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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.lookup;
18  
19  import java.text.DateFormat;
20  import java.text.SimpleDateFormat;
21  import java.util.Date;
22  
23  import org.apache.logging.log4j.Logger;
24  import org.apache.logging.log4j.core.LogEvent;
25  import org.apache.logging.log4j.core.config.plugins.Plugin;
26  import org.apache.logging.log4j.status.StatusLogger;
27  
28  /**
29   * Formats the current date or the date in the LogEvent. The "key" is used as the format String.
30   */
31  @Plugin(name = "date", category = "Lookup")
32  public class DateLookup implements StrLookup {
33  
34      private static final Logger LOGGER = StatusLogger.getLogger();
35      /**
36       * Looks up the value of the environment variable.
37       * @param key the format to use. If null, the default DateFormat will be used.
38       * @return The value of the environment variable.
39       */
40      @Override
41      public String lookup(final String key) {
42          return formatDate(System.currentTimeMillis(), key);
43      }
44  
45      /**
46       * Looks up the value of the environment variable.
47       * @param event The current LogEvent (is ignored by this StrLookup).
48       * @param key the format to use. If null, the default DateFormat will be used.
49       * @return The value of the environment variable.
50       */
51      @Override
52      public String lookup(final LogEvent event, final String key) {
53          return formatDate(event.getMillis(), key);
54      }
55  
56      private String formatDate(final long date, final String format) {
57          DateFormat dateFormat = null;
58          if (format != null) {
59              try {
60                  dateFormat = new SimpleDateFormat(format);
61              } catch (final Exception ex) {
62                  LOGGER.error("Invalid date format: \"" + format + "\", using default", ex);
63              }
64          }
65          if (dateFormat == null) {
66              dateFormat = DateFormat.getInstance();
67          }
68          return dateFormat.format(new Date(date));
69      }
70  }