/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.log4j.chainsaw;

import org.apache.log4j.rule.AbstractRule;
import org.apache.log4j.rule.Rule;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.Map;
import org.apache.log4j.chainsaw.logevents.ChainsawLoggingEvent;


/**
 * A mediator class that implements the Rule interface, by combining several
 * optional rules used by Chainsaw's filtering GUI's into a single Rule.
 * <p>
 * <p>Setting the individual sub-rules propagates a PropertyChangeEvent as per
 * standard Java beans principles.
 *
 * @author Paul Smith &lt;psmith@apache.org&gt;
 * @author Scott Deboy &lt;sdeboy@apache.org&gt;
 */
public class RuleMediator extends AbstractRule {
    private Rule loggerRule;
    private Rule filterRule;
    private Rule findRule;
    private final PropertyChangeListener ruleChangerNotifier = new RuleChangerNotifier();
    private boolean findRuleRequired;

    public RuleMediator(boolean findRuleRequired) {
        this.findRuleRequired = findRuleRequired;
    }

    /* (non-Javadoc)
     * @see org.apache.log4j.chainsaw.rule.Rule#evaluate(org.apache.log4j.spi.LoggingEvent)
     */
    public boolean evaluate(ChainsawLoggingEvent e, Map matches) {
        if (findRuleRequired) {
            if (findRule == null) {
                return false;
            }
            if (!findRule.evaluate(e, null)) {
                return false;
            }
        }

        return (loggerRule == null || loggerRule.evaluate(e, null)) && (filterRule == null || filterRule.evaluate(e, null));

    }

    public boolean isFindRuleRequired() {
        return findRuleRequired;
    }

    public void setFilterRule(Rule r) {
        Rule oldFilterRule = this.filterRule;
        this.filterRule = r;
        firePropertyChange("filterRule", oldFilterRule, this.filterRule);
    }

    public void setFindRule(Rule r) {
        Rule oldFindRule = this.findRule;
        this.findRule = r;
        firePropertyChange("findRule", oldFindRule, this.findRule);
    }

    public void setLoggerRule(Rule r) {
        Rule oldLoggerRule = this.loggerRule;
        this.loggerRule = r;
        if (oldLoggerRule != null) {
            oldLoggerRule.removePropertyChangeListener(ruleChangerNotifier);
        }
        this.loggerRule.addPropertyChangeListener(ruleChangerNotifier);
        firePropertyChange("loggerRule", oldLoggerRule, this.loggerRule);
    }

    /**
     * Helper class that propagates internal Rules propertyChange events
     * to external parties, since an internal rule changing really means
     * this outter rule is going to change too.
     */
    private class RuleChangerNotifier implements PropertyChangeListener {
        /* (non-Javadoc)
         * @see java.beans.PropertyChangeListener#propertyChange(java.beans.PropertyChangeEvent)
         */
        public void propertyChange(PropertyChangeEvent evt) {
            RuleMediator.this.firePropertyChange(evt);
        }
    }
}