001    /**
002     *  Licensed to the Apache Software Foundation (ASF) under one or more
003     *  contributor license agreements.  See the NOTICE file distributed with
004     *  this work for additional information regarding copyright ownership.
005     *  The ASF licenses this file to You under the Apache License, Version 2.0
006     *  (the "License"); you may not use this file except in compliance with
007     *  the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     *  Unless required by applicable law or agreed to in writing, software
012     *  distributed under the License is distributed on an "AS IS" BASIS,
013     *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     *  See the License for the specific language governing permissions and
015     *  limitations under the License.
016     */
017    
018    package org.apache.geronimo.system.logging.log4j;
019    
020    import java.io.PrintWriter;
021    import java.io.StringWriter;
022    
023    import org.apache.log4j.helpers.FormattingInfo;
024    import org.apache.log4j.helpers.PatternConverter;
025    import org.apache.log4j.spi.LoggingEvent;
026    
027    /**
028     *
029     *
030     * @version $Rev: 706640 $ $Date: 2008-10-21 14:44:05 +0000 (Tue, 21 Oct 2008) $
031     */
032    public final class NamedNDCConverter
033            extends PatternConverter {
034        private final NamedNDC namedNDC;
035    
036        public NamedNDCConverter(FormattingInfo formattingInfo, String key) {
037            super(formattingInfo);
038            namedNDC = NamedNDC.getNamedNDC(key);
039            assert namedNDC != null;
040        }
041    
042        protected String convert(LoggingEvent loggingEvent) {
043            try {
044                Object value = namedNDC.get();
045                if (value == null) {
046                    return null;
047                }
048                return value.toString();
049            } catch (Exception e) {
050                StringWriter sw = new StringWriter();
051                PrintWriter pw = new PrintWriter(sw);
052                e.printStackTrace(pw);
053                return sw.toString();
054            }
055        }
056    }