Class Edge<V,E>

java.lang.Object

Edge<V,E>

public class Edge<V,E>
extends java.lang.Object

An Edge object represents information stored in a graph edge, including its vertices, weight, and any extra edge info.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_WEIGHT Default weight of an edge in an undirected graph (1).

Constructor Summary

Constructors

Constructor and Description
Edge(V start, V end, E edge) Constructs information about the given edge with the default edge weight.
Edge(V start, V end, E edge, int weight) Constructs information about the given edge with the given weight.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	contains(V vertex) Returns true if this edge touches the given vertex, that is, if it is the start or end of this edge.
E	edge() Returns the extra information, if any, stored in this edge.
V	end() Returns the ending vertex of this edge.
boolean	equals(java.lang.Object o) Returns true if o refers to an Edge object with identical state to this Edge object.
int	hashCode() Returns an integer code for placing this edge into a hash-based collection.
void	setEdge(E edge) Modifies this edge's extra information to be the given value.
void	setWeight(int weight) Modifies this edge's weight to be the given value.
V	start() Returns the starting vertex of this edge.
java.lang.String	toString() Returns a string representation of the information about this edge.
int	weight() Returns the weight of this edge.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_WEIGHT

public static final int DEFAULT_WEIGHT

Default weight of an edge in an undirected graph (1).

See Also:

Constant Field Values

Constructor Detail

Edge

public Edge(V start,
    V end,
    E edge)

Constructs information about the given edge with the default edge weight.

Parameters:

start - The starting vertex of the edge.

end - The ending vertex of the edge.

edge - The extra information (if any) to store in this edge; null if none.

Throws:

java.lang.NullPointerException - If the start or end vertex is null.

Edge

public Edge(V start,
    V end,
    E edge,
    int weight)

Constructs information about the given edge with the given weight.

Parameters:

start - The starting vertex of the edge.

end - The ending vertex of the edge.

edge - The extra information (if any) to store in this edge; null if none.

weight - Edge's weight; cannot be negative. Set to 1 in an unweighted graph.

Throws:

java.lang.IllegalArgumentException - If the weight is negative.

java.lang.NullPointerException - If the start or end vertex is null.

Method Detail

contains

public boolean contains(V vertex)

Returns true if this edge touches the given vertex, that is, if it is the start or end of this edge.

Throws:

java.lang.NullPointerException - If the vertex is null.

edge

public E edge()

Returns the extra information, if any, stored in this edge. Returns null if no extra information is stored in this edge.

end

public V end()

Returns the ending vertex of this edge. In undirected graphs, the notion of "start" and "end" are ambiguous for an edge; this method always returns the second vertex that was passed to the edge's constructor.

equals

public boolean equals(java.lang.Object o)

Returns true if o refers to an Edge object with identical state to this Edge object.

Overrides:

equals in class java.lang.Object

Parameters:

o - the object to examine

hashCode

public int hashCode()

Returns an integer code for placing this edge into a hash-based collection.

Overrides:

hashCode in class java.lang.Object

setEdge

public void setEdge(E edge)

Modifies this edge's extra information to be the given value.

Parameters:

edge - The new information to use.

setWeight

public void setWeight(int weight)

Modifies this edge's weight to be the given value.

Parameters:

weight - The new weight to use.

Throws:

java.lang.IllegalArgumentException - If the weight is negative.

start

public V start()

Returns the starting vertex of this edge. In undirected graphs, the notion of "start" and "end" are ambiguous for an edge; this method always returns the first vertex that was passed to the edge's constructor.

weight

public int weight()

Returns the weight of this edge.

toString

public java.lang.String toString()

Returns a string representation of the information about this edge.

Overrides:

toString in class java.lang.Object