RetryNTimes.java

/*
 * Copyright © 2012-2014 Cask Data, Inc.
 *
 * Licensed 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 co.cask.tephra.distributed;

import co.cask.tephra.TxConstants;
import org.apache.hadoop.conf.Configuration;

/**
 * A retry strategy that makes N attempts and then gives up. This does
 * not do anything before the re-attempt - extend this class to add a
 * sleep or similar.
 */
public class RetryNTimes extends RetryStrategy {

  int attempts = 0;
  int limit;

  /**
   * @param maxAttempts the number of attempts after which to stop
   */
  protected RetryNTimes(int maxAttempts) {
    limit = maxAttempts;
  }

  @Override
  boolean failOnce() {
    ++attempts;
    return attempts < limit;
  }

  /**
   * A retry strategy provider for this strategy.
   */
  public static class Provider implements RetryStrategyProvider {

    int nTimes;

    public Provider() {
      this.nTimes = TxConstants.Service.DEFAULT_DATA_TX_CLIENT_ATTEMPTS;
    }

    @Override
    public void configure(Configuration config) {
      nTimes = config.getInt(TxConstants.Service.CFG_DATA_TX_CLIENT_ATTEMPTS, nTimes);
    }

    @Override
    public RetryStrategy newRetryStrategy() {
      return new RetryNTimes(nTimes);
    }

    @Override
    public String toString() {
      return nTimes + " attempts without delay";
    }
  }
}