.util.Set<T>	getVertices() Returns a set containing the vertices in the graph.
boolean	removeVertex(Vertex vertex) Remove a vertex from the graph.
int	vertexCount() Number of vertices in the graph
java.util.Iterator<T>	vertexIterator() Returns an iterator over the vertices in the graph

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractGraph

public AbstractGraph()

Initialize graph to a default initial capacity of 16 vertices

AbstractGraph

public AbstractGraph(int initialCapacity)

Initialize graph to have capacity for the given number of vertices

Parameters:

initialCapacity - expected number of vertices

AbstractGraph

public AbstractGraph(java.util.Collection<T> vertices)

Use the vertices in a collection as the initial vertices in the graph

Parameters:

vertices - collection of vertices that will make up the initial vertices of the graph

Method Detail

addVertex

public final boolean addVertex(T vertex)

Inserts vertex if it is not already present.

Parameters:

vertex - vertex to be inserted

Returns:

true if the graph did not already contained the specified vertex

containsVertex

public final boolean containsVertex(Vertex vertex)

Shows whether or not the graph contains the given vertex

Parameters:

vertex - the vertex whose presence in the graph is to be tested

Returns:

true if the vertex is present in the graph

removeVertex

public final boolean removeVertex(Vertex vertex)

Remove a vertex from the graph. The vertex is removed along with its adjacency list, and it is also removed from the adjacency set of the other vertices in the graph. After this method call, not only will the vertex not belong to the graph, but the adjacency list of the vertex will also be cleared.

Parameters:

vertex - vertex to be removed from the graph

Returns:

true iff the vertex was found in the graph

vertexCount

public final int vertexCount()

Number of vertices in the graph

Returns:

number of vertices in the graph

getVertices

public final java.util.Set<T> getVertices()

Returns a set containing the vertices in the graph.

Returns:

the set of vertices in the graph

vertexIterator

public final java.util.Iterator<T> vertexIterator()

Returns an iterator over the vertices in the graph

Returns:

iterator over the graph's vertices

containsEdge

public final boolean containsEdge(T from,
                   T to)

Shows whether or not the graph contains the specified edge

Parameters:

from - the tail or source vertex of the edge for which we are testing

to - the head or target vertex of the edge for which we are testing

Returns:

true if the edge from the given tail to the given head exists in the graph.

Throws:

java.lang.IllegalArgumentException - if either vertex is not present in the graph

edgeCount

public abstract int edgeCount()

Returns the number of edges in the graph. This method is abstract because the implementation will differ in directed and undirected graphs.

Returns:

the number of edges in the graph