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