/*
 * 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.
 * <p>
 * See <a href=doc-files/MyPatternParser.java><b>source</b></a> code for more details.
 *
 * @author Anders Kristensen
 * @see org.apache.log4j.examples.MyPatternLayout
 * @see org.apache.log4j.helpers.PatternParser
 * @see org.apache.log4j.PatternLayout
 */
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);
        }
    }
}
