stanford.cs106.collections

Class Edge<V,E>

java.lang.Object

stanford.cs106.collections.Edge<V,E>

All Implemented Interfaces:

Cloneable

public class Edge<V,E>
extends Object
implements Cloneable

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).
E	extraData

Constructor Summary

Constructors

Constructor and Description
Edge(Vertex<V> start, Vertex<V> end) Constructs information about the given edge with the default edge weight.
Edge(Vertex<V> start, Vertex<V> end, double weight) Constructs information about the given edge with the default edge weight.

Method Summary

Modifier and Type	Method and Description
Edge<V,E>	clone() Returns a copy of this Edge as per the contract of the Object.clone method.
boolean	contains(Vertex<V> vertex) Returns true if this edge touches the given vertex, that is, if it is the start or end of this edge.
double	cost() Returns the weight of this edge.
Vertex<V>	end() Returns the ending vertex of this edge.
boolean	equals(Object o) Returns true if o refers to an Edge object with identical state to this Edge object.
Vertex<V>	finish() Returns the ending vertex of this edge.
int	hashCode() Returns an integer code for placing this edge into a hash-based collection.
void	setWeight(double weight) Modifies this edge's weight to be the given value.
Vertex<V>	start() Returns the starting vertex of this edge.
String	toString() Returns a string representation of the information about this edge.
double	weight() Returns the weight of this edge.

Methods inherited from class java.lang.Object

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

extraData

public E extraData

Constructor Detail

Edge

public Edge(Vertex<V> start,
            Vertex<V> end)

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:

NullPointerException - If the start or end vertex is null.

Edge

public Edge(Vertex<V> start,
            Vertex<V> end,
            double weight)

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:

NullPointerException - If the start or end vertex is null.

Method Detail

clone

public Edge<V,E> clone()

Returns a copy of this Edge as per the contract of the Object.clone method.

Overrides:

clone in class Object

contains

public boolean contains(Vertex<V> vertex)

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

Throws:

NullPointerException - If the vertex is null.

cost

public double cost()

Returns the weight of this edge.

end

public Vertex<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(Object o)

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

Overrides:

equals in class Object

Parameters:

o - the object to examine

finish

public Vertex<V> finish()

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.

hashCode

public int hashCode()

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

Overrides:

hashCode in class Object

setWeight

public void setWeight(double weight)

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

Parameters:

weight - The new weight to use.

Throws:

IllegalArgumentException - If the weight is negative.

start

public Vertex<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 double weight()

Returns the weight of this edge.

toString

public String toString()

Returns a string representation of the information about this edge.

Overrides:

toString in class Object