    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    }