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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.core.util.Loader;
25  import org.apache.logging.log4j.status.StatusLogger;
26  
27  /**
28   * Triggers a rollover on every restart. The target file's timestamp is compared with the JVM start time
29   * and if it is older isTriggeringEvent will return true. After isTriggeringEvent has been called it will
30   * always return false.
31   */
32  @Plugin(name = "OnStartupTriggeringPolicy", category = "Core", printObject = true)
33  public class OnStartupTriggeringPolicy implements TriggeringPolicy {
34      private static long JVM_START_TIME = initStartTime();
35  
36      private boolean evaluated = false;
37      private RollingFileManager manager;
38  
39      /**
40       * Provide the RollingFileManager to the policy.
41       * @param manager The RollingFileManager.
42       */
43      @Override
44      public void initialize(final RollingFileManager manager) {
45          this.manager = manager;
46          if (JVM_START_TIME == 0) {
47              evaluated = true;
48          }
49      }
50  
51      /**
52       * Returns the result of {@code ManagementFactory.getRuntimeMXBean().getStartTime()},
53       * or the current system time if JMX is not available.
54       */
55      private static long initStartTime() {
56          // LOG4J2-379:
57          // We'd like to call ManagementFactory.getRuntimeMXBean().getStartTime(),
58          // but Google App Engine throws a java.lang.NoClassDefFoundError
59          // "java.lang.management.ManagementFactory is a restricted class".
60          // The reflection is necessary because without it, Google App Engine
61          // will refuse to initialize this class.
62          try {
63              final Class<?> factoryClass = Loader.loadSystemClass("java.lang.management.ManagementFactory");
64              final Method getRuntimeMXBean = factoryClass.getMethod("getRuntimeMXBean");
65              final Object runtimeMXBean = getRuntimeMXBean.invoke(null);
66              
67              final Class<?> runtimeMXBeanClass = Loader.loadSystemClass("java.lang.management.RuntimeMXBean");
68              final Method getStartTime = runtimeMXBeanClass.getMethod("getStartTime");
69              final Long result = (Long) getStartTime.invoke(runtimeMXBean);
70  
71              return result.longValue();
72          } catch (final Throwable t) {
73              StatusLogger.getLogger().error("Unable to call ManagementFactory.getRuntimeMXBean().getStartTime(), " //
74                      + "using system time for OnStartupTriggeringPolicy", t);
75              // We have little option but to declare "now" as the beginning of time.
76              return System.currentTimeMillis();
77          }
78      }
79  
80      /**
81       * Determine if a rollover should be triggered.
82       * @param event   A reference to the current event.
83       * @return true if the target file's timestamp is older than the JVM start time.
84       */
85      @Override
86      public boolean isTriggeringEvent(final LogEvent event) {
87          if (evaluated) {
88              return false;
89          }
90          evaluated = true;
91          return manager.getFileTime() < JVM_START_TIME;
92      }
93  
94      @Override
95      public String toString() {
96          return "OnStartupTriggeringPolicy";
97      }
98  
99      @PluginFactory
100     public static OnStartupTriggeringPolicy createPolicy() {
101         return new OnStartupTriggeringPolicy();
102     }
103 }