AbstractSearchNode (Java Search Library API)

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net.sourceforge.jsl
Class AbstractSearchNode

java.lang.Object
  |
  +--net.sourceforge.jsl.AbstractSearchNode

All Implemented Interfaces:: SearchNode

public abstract class AbstractSearchNode
extends Object
implements SearchNode

Adapter of the search library to the domain the search is performed in. You will have to subclass this class to at least provide information about the depth and the breadth of a node in a the search graph. Additionally, the cost associated to a specific node - which by default results to its depth - and the estimated rest cost - default is 0 - can be overloaded.
The most important is to implement mehod is expand(). Only the domain knows what nodes may follow another one, so you will have to implement this method accordingly.
Finally, getPath() will have to be implemented to return the path from the seed to a this search node. While this path has to be recorded inside the expand() method you can use linkForward(java.lang.Object, net.sourceforge.jsl.SearchNode) and linkBackward(java.lang.Object, net.sourceforge.jsl.SearchNode) as helper methods.
To actually spit out the path you getPath() implementation can use getFirstPathIn() and getFirstPathOut().
Which of the methods to use depends on what type the seed of the search is. If it is a leaf and you simply search the root your domain, you should use linkBackward(java.lang.Object, net.sourceforge.jsl.SearchNode) in conjunction with getFirstPathOut(). If you start the search with the seed being the root of your domain you should rather use linkForward(java.lang.Object, net.sourceforge.jsl.SearchNode) and getFirstPathIn().

Constructor Summary

AbstractSearchNode()


Method Summary

boolean cutoff()
          Indicates if this node should be pruned, i.e. excluded from further calculations.

static void dumpPath(List path)
          Helper method to dump a path to stdout.

static void dumpPath(PrintStream ps, List path)
          Helper method to dump a path to the specified print stream.

boolean equals(Object o)


abstract Collection expand()
          Expands this node and returns the search nodes following this one.

abstract int getBreadth()
          Returns the breadth of this node in the search graph (tree).

double getCost()
          Gets the cost it has taken to get to this node.

abstract int getDepth()
          Returns the depth of this node in the search graph (tree).

Object getDomainObject()
          Gets the domain object associated to this search node.

double getEstimatedRestCost()
          Estimates the cost expected to need to reach a goal from this node.

protected List getFirstPathIn()
          Returns the first path that leads from this node to the seed of this search while seed is seen as the root of the search.

protected List getFirstPathOut()
          Returns the first path that leads from this node to the seed of this search while seed is seen as a leaf of the search.

Collection getIncomingEdges()
          Gets all incoming edges.

Collection getOutgoingEdges()
          Gets all outgoing edges.

abstract List getPath()


int hashCode()


protected void linkBackward(Object edgeDomainObject, SearchNode previousSearchNode)
          Creates a new edge between this node and the specified predecessor.

protected void linkForward(Object edgeDomainObject, SearchNode nextSearchNode)
          Creates a new edge between this node and the specified successor.

void setDomainObject(Object domainObject)
          Sets the domain object associated to this search node.

void setIncomingEdges(Collection incomingEdges)
          Sets the incoming edges.

void setOutgoingEdges(Collection outgoingEdges)
          Sets the outgoing edges.

String toString()


Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sourceforge.jsl.SearchNode

isGoal

Constructor Detail

AbstractSearchNode

public AbstractSearchNode()

Method Detail

dumpPath

public static void dumpPath(List path)

Helper method to dump a path to stdout.

dumpPath

public static void dumpPath(PrintStream ps,
                            List path)

Helper method to dump a path to the specified print stream.