burlap.behavior.statehashing

Class StateHashTuple

java.lang.Object

burlap.behavior.statehashing.StateHashTuple

Direct Known Subclasses:

DiscreteStateHashFactory.DiscreteStateHashTuple, DiscretizingStateHashFactory.DiscretizedStateHashTuple, NameDependentStateHashFactory.NameDependentStateHashTuple

public abstract class StateHashTuple
extends java.lang.Object

This class provides a hash value for State objects. This is useful for tabular planning and learning algorithms that make use of hash-backed sets or maps for fast retrieval. In general, hash codes should only be computed once, and only once the hashCode method is called. If something about the StateHashTuple changes, then needsToRecomputeHashCode boolean flag should be set to true so that the next time the hashCode is called it is recomputed. Likewise, once the computeHashCode() method has been called, it should set the needToRecomputeHashCode flag to false.

By default, equality checks use the standard State object equality check. If you need to handle this specially, (such as providing state abstraction), then the equals method should be overridden.

Author:

James MacGlashan

Field Summary

Fields

Modifier and Type	Field and Description
protected int	hashCode
protected boolean	needToRecomputeHashCode
State	s

Constructor Summary

Constructors

Constructor and Description
StateHashTuple(State s) Initializes the StateHashTuple with the given State object.

Method Summary

Methods

Modifier and Type	Method and Description
abstract void	computeHashCode() This method computes the hashCode for this object and saves it to the hashCode field beloning to the abstract class.
boolean	equals(java.lang.Object other)
int	hashCode()

Methods inherited from class java.lang.Object

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

Field Detail

s

public State s

hashCode

protected int hashCode

needToRecomputeHashCode

protected boolean needToRecomputeHashCode

Constructor Detail

StateHashTuple

public StateHashTuple(State s)

Initializes the StateHashTuple with the given State object.

Parameters:

s - the state object this object will wrap

Method Detail

computeHashCode

public abstract void computeHashCode()

This method computes the hashCode for this object and saves it to the hashCode field beloning to the abstract class.

equals

public boolean equals(java.lang.Object other)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object