ps3.graph
Class NodeCountingPath

java.lang.Object
  ps3.graph.NodeCountingPath

All Implemented Interfaces:

Comparable<Path<?,?>>, Iterable<WeightedNode>, Path<WeightedNode,NodeCountingPath>

public class NodeCountingPath
extends Object
implements Path<WeightedNode,NodeCountingPath>

A NodeCountingPath characterizes a path of WeightedNodes. The cost for a path is the number of WeightedNodes it contains; the cost of the WeightedNodes are ignored.

A NodeCountingPath is immutable. A new NodeCountingPath is returned through the extend path operation.

The main purpose of this class is to illustrate that there can be multiple implementations of Paths of WeightedNodes.

Specfields inherited from Path:

Specification Fields

• cost - : double // cost of traversing this path.
• elements - : sequence // sequence of nodes in this path.

Constructor Summary

NodeCountingPath(WeightedNode node)
Constructs a NodeCountingPath containing one node.

Method Summary

int	compareTo(Path<?,?> p) Compares the cost of this path to the given path.
double	cost()
WeightedNode	end() Return the end of this path
boolean	equals(NodeCountingPath wnp)
boolean	equals(Object o)
NodeCountingPath	extend(WeightedNode node) Creates an extended path by adding a new node to its end.
int	hashCode()
Iterator<WeightedNode>	iterator()
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

NodeCountingPath

public NodeCountingPath(WeightedNode node)

Constructs a NodeCountingPath containing one node.

Requires:

node != null

Effects:

Creates a new NodeCountingPath which originates at node.

Method Detail

extend

public NodeCountingPath extend(WeightedNode node)

Description copied from interface: Path

Creates an extended path by adding a new node to its end.

Specified by:

extend in interface Path<WeightedNode,NodeCountingPath>

Returns:

a new Path p such that p.elements = this.elements + [ n ] && p.cost >= this.cost

cost

public double cost()

Specified by:

cost in interface Path<WeightedNode,NodeCountingPath>

Returns:

this.cost

iterator

public Iterator<WeightedNode> iterator()

Specified by:

iterator in interface Iterable<WeightedNode>

Specified by:

iterator in interface Path<WeightedNode,NodeCountingPath>

Returns:

an Iterator over the elements in the path in order from start to end.

toString

public String toString()

Overrides:

toString in class Object

Returns:

a string representation of this.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

Returns:

true iff o is a NodeCountingPath and o.elements is the same sequence as this.elements

equals

public boolean equals(NodeCountingPath wnp)

Returns:

true iff wnp.elements is the same sequence as this.elements

hashCode

public int hashCode()

Overrides:

hashCode in class Object

Returns:

a valid hashcode for this.

compareTo

public int compareTo(Path<?,?> p)

Compares the cost of this path to the given path.

Specified by:

compareTo in interface Comparable<Path<?,?>>

Returns:

the value 0 if the cost of this path is equal to the cost of the given path; a value less than 0 if this.cost is less than p.cost; and a value greater than 0 if this.cost is greater than p.cost.

See Also:

Comparable.compareTo(T)

end

public WeightedNode end()

Return the end of this path

Specified by:

end in interface Path<WeightedNode,NodeCountingPath>

Returns:

the end of the path