src/java/org/apache/log4j/rule/AndRule.java

/*
 * Copyright 1999,2004 The Apache Software Foundation.
 * 
 * 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.apache.log4j.rule;

import org.apache.log4j.spi.LoggingEvent;

import java.util.Stack;


/**
 * A Rule class implementing a logical 'and'.
 *
 * @author Scott Deboy <sdeboy@apache.org>
 */
public class AndRule extends AbstractRule {
  private final Rule firstRule;
  private final Rule secondRule;
  static final long serialVersionUID = -8233444426923854651L;
  
  private AndRule(Rule firstRule, Rule secondRule) {
    this.firstRule = firstRule;
    this.secondRule = secondRule;
  }

  public static Rule getRule(Stack stack) {
    if (stack.size() < 2) {
        throw new IllegalArgumentException("Invalid AND rule - expected two rules but received " + stack.size());
    }  
    Object o2 = stack.pop();
    Object o1 = stack.pop();
    if ((o2 instanceof Rule) && (o1 instanceof Rule)) { 
        Rule p2 = (Rule) o2;
        Rule p1 = (Rule) o1;
        return new AndRule(p1, p2);
    }
    throw new IllegalArgumentException("Invalid AND rule: " + o2 + "..." + o1);
  }

  public static Rule getRule(Rule firstParam, Rule secondParam) {
    return new AndRule(firstParam, secondParam);
  }

  public boolean evaluate(LoggingEvent event) {
    return (firstRule.evaluate(event) && secondRule.evaluate(event));
  }
}