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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements. See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache license, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License. You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the license for the specific language governing permissions and
15   * limitations under the license.
16   */
17  package org.apache.logging.log4j.core.pattern;
18  
19  import org.apache.logging.log4j.core.LogEvent;
20  import org.apache.logging.log4j.core.config.plugins.Plugin;
21  import org.apache.logging.log4j.util.PerformanceSensitive;
22  
23  
24  /**
25   * Returns the event's NDC in a StringBuilder.
26   */
27  @Plugin(name = "NdcPatternConverter", category = PatternConverter.CATEGORY)
28  @ConverterKeys({"x", "NDC"})
29  public final class NdcPatternConverter extends LogEventPatternConverter {
30      /**
31       * Singleton.
32       */
33      private static final NdcPatternConverter INSTANCE =
34          new NdcPatternConverter();
35  
36      /**
37       * Private constructor.
38       */
39      private NdcPatternConverter() {
40          super("NDC", "ndc");
41      }
42  
43      /**
44       * Obtains an instance of NdcPatternConverter.
45       *
46       * @param options options, may be null.
47       * @return instance of NdcPatternConverter.
48       */
49      public static NdcPatternConverter newInstance(final String[] options) {
50          return INSTANCE;
51      }
52  
53      @Override
54      @PerformanceSensitive("allocation")
55      public void format(final LogEvent event, final StringBuilder toAppendTo) {
56          toAppendTo.append(event.getContextStack());
57      }
58  }