content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.heartbeat;
  
  import org.junit.rules.TestRule;
  import org.junit.runner.Description;
  import org.junit.runners.model.Statement;
  
  import java.util.Arrays;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * A rule which will temporarily change a heartbeat to being manually scheduled. See
   * {@link HeartbeatScheduler}.
   */
  public final class ManuallyScheduleHeartbeat implements TestRule {
  
    private final List<String> mThreads;
  
    /**
     * @param threads names of the threads to manually schedule; names are defined in
     *        {@link HeartbeatContext}
     */
    public ManuallyScheduleHeartbeat(List<String> threads) {
      mThreads = threads;
    }
  
    /**
     * @param threads names of the threads to manually schedule; names are defined in
     *        {@link HeartbeatContext}
     */
    public ManuallyScheduleHeartbeat(String... threads) {
      this(Arrays.asList(threads));
    }
  
    /**
     * Stores executor threads and corresponding timer class.
     */
    public static class Resource implements AutoCloseable {
      private final List<String> mThreads;
      private final Map<String, Class<? extends HeartbeatTimer>> mPrevious;
  
      public Resource(List<String> threads) {
        mThreads = threads;
        mPrevious = new HashMap<>();
        for (String threadName : mThreads) {
          try {
            mPrevious.put(threadName, HeartbeatContext.getTimerClass(threadName));
            HeartbeatContext.setTimerClass(threadName, HeartbeatContext.SCHEDULED_TIMER_CLASS);
          } catch (Exception e) {
            throw new RuntimeException(e);
          }
        }
      }
  
      @Override
      public void close() throws Exception {
        for (String threadName : mThreads) {
          HeartbeatContext.setTimerClass(threadName, mPrevious.get(threadName));
        }
      }
    }
  
    @Override
    public Statement apply(final Statement statement, Description description) {
      return new Statement() {
        @Override
        public void evaluate() throws Throwable {
          try (Resource resource = new Resource(mThreads)) {
            statement.evaluate();
          }
        }
      };
    }
  }
  