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.slf4j.Logger;
  import org.slf4j.helpers.NOPLogger;
  
  import java.util.Objects;
  
  /**
   * Fixed interval supplier.
   */
  public class FixedIntervalSupplier implements SleepIntervalSupplier {
  
    private final long mInterval;
    protected final Logger mLogger;
  
    /**
     * Constructs a new {@link FixedIntervalSupplier}.
     *
     * @param fixedInterval the fixed interval
     * @param logger the logger
     */
    public FixedIntervalSupplier(long fixedInterval, Logger logger) {
      mInterval = fixedInterval;
      mLogger = logger;
    }
  
    /**
     * Constructs a new {@link FixedIntervalSupplier}.
     *
     * @param fixedInterval the fixed interval
     */
    public FixedIntervalSupplier(long fixedInterval) {
      this(fixedInterval, NOPLogger.NOP_LOGGER);
    }
  
    @Override
    public long getNextInterval(long previousTickedMs, long nowTimeStampMillis) {
      if (previousTickedMs == -1) {
        return -1;
      }
      long executionTimeMs = nowTimeStampMillis - previousTickedMs;
      if (executionTimeMs > mInterval) {
        mLogger.warn("{} last execution took {} ms. Longer than the interval {}",
            Thread.currentThread().getName(), executionTimeMs, mInterval);
        return 0;
      }
      return mInterval - executionTimeMs;
    }
  
    @Override
    public long getRunLimit(long previousTickedMs) {
      return mInterval;
    }
  
    @Override
    public boolean equals(Object o) {
      if (this == o) {
        return true;
      }
      if (o == null || getClass() != o.getClass()) {
        return false;
      }
      FixedIntervalSupplier that = (FixedIntervalSupplier) o;
      return mInterval == that.mInterval;
    }
  
    @Override
    public int hashCode() {
      return Objects.hash(mInterval);
    }
  }
  