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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.appender.rolling;
18  
19  import java.lang.reflect.Method;
20  
21  import org.apache.logging.log4j.core.LogEvent;
22  import org.apache.logging.log4j.core.config.plugins.Plugin;
23  import org.apache.logging.log4j.core.config.plugins.PluginFactory;
24  import org.apache.logging.log4j.status.StatusLogger;
25  
26  /**
27   * Trigger a rollover on every restart. The target file's timestamp is compared with the JVM start time
28   * and if it is older isTriggeringEvent will return true. After isTriggeringEvent has been called it will
29   * always return false.
30   */
31  @Plugin(name = "OnStartupTriggeringPolicy", category = "Core", printObject = true)
32  public class OnStartupTriggeringPolicy implements TriggeringPolicy {
33      private static long JVM_START_TIME = initStartTime();
34  
35      private boolean evaluated = false;
36      private RollingFileManager manager;
37  
38      /**
39       * Provide the RollingFileManager to the policy.
40       * @param manager The RollingFileManager.
41       */
42      @Override
43      public void initialize(final RollingFileManager manager) {
44          this.manager = manager;
45          if (JVM_START_TIME == 0) {
46              evaluated = true;
47          }
48      }
49  
50      /**
51       * Returns the result of {@code ManagementFactory.getRuntimeMXBean().getStartTime()},
52       * or the current system time if JMX is not available.
53       */
54      private static long initStartTime() {
55          // LOG4J2-379:
56          // We'd like to call ManagementFactory.getRuntimeMXBean().getStartTime(),
57          // but Google App Engine throws a java.lang.NoClassDefFoundError
58          // "java.lang.management.ManagementFactory is a restricted class".
59          // The reflection is necessary because without it, Google App Engine
60          // will refuse to initialize this class.
61          try {
62              Class<?> factoryClass = Class.forName("java.lang.management.ManagementFactory");
63              Method getRuntimeMXBean = factoryClass.getMethod("getRuntimeMXBean", new Class[0]);
64              Object runtimeMXBean = getRuntimeMXBean.invoke(null, new Object[0]);
65              
66              Class<?> runtimeMXBeanClass = Class.forName("java.lang.management.RuntimeMXBean");
67              Method getStartTime = runtimeMXBeanClass.getMethod("getStartTime", new Class[0]);
68              Long result = (Long) getStartTime.invoke(runtimeMXBean, new Object[0]);
69              
70              return result.longValue();
71          } catch (Throwable t) {
72              StatusLogger.getLogger().error("Unable to call ManagementFactory.getRuntimeMXBean().getStartTime(), " //
73                      + "using system time for OnStartupTriggeringPolicy", t);
74              // We have little option but to declare "now" as the beginning of time.
75              return System.currentTimeMillis();
76          }
77      }
78  
79      /**
80       * Determine if a rollover should be triggered.
81       * @param event   A reference to the current event.
82       * @return true if the target file's timestamp is older than the JVM start time.
83       */
84      @Override
85      public boolean isTriggeringEvent(final LogEvent event) {
86          if (evaluated) {
87              return false;
88          }
89          evaluated = true;
90          return manager.getFileTime() < JVM_START_TIME;
91      }
92  
93      @Override
94      public String toString() {
95          return "OnStartupTriggeringPolicy";
96      }
97  
98      @PluginFactory
99      public static OnStartupTriggeringPolicy createPolicy() {
100         return new OnStartupTriggeringPolicy();
101     }
102 }