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.refresh;
  
  import alluxio.util.CommonUtils;
  
  import com.google.common.base.Preconditions;
  
  import javax.annotation.concurrent.NotThreadSafe;
  
  /**
   * A refresh policy which allows refreshing after a specified timeout is reached.
   */
  @NotThreadSafe
  public class TimeoutRefresh implements RefreshPolicy {
  
    private final long mRefreshPeriodMs;
    private long mLastAttempTimeMs = 0;
    private boolean mFirstAttempt = true;
  
    /**
     * Constructs a refresh facility which allows refreshing after a specified timeout is reached.
     *
     * @param refreshPeriodMs period of time to refresh after, in milliseconds
     */
    public TimeoutRefresh(long refreshPeriodMs) {
      Preconditions.checkArgument(refreshPeriodMs > 0, "Retry timeout must be a positive number");
      mRefreshPeriodMs = refreshPeriodMs;
    }
  
    @Override
    public boolean attempt() {
      if (mFirstAttempt || (CommonUtils.getCurrentMs() - mLastAttempTimeMs) > mRefreshPeriodMs) {
        mLastAttempTimeMs = CommonUtils.getCurrentMs();
        mFirstAttempt = false;
        return true;
      }
      return false;
    }
  }
  