defaultconflictresolver.java

jboss规则引擎

package org.drools.leaps.conflict;

/*
 * Copyright 2005 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.
 */

import java.util.Comparator;

import org.drools.leaps.ConflictResolver;

/**
 * Default strategy for resolving conflicts amongst multiple rules.
 * 
 * <p>
 * Since a fact or set of facts may activate multiple rules, a
 * <code>ConflictResolutionStrategy</code> is used to provide priority
 * ordering of conflicting rules.
 * </p>
 * 
 * @author Alexander Bagerman
 * 
 * @see org.drools.leaps.conflict.AbstractConflictResolver
 * @see org.drools.leaps.ConflictResolver
 * @see org.drools.spi.ConflictResolver
 */
public class DefaultConflictResolver extends CompositeConflictResolver {

    private static final Comparator[]            FACT_CONFLICT_RESOLVERS = new Comparator[]{LoadOrderConflictResolver.getInstance()};

    private static final Comparator[]            RULE_CONFLICT_RESOLVERS = new Comparator[]{RuleSalienceConflictResolver.getInstance(), RuleComplexityConflictResolver.getInstance(), LoadOrderConflictResolver.getInstance()};

    /** Singleton instance. */
    private static final DefaultConflictResolver INSTANCE                = new DefaultConflictResolver();

    /**
     * Retrieve the singleton instance.
     * 
     * @return The singleton instance.
     */
    public static ConflictResolver getInstance() {
        return DefaultConflictResolver.INSTANCE;
    }

    /**
     * Setup a default ConflictResolver configuration
     */
    public DefaultConflictResolver() {
        super( DefaultConflictResolver.FACT_CONFLICT_RESOLVERS,
               DefaultConflictResolver.RULE_CONFLICT_RESOLVERS );
    }
}