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    package org.apache.logging.log4j.core.pattern;
018    
019    import org.apache.logging.log4j.core.LogEvent;
020    import org.apache.logging.log4j.core.config.plugins.Plugin;
021    
022    
023    /**
024     * Returns the event's NDC in a StringBuilder.
025     */
026    @Plugin(name = "NdcPatternConverter", category = PatternConverter.CATEGORY)
027    @ConverterKeys({ "x", "NDC" })
028    public final class NdcPatternConverter extends LogEventPatternConverter {
029      /**
030       *   Singleton.
031       */
032      private static final NdcPatternConverter INSTANCE =
033        new NdcPatternConverter();
034    
035      /**
036       * Private constructor.
037       */
038      private NdcPatternConverter() {
039        super("NDC", "ndc");
040      }
041    
042      /**
043       * Obtains an instance of NdcPatternConverter.
044       * @param options options, may be null.
045       * @return instance of NdcPatternConverter.
046       */
047      public static NdcPatternConverter newInstance(final String[] options) {
048        return INSTANCE;
049      }
050    
051      /**
052       * {@inheritDoc}
053       */
054      @Override
055    public void format(final LogEvent event, final StringBuilder toAppendTo) {
056        toAppendTo.append(event.getContextStack());
057      }
058    }