/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hdfs;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.server.namenode.LeaseManager;
import org.junit.Test;

import java.util.ConcurrentModificationException;

import static org.junit.Assert.assertFalse;

/**
 * Test empty file creation.
 */
public class TestFileCreationEmpty {
  private boolean isConcurrentModificationException = false;

  /**
   * This test creates three empty files and lets their leases expire.
   * This triggers release of the leases.
   * The empty files are supposed to be closed by that
   * without causing ConcurrentModificationException.
   */
  @Test
  public void testLeaseExpireEmptyFiles() throws Exception {
    final Thread.UncaughtExceptionHandler oldUEH =
        Thread.getDefaultUncaughtExceptionHandler();
    Thread.setDefaultUncaughtExceptionHandler(
        new Thread.UncaughtExceptionHandler() {
          @Override
          public void uncaughtException(Thread t, Throwable e) {
            if (e instanceof ConcurrentModificationException) {
              LeaseManager.LOG.error("t=" + t, e);
              isConcurrentModificationException = true;
            }
          }
        });

    System.out.println("testLeaseExpireEmptyFiles start");
    final long leasePeriod = 1000;
    final int DATANODE_NUM = 3;

    final Configuration conf = new HdfsConfiguration();
    conf.setInt(DFSConfigKeys.DFS_NAMENODE_HEARTBEAT_RECHECK_INTERVAL_KEY,
        1000);
    conf.setInt(DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_KEY, 1);

    // create cluster
    MiniDFSCluster cluster =
        new MiniDFSCluster.Builder(conf).numDataNodes(DATANODE_NUM).build();
    try {
      cluster.waitActive();
      DistributedFileSystem dfs =
          (DistributedFileSystem) cluster.getFileSystem();

      // create a new file.
      TestFileCreation.createFile(dfs, new Path("/foo"), DATANODE_NUM);
      TestFileCreation.createFile(dfs, new Path("/foo2"), DATANODE_NUM);
      TestFileCreation.createFile(dfs, new Path("/foo3"), DATANODE_NUM);

      // set the soft and hard limit to be 1 second so that the
      // namenode triggers lease recovery
      cluster.setLeasePeriod(leasePeriod, leasePeriod);
      // wait for the lease to expire
      try {
        Thread.sleep(5 * leasePeriod);
      } catch (InterruptedException e) {
      }

      assertFalse(isConcurrentModificationException);
    } finally {
      Thread.setDefaultUncaughtExceptionHandler(oldUEH);
      cluster.shutdown();
    }
  }
}