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 */
017package org.apache.logging.log4j.core.pattern;
018
019import org.apache.logging.log4j.core.LogEvent;
020import org.apache.logging.log4j.core.config.plugins.Plugin;
021import org.apache.logging.log4j.util.PerformanceSensitive;
022
023
024/**
025 * Returns the event's NDC in a StringBuilder.
026 */
027@Plugin(name = "NdcPatternConverter", category = PatternConverter.CATEGORY)
028@ConverterKeys({"x", "NDC"})
029public final class NdcPatternConverter extends LogEventPatternConverter {
030    /**
031     * Singleton.
032     */
033    private static final NdcPatternConverter INSTANCE =
034        new NdcPatternConverter();
035
036    /**
037     * Private constructor.
038     */
039    private NdcPatternConverter() {
040        super("NDC", "ndc");
041    }
042
043    /**
044     * Obtains an instance of NdcPatternConverter.
045     *
046     * @param options options, may be null.
047     * @return instance of NdcPatternConverter.
048     */
049    public static NdcPatternConverter newInstance(final String[] options) {
050        return INSTANCE;
051    }
052
053    @Override
054    @PerformanceSensitive("allocation")
055    public void format(final LogEvent event, final StringBuilder toAppendTo) {
056        toAppendTo.append(event.getContextStack());
057    }
058}