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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 }