branch-2.0.4-alpha/hadoop-tools/hadoop-distcp/src/test/java/org/apache/hadoop/tools/util/TestRetriableCommand.java

/**
 * 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.tools.util;

import org.apache.hadoop.io.retry.RetryPolicy;
import org.apache.hadoop.io.retry.RetryPolicies;
import org.junit.Assert;
import org.junit.Test;

import java.util.concurrent.TimeUnit;

public class TestRetriableCommand {

  private static class MyRetriableCommand extends RetriableCommand {

    private int succeedAfter;
    private int retryCount = 0;

    public MyRetriableCommand(int succeedAfter) {
      super("MyRetriableCommand");
      this.succeedAfter = succeedAfter;
    }

    public MyRetriableCommand(int succeedAfter, RetryPolicy retryPolicy) {
      super("MyRetriableCommand", retryPolicy);
      this.succeedAfter = succeedAfter;
    }

    @Override
    protected Object doExecute(Object... arguments) throws Exception {
      if (++retryCount < succeedAfter)
        throw new Exception("Transient failure#" + retryCount);
      return 0;
    }
  }

  @Test
  public void testRetriableCommand() {
    try {
      new MyRetriableCommand(5).execute(0);
      Assert.assertTrue(false);
    }
    catch (Exception e) {
      Assert.assertTrue(true);
    }


    try {
      new MyRetriableCommand(3).execute(0);
      Assert.assertTrue(true);
    }
    catch (Exception e) {
      Assert.assertTrue(false);
    }

    try {
      new MyRetriableCommand(5, RetryPolicies.
          retryUpToMaximumCountWithFixedSleep(5, 0, TimeUnit.MILLISECONDS)).execute(0);
      Assert.assertTrue(true);
    }
    catch (Exception e) {
      Assert.assertTrue(false);
    }
  }
}