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Drools Planner optimizes automated planning by combining metaheuristic search algorithms with rule
engine powered score calculation. This is the drools-planner-core module which contains metaheuristic
algorithms.
/*
* Copyright 2011 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.constructionheuristic.greedyFit;
import java.util.Iterator;
import org.drools.planner.core.constructionheuristic.greedyFit.decider.GreedyDecider;
import org.drools.planner.core.constructionheuristic.greedyFit.selector.GreedyPlanningEntitySelector;
import org.drools.planner.core.move.Move;
import org.drools.planner.core.phase.AbstractSolverPhase;
import org.drools.planner.core.solver.DefaultSolverScope;
/**
* Default implementation of {@link GreedyFitSolverPhase}.
*/
public class DefaultGreedyFitSolverPhase extends AbstractSolverPhase implements GreedyFitSolverPhase {
protected GreedyPlanningEntitySelector greedyPlanningEntitySelector;
protected GreedyDecider greedyDecider;
protected boolean assertStepScoreIsUncorrupted = false;
public void setGreedyPlanningEntitySelector(GreedyPlanningEntitySelector greedyPlanningEntitySelector) {
this.greedyPlanningEntitySelector = greedyPlanningEntitySelector;
}
public void setGreedyDecider(GreedyDecider greedyDecider) {
this.greedyDecider = greedyDecider;
}
public void setAssertStepScoreIsUncorrupted(boolean assertStepScoreIsUncorrupted) {
this.assertStepScoreIsUncorrupted = assertStepScoreIsUncorrupted;
}
// ************************************************************************
// Worker methods
// ************************************************************************
public void solve(DefaultSolverScope solverScope) {
GreedyFitSolverPhaseScope solverPhaseScope = new GreedyFitSolverPhaseScope(solverScope);
phaseStarted(solverPhaseScope);
GreedyFitStepScope stepScope = createNextStepScope(solverPhaseScope, null);
Iterator it = greedyPlanningEntitySelector.iterator();
while (!termination.isPhaseTerminated(solverPhaseScope) && it.hasNext()) {
Object planningEntity = it.next();
stepScope.setPlanningEntity(planningEntity);
beforeDeciding(stepScope);
greedyDecider.decideNextStep(stepScope);
Move nextStep = stepScope.getStep();
if (nextStep == null) {
logger.warn(" Cancelled step index ({}), time spend ({}): there is no doable move. Terminating phase early.",
stepScope.getStepIndex(),
solverPhaseScope.calculateSolverTimeMillisSpend());
break;
}
nextStep.doMove(stepScope.getScoreDirector());
// there is no need to recalculate the score, but we still need to set it
solverPhaseScope.getWorkingSolution().setScore(stepScope.getScore());
if (assertStepScoreIsUncorrupted) {
solverPhaseScope.assertWorkingScore(stepScope.getScore());
}
if (!it.hasNext()) {
stepScope.setSolutionInitialized(true);
}
stepTaken(stepScope);
stepScope = createNextStepScope(solverPhaseScope, stepScope);
}
phaseEnded(solverPhaseScope);
}
private GreedyFitStepScope createNextStepScope(GreedyFitSolverPhaseScope greedyFitSolverPhaseScope, GreedyFitStepScope completedGreedyFitStepScope) {
if (completedGreedyFitStepScope == null) {
completedGreedyFitStepScope = new GreedyFitStepScope(greedyFitSolverPhaseScope);
completedGreedyFitStepScope.setScore(greedyFitSolverPhaseScope.getStartingScore());
completedGreedyFitStepScope.setStepIndex(-1);
}
greedyFitSolverPhaseScope.setLastCompletedGreedyFitStepScope(completedGreedyFitStepScope);
GreedyFitStepScope greedyFitStepScope = new GreedyFitStepScope(greedyFitSolverPhaseScope);
greedyFitStepScope.setStepIndex(completedGreedyFitStepScope.getStepIndex() + 1);
greedyFitStepScope.setSolutionInitialized(false);
return greedyFitStepScope;
}
public void phaseStarted(GreedyFitSolverPhaseScope greedyFitSolverPhaseScope) {
super.phaseStarted(greedyFitSolverPhaseScope);
greedyPlanningEntitySelector.phaseStarted(greedyFitSolverPhaseScope);
greedyDecider.phaseStarted(greedyFitSolverPhaseScope);
}
public void beforeDeciding(GreedyFitStepScope greedyFitStepScope) {
super.beforeDeciding(greedyFitStepScope);
greedyPlanningEntitySelector.beforeDeciding(greedyFitStepScope);
greedyDecider.beforeDeciding(greedyFitStepScope);
}
public void stepTaken(GreedyFitStepScope greedyFitStepScope) {
super.stepTaken(greedyFitStepScope);
greedyPlanningEntitySelector.stepTaken(greedyFitStepScope);
greedyDecider.stepTaken(greedyFitStepScope);
logger.debug(" Step index ({}), time spend ({}), score ({}), initialized planning entity ({}).",
new Object[]{greedyFitStepScope.getStepIndex(),
greedyFitStepScope.getGreedyFitSolverPhaseScope().calculateSolverTimeMillisSpend(),
greedyFitStepScope.getScore(),
greedyFitStepScope.getPlanningEntity()});
}
public void phaseEnded(GreedyFitSolverPhaseScope greedyFitSolverPhaseScope) {
super.phaseEnded(greedyFitSolverPhaseScope);
greedyPlanningEntitySelector.phaseEnded(greedyFitSolverPhaseScope);
greedyDecider.phaseEnded(greedyFitSolverPhaseScope);
logger.info("Phase constructionHeuristic ended: step total ({}), time spend ({}), best score ({}).",
new Object[]{greedyFitSolverPhaseScope.getLastCompletedStepScope().getStepIndex() + 1,
greedyFitSolverPhaseScope.calculateSolverTimeMillisSpend(),
greedyFitSolverPhaseScope.getBestScore()});
}
}