DroolsScoreDirectorFactory.java

/*
 * Copyright 2012 Red Hat, Inc. and/or its affiliates.
 *
 * 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.optaplanner.core.impl.score.director.drools;

import org.kie.api.KieBase;
import org.kie.api.builder.model.KieSessionModel;
import org.kie.api.definition.KiePackage;
import org.kie.api.definition.rule.Global;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
import org.optaplanner.core.api.domain.solution.PlanningSolution;
import org.optaplanner.core.impl.domain.solution.descriptor.SolutionDescriptor;
import org.optaplanner.core.impl.score.director.AbstractScoreDirectorFactory;
import org.optaplanner.core.impl.score.director.ScoreDirectorFactory;

/**
 * Drools implementation of {@link ScoreDirectorFactory}.
 * @param <Solution_> the solution type, the class with the {@link PlanningSolution} annotation
 * @see DroolsScoreDirector
 * @see ScoreDirectorFactory
 */
public class DroolsScoreDirectorFactory<Solution_> extends AbstractScoreDirectorFactory<Solution_> {

    protected final KieContainer kieContainer;
    protected final String ksessionName;

    /**
     * For {@link LegacyDroolsScoreDirectorFactory} only. Do not use.
     * @param kieBase never null
     */
    protected DroolsScoreDirectorFactory(KieBase kieBase) {
        kieContainer = null;
        ksessionName = null;
    }

    /**
     * @param kieContainer never null
     * @param ksessionName null if the default ksession should be used
     */
    public DroolsScoreDirectorFactory(KieContainer kieContainer, String ksessionName) {
        this.kieContainer = kieContainer;
        this.ksessionName = ksessionName;
        // if ksessionName is null, then the default kieSession is used
        KieSessionModel kieSessionModel = kieContainer.getKieSessionModel(ksessionName);
        if (kieSessionModel == null) {
            if (ksessionName == null) {
                throw new IllegalArgumentException("The kieContainer does not have a default ksession"
                        + " and the ksessionName (" + ksessionName + ") is not specified.");
            } else {
                throw new IllegalArgumentException("The kieContainer does not contain a ksessionName ("
                        + ksessionName + ") with that name.");
            }
        }
        if (kieSessionModel.getType() != KieSessionModel.KieSessionType.STATEFUL) {
            throw new IllegalStateException("The ksessionName (" + ksessionName
                    + ") with type (" + kieSessionModel.getType() + ") is not stateful.\n"
                    + "Stateless sessions are not allowed because they don't support incremental score calculation"
                    + " and are therefore exponentially slower.");
        }
        String kbaseName = kieSessionModel.getKieBaseModel().getName();
        KieBase kieBase = kieContainer.newKieBase(kbaseName, null);
        checkIfGlobalScoreHolderExists(kieBase);
    }

    protected void checkIfGlobalScoreHolderExists(KieBase kieBase) {
        boolean hasGlobalScoreHolder = false;
        for (KiePackage kiePackage : kieBase.getKiePackages()) {
            for (Global global : kiePackage.getGlobalVariables()) {
                if (DroolsScoreDirector.GLOBAL_SCORE_HOLDER_KEY.equals(global.getName())) {
                    hasGlobalScoreHolder = true;
                    // TODO Fail fast once global.getType() can be turned into a Class instead of a String
//                    if (!ScoreHolder.class.isAssignableFrom(global.getType())) {
//                        throw new IllegalStateException("The global with name (" + global.getName()
//                                + ") has a type (" + global.getType()
//                                + ") that does not implement " + ScoreHolder.class.getSimpleName() + ".");
//                    }
                    break;
                }
            }
        }
        if (!hasGlobalScoreHolder) {
            throw new IllegalArgumentException("The kieBase with kiePackages (" + kieBase.getKiePackages()
                    + ") has no global field called " + DroolsScoreDirector.GLOBAL_SCORE_HOLDER_KEY + ".\n"
                    + "Check if the rule files are found and if the global field is spelled correctly.");
        }
    }

    @Override
    public void setSolutionDescriptor(SolutionDescriptor<Solution_> solutionDescriptor) {
        super.setSolutionDescriptor(solutionDescriptor);
        solutionDescriptor.checkIfProblemFactsExist();
    }

    public KieContainer getKieContainer() {
        return kieContainer;
    }

    /**
     * @return null if the default ksession should be used
     */
    public String getKsessionName() {
        return ksessionName;
    }

    // ************************************************************************
    // Complex methods
    // ************************************************************************

    @Override
    public DroolsScoreDirector<Solution_> buildScoreDirector(
            boolean lookUpEnabled, boolean constraintMatchEnabledPreference) {
        return new DroolsScoreDirector<>(this, lookUpEnabled, constraintMatchEnabledPreference);
    }

    public KieSession newKieSession() {
        return kieContainer.newKieSession(ksessionName);
    }

}