/*
 * 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;

import org.apache.log4j.helpers.FormattingInfo;
import org.apache.log4j.helpers.PatternConverter;
import org.apache.log4j.helpers.PatternParser;
import org.apache.log4j.spi.LoggingEvent;

/**
 * Example showing how to extend PatternParser to recognize additional
 * conversion characters. The examples shows that minimum and maximum width and
 * alignment settings apply for "extension" conversion characters just as they
 * do for PatternLayout recognized characters.
 * 
 * <p>
 * In this case MyPatternParser recognizes %# and outputs the value of an
 * internal counter which is also incremented at each call.
 * 
 * See <a href=doc-files/MyPatternParser.java><b>source</b></a> code for more
 * details.
 * 
 * @see org.apache.log4j.examples.MyPatternLayout
 * @see org.apache.log4j.helpers.PatternParser
 * @see org.apache.log4j.PatternLayout
 * 
 * @author Anders Kristensen
 */
public class MyPatternParser extends PatternParser {

    int counter = 0;

    public MyPatternParser(String pattern) {
	super(pattern);
    }

    public void finalizeConverter(char c) {
	if (c == '#') {
	    addConverter(new UserDirPatternConverter(formattingInfo));
	    currentLiteral.setLength(0);
	} else {
	    super.finalizeConverter(c);
	}
    }

    private class UserDirPatternConverter extends PatternConverter {
	UserDirPatternConverter(FormattingInfo formattingInfo) {
	    super(formattingInfo);
	}

	public String convert(LoggingEvent event) {
	    return String.valueOf(++counter);
	}
    }
}
