org.jamesframework.core.search.cache

Class SingleEvaluatedMoveCache

java.lang.Object

org.jamesframework.core.search.cache.SingleEvaluatedMoveCache

All Implemented Interfaces:

EvaluatedMoveCache

public class SingleEvaluatedMoveCache
extends Object
implements EvaluatedMoveCache

A single move cache only stores the last evaluation and validation that were offered to the cache. Any previously cached value is immediately discarded and replaced with the new value. In general, most neighbourhood searches select a single candidate move (random, best, ...) from the neighbourhood in every step and then just decide whether or not to apply it to the current solution. Therefore, a single move cache can be used to effectively cache the evaluation and validation of this candidate move with minor memory overhead.

This is the default cache of any neighbourhood search.

Author:

Herman De Beukelaer

Constructor Summary

Constructors

Constructor and Description
SingleEvaluatedMoveCache() Create an empty single evaluated move cache.

Method Summary

Modifier and Type	Method and Description
void	cacheMoveEvaluation(Move<?> move, Evaluation evaluation) Cache the given evaluation, discarding any previously cached evaluations.
void	cacheMoveValidation(Move<?> move, Validation validation) Cache validation of the given move, discarding any previously cached value.
void	clear() Clear all cached values.
Evaluation	getCachedMoveEvaluation(Move<?> move) Retrieve a cached evaluation, if still available.
Validation	getCachedMoveValidation(Move<?> move) Retrieve a cached validation, if still available.

Methods inherited from class java.lang.Object

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

Constructor Detail

SingleEvaluatedMoveCache

public SingleEvaluatedMoveCache()

Create an empty single evaluated move cache.

Method Detail

cacheMoveEvaluation

public final void cacheMoveEvaluation(Move<?> move,
                                      Evaluation evaluation)

Cache the given evaluation, discarding any previously cached evaluations.

Specified by:

cacheMoveEvaluation in interface EvaluatedMoveCache

Parameters:

move - move applied to the current solution

evaluation - evaluation of obtained neighbour

getCachedMoveEvaluation

public final Evaluation getCachedMoveEvaluation(Move<?> move)

Retrieve a cached evaluation, if still available. If the evaluation of any other move has been cached at a later point in time, the value for this move will have been overwritten.

Specified by:

getCachedMoveEvaluation in interface EvaluatedMoveCache

Parameters:

move - move applied to the current solution

Returns:

cached evaluation of the obtained neighbour, if available, null if not

cacheMoveValidation

public final void cacheMoveValidation(Move<?> move,
                                      Validation validation)

Cache validation of the given move, discarding any previously cached value.

Specified by:

cacheMoveValidation in interface EvaluatedMoveCache

Parameters:

move - move applied to the current solution

validation - validation of obtained neighbour

getCachedMoveValidation

public final Validation getCachedMoveValidation(Move<?> move)

Retrieve a cached validation, if still available. If the validation of any other move has been cached at a later point in time, the value for this move will have been overwritten.

Specified by:

getCachedMoveValidation in interface EvaluatedMoveCache

Parameters:

move - move applied to the current solution

Returns:

cached validation of the obtained neighbour, if available, null if not

clear

public final void clear()

Clear all cached values.

Specified by:

clear in interface EvaluatedMoveCache