/*
* Copyright 2010 JBoss Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.drools.planner.core.localsearch.decider.forager;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import org.drools.planner.core.localsearch.scope.LocalSearchMoveScope;
import org.drools.planner.core.localsearch.scope.LocalSearchSolverPhaseScope;
import org.drools.planner.core.localsearch.scope.LocalSearchStepScope;
import org.drools.planner.core.localsearch.decider.acceptor.Acceptor;
import org.drools.planner.core.localsearch.decider.deciderscorecomparator.DeciderScoreComparatorFactory;
import org.drools.planner.core.score.Score;
/**
* An AcceptedForager is a Forager which forages accepted moves and ignores unaccepted moves.
* @see Forager
* @see Acceptor
*/
public class AcceptedForager extends AbstractForager {
protected DeciderScoreComparatorFactory deciderScoreComparatorFactory;
// final to allow better hotspot optimization. TODO prove that it indeed makes a difference
protected final PickEarlyType pickEarlyType;
protected final int minimalAcceptedSelection;
protected Comparator<Score> scoreComparator;
protected long selectedMoveCount;
protected long acceptedMoveCount;
protected List<LocalSearchMoveScope> maxScoreAcceptedList;
protected Score maxAcceptedScore;
protected List<LocalSearchMoveScope> maxScoreUnacceptedList;
protected Score maxUnacceptedScore;
protected LocalSearchMoveScope earlyPickedMoveScope;
public AcceptedForager(PickEarlyType pickEarlyType, int minimalAcceptedSelection) {
this.pickEarlyType = pickEarlyType;
this.minimalAcceptedSelection = minimalAcceptedSelection;
if (minimalAcceptedSelection < 1) {
throw new IllegalArgumentException("The minimalAcceptedSelection (" + minimalAcceptedSelection
+ ") cannot be negative or zero.");
}
}
public void setDeciderScoreComparatorFactory(DeciderScoreComparatorFactory deciderScoreComparator) {
this.deciderScoreComparatorFactory = deciderScoreComparator;
}
// ************************************************************************
// Worker methods
// ************************************************************************
@Override
public void phaseStarted(LocalSearchSolverPhaseScope phaseScope) {
deciderScoreComparatorFactory.phaseStarted(phaseScope);
}
@Override
public void stepStarted(LocalSearchStepScope stepScope) {
deciderScoreComparatorFactory.stepStarted(stepScope);
scoreComparator = deciderScoreComparatorFactory.createDeciderScoreComparator();
selectedMoveCount = 0L;
acceptedMoveCount = 0L;
maxScoreAcceptedList = new ArrayList<LocalSearchMoveScope>(1024);
maxAcceptedScore = stepScope.getPhaseScope().getScoreDefinition().getPerfectMinimumScore();
maxScoreUnacceptedList = new ArrayList<LocalSearchMoveScope>(1024);
maxUnacceptedScore = stepScope.getPhaseScope().getScoreDefinition().getPerfectMinimumScore();
earlyPickedMoveScope = null;
}
public boolean supportsNeverEndingMoveSelector() {
// TODO FIXME magical value Integer.MAX_VALUE coming from ForagerConfig
return minimalAcceptedSelection < Integer.MAX_VALUE;
}
public void addMove(LocalSearchMoveScope moveScope) {
selectedMoveCount++;
if (moveScope.getAccepted()) {
acceptedMoveCount++;
checkPickEarly(moveScope);
addToMaxScoreAcceptedList(moveScope);
maxScoreUnacceptedList = null;
} else if (acceptedMoveCount == 0L) {
addToMaxScoreUnacceptedList(moveScope);
}
}
protected void checkPickEarly(LocalSearchMoveScope moveScope) {
switch (pickEarlyType) {
case NEVER:
break;
case FIRST_BEST_SCORE_IMPROVING:
Score bestScore = moveScope.getStepScope().getPhaseScope().getBestScore();
if (scoreComparator.compare(moveScope.getScore(), bestScore) > 0) {
earlyPickedMoveScope = moveScope;
}
break;
case FIRST_LAST_STEP_SCORE_IMPROVING:
Score lastStepScore = moveScope.getStepScope().getPhaseScope()
.getLastCompletedStepScope().getScore();
if (scoreComparator.compare(moveScope.getScore(), lastStepScore) > 0) {
earlyPickedMoveScope = moveScope;
}
break;
default:
throw new IllegalStateException("The pickEarlyType (" + pickEarlyType + ") is not implemented");
}
}
protected void addToMaxScoreAcceptedList(LocalSearchMoveScope moveScope) {
if (scoreComparator.compare(moveScope.getScore(), maxAcceptedScore) > 0) {
maxAcceptedScore = moveScope.getScore();
maxScoreAcceptedList.clear();
maxScoreAcceptedList.add(moveScope);
} else if (moveScope.getScore().equals(maxAcceptedScore)) {
maxScoreAcceptedList.add(moveScope);
}
}
protected void addToMaxScoreUnacceptedList(LocalSearchMoveScope moveScope) {
if (scoreComparator.compare(moveScope.getScore(), maxUnacceptedScore) > 0) {
maxUnacceptedScore = moveScope.getScore();
maxScoreUnacceptedList.clear();
maxScoreUnacceptedList.add(moveScope);
} else if (moveScope.getScore().equals(maxUnacceptedScore)) {
maxScoreUnacceptedList.add(moveScope);
}
}
public boolean isQuitEarly() {
return earlyPickedMoveScope != null || acceptedMoveCount >= minimalAcceptedSelection;
}
public LocalSearchMoveScope pickMove(LocalSearchStepScope stepScope) {
stepScope.setSelectedMoveCount(selectedMoveCount);
stepScope.setAcceptedMoveCount(acceptedMoveCount);
if (earlyPickedMoveScope != null) {
return earlyPickedMoveScope;
} else {
return pickMaxScoreMoveScope(stepScope);
}
}
protected LocalSearchMoveScope pickMaxScoreMoveScope(LocalSearchStepScope stepScope) {
List<LocalSearchMoveScope> maxScoreList;
if (maxScoreAcceptedList.isEmpty()) {
if (maxScoreUnacceptedList.isEmpty()) {
return null;
} else {
maxScoreList = maxScoreUnacceptedList;
}
} else {
maxScoreList = maxScoreAcceptedList;
}
if (maxScoreList.size() == 1) {
return maxScoreList.get(0);
}
int randomIndex = stepScope.getWorkingRandom().nextInt(maxScoreList.size());
return maxScoreList.get(randomIndex);
}
@Override
public void stepEnded(LocalSearchStepScope stepScope) {
deciderScoreComparatorFactory.stepEnded(stepScope);
}
@Override
public void phaseEnded(LocalSearchSolverPhaseScope phaseScope) {
deciderScoreComparatorFactory.phaseEnded(phaseScope);
}
@Override
public String toString() {
return getClass().getSimpleName() + "(" + pickEarlyType + ", " + minimalAcceptedSelection + ")";
}
}