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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.message.MapMessage;
22  import org.apache.logging.log4j.util.IndexedReadOnlyStringMap;
23  
24  /**
25   * Able to handle the contents of the LogEvent's MapMessage and either
26   * output the entire contents of the properties in a similar format to the
27   * java.util.Hashtable.toString(), or to output the value of a specific key
28   * within the Map.
29   */
30  @Plugin(name = "MapPatternConverter", category = PatternConverter.CATEGORY)
31  @ConverterKeys({ "K", "map", "MAP" })
32  public final class MapPatternConverter extends LogEventPatternConverter {
33      /**
34       * Name of property to output.
35       */
36      private final String key;
37  
38      /**
39       * Private constructor.
40       *
41       * @param options options, may be null.
42       */
43      private MapPatternConverter(final String[] options) {
44          super(options != null && options.length > 0 ? "MAP{" + options[0] + '}' : "MAP", "map");
45          key = options != null && options.length > 0 ? options[0] : null;
46      }
47  
48      /**
49       * Obtains an instance of PropertiesPatternConverter.
50       *
51       * @param options options, may be null or first element contains name of property to format.
52       * @return instance of PropertiesPatternConverter.
53       */
54      public static MapPatternConverter newInstance(final String[] options) {
55          return new MapPatternConverter(options);
56      }
57  
58      /**
59       * {@inheritDoc}
60       */
61      @Override
62      public void format(final LogEvent event, final StringBuilder toAppendTo) {
63          MapMessage msg;
64          if (event.getMessage() instanceof MapMessage) {
65              msg = (MapMessage) event.getMessage();
66          } else {
67              return;
68          }
69          final IndexedReadOnlyStringMap sortedMap = msg.getIndexedReadOnlyStringMap();
70          // if there is no additional options, we output every single
71          // Key/Value pair for the Map in a similar format to Hashtable.toString()
72          if (key == null) {
73              if (sortedMap.isEmpty()) {
74                  toAppendTo.append("{}");
75                  return;
76              }
77              toAppendTo.append("{");
78              for (int i = 0; i < sortedMap.size(); i++) {
79                  if (i > 0) {
80                      toAppendTo.append(", ");
81                  }
82                  toAppendTo.append(sortedMap.getKeyAt(i)).append('=').append(sortedMap.getValueAt(i));
83              }
84              toAppendTo.append('}');
85          } else {
86              // otherwise they just want a single key output
87              final String val = sortedMap.getValue(key);
88  
89              if (val != null) {
90                  toAppendTo.append(val);
91              }
92          }
93      }
94  }