org.geotools.graph.path
Class Walk

Object
  AbstractCollection<E>
      AbstractList<E>
          ArrayList
              Walk

All Implemented Interfaces:

Serializable, Cloneable, Iterable, Collection, List, RandomAccess, NodeSequence

Direct Known Subclasses:

Cycle, Path

public class Walk
extends ArrayList
implements NodeSequence

Represents a walk in a graph. A walk W is defined as an ordered set of nodes that two adjacenct nodes in the set share an edge. More precisley:

G = {N,E} W = { n(i) in N | (n(i-1),n(i)) in E }

Author:

Justin Deoliveira, Refractions Research Inc, jdeolive@refractions.net

See Also:

Serialized Form

Field Summary

Fields inherited from class AbstractList

modCount

Constructor Summary

Walk()

Walk(Collection nodes)

Method Summary

void	add(int index, Object element)
boolean	add(Node node) Adds a node to the walk.
boolean	add(Object o)
boolean	addAll(Collection c)
boolean	addAll(int index, Collection c)
boolean	addEdge(Edge e)
void	addEdges(Collection edges)
protected List	buildEdges() Internal method for building the edge set of the walk.
Path	duplicate()
boolean	equals(Object other)
boolean	equals(Walk other)
List	getEdges() Calculates the edges in the walk.
Node	getFirst() Returns the first node in the sequence.
Node	getLast() Returns the last node in the sequence.
int	hashCode()
boolean	isClosed() Determines if the walk is closed.
boolean	isValid() A valid walk is one in which each pair of adjacent nodes in the sequence share an edge.
Object	remove(int index)
void	remove(Node node) Removes a node from the walk.
boolean	remove(Object o)
boolean	removeAll(Collection c)
void	reverse() Reverses the path.
Iterator	riterator() Returns an iterator that iterates over the path in reverse.
void	truncate(int index) Truncates the path at the specified index.

Methods inherited from class ArrayList

clear, clone, contains, ensureCapacity, get, indexOf, isEmpty, lastIndexOf, removeRange, set, size, toArray, toArray, trimToSize

Methods inherited from class AbstractList

iterator, listIterator, listIterator, subList

Methods inherited from class AbstractCollection

containsAll, retainAll, toString

Methods inherited from class Object

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

Methods inherited from interface NodeSequence

iterator, size

Methods inherited from interface List

containsAll, iterator, listIterator, listIterator, retainAll, subList

Constructor Detail

Walk

public Walk()

Walk

public Walk(Collection nodes)

Method Detail

isValid

public boolean isValid()

A valid walk is one in which each pair of adjacent nodes in the sequence share an edge. Note,

Specified by:

isValid in interface NodeSequence

Returns:

True if valid, otherwise false.

getEdges

public List getEdges()

Calculates the edges in the walk. If the edges of the walk cannot be calculated (due to an invalid walk), null is returned, otherwise the list of edges is returned.

Returns:

The edges of the walk, otherwise null if the edges cannot be calculated.

add

public boolean add(Node node)

Adds a node to the walk. Adding a node clears the edge list which will be recalculated on the next call to getEdges().

Parameters:

node - Node to add to the walk.

add

public void add(int index,
                Object element)

Specified by:

add in interface List

Overrides:

add in class ArrayList

add

public boolean add(Object o)

Specified by:

add in interface Collection

Specified by:

add in interface List

Overrides:

add in class ArrayList

addAll

public boolean addAll(Collection c)

Specified by:

addAll in interface Collection

Specified by:

addAll in interface List

Overrides:

addAll in class ArrayList

addAll

public boolean addAll(int index,
                      Collection c)

Specified by:

addAll in interface List

Overrides:

addAll in class ArrayList

addEdge

public boolean addEdge(Edge e)

addEdges

public void addEdges(Collection edges)

remove

public void remove(Node node)

Removes a node from the walk. Removing a node clears the edge list which will be recalculated on the next call to getEdges().

Parameters:

node - Node to remove from the walk.

remove

public Object remove(int index)

Specified by:

remove in interface List

Overrides:

remove in class ArrayList

remove

public boolean remove(Object o)

Specified by:

remove in interface Collection

Specified by:

remove in interface List

Overrides:

remove in class ArrayList

removeAll

public boolean removeAll(Collection c)

Specified by:

removeAll in interface Collection

Specified by:

removeAll in interface List

Overrides:

removeAll in class AbstractCollection

isClosed

public boolean isClosed()

Determines if the walk is closed. A closed walk is one in which the first and last nodes are the same.

Returns:

True if closed, otherwise false.

getFirst

public Node getFirst()

Description copied from interface: NodeSequence

Returns the first node in the sequence.

Specified by:

getFirst in interface NodeSequence

Returns:

Object of tupe Node.

See Also:

NodeSequence.getFirst()

getLast

public Node getLast()

Description copied from interface: NodeSequence

Returns the last node in the sequence.

Specified by:

getLast in interface NodeSequence

Returns:

Object of type node.

See Also:

NodeSequence.getLast()

buildEdges

protected List buildEdges()

Internal method for building the edge set of the walk. This method calculated the edges upon every call.

Returns:

The list of edges for the walk, or null if the edge set could not be calculated due to an invalid walk.

reverse

public void reverse()

Reverses the path.

truncate

public void truncate(int index)

Truncates the path at the specified index. Nodes in the path whose index is >= the specified index are removed.

Parameters:

index - The index of first node to be removed.

riterator

public Iterator riterator()

Returns an iterator that iterates over the path in reverse. The iterator does not support the remove operation.

Returns:

the reverse iterator.

duplicate

public Path duplicate()

equals

public boolean equals(Object other)

Specified by:

equals in interface Collection

Specified by:

equals in interface List

Overrides:

equals in class AbstractList

equals

public boolean equals(Walk other)

hashCode

public int hashCode()

Specified by:

hashCode in interface Collection

Specified by:

hashCode in interface List

Overrides:

hashCode in class AbstractList