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;
  
  import com.google.common.base.MoreObjects;
  import com.google.common.base.Preconditions;
  
  import javax.annotation.concurrent.ThreadSafe;
  
  /**
   * Represents one session in the worker daemon.
   */
  @ThreadSafe
  public class SessionInfo {
    private final long mSessionId;
  
    private long mLastHeartbeatMs;
    private final int mSessionTimeoutMs;
  
    /**
     * Creates a new instance of {@link SessionInfo}.
     *
     * @param sessionId the session id
     * @param sessionTimeoutMs the session timeout in milliseconds
     */
    public SessionInfo(long sessionId, int sessionTimeoutMs) {
      Preconditions.checkArgument(sessionId > 0, "Invalid session id " + sessionId);
      Preconditions.checkArgument(sessionTimeoutMs > 0, "Invalid session timeout");
      mSessionId = sessionId;
      mLastHeartbeatMs = System.currentTimeMillis();
      mSessionTimeoutMs = sessionTimeoutMs;
    }
  
    /**
     * @return the session id
     */
    public long getSessionId() {
      return mSessionId;
    }
  
    /**
     * Performs a session heartbeat.
     */
    public synchronized void heartbeat() {
      mLastHeartbeatMs = System.currentTimeMillis();
    }
  
    /**
     * Checks whether the session has timed out.
     *
     * @return true if the session has timed out and false otherwise
     */
    public synchronized boolean timeout() {
      return (System.currentTimeMillis() - mLastHeartbeatMs > mSessionTimeoutMs);
    }
  
    @Override
    public synchronized String toString() {
      return MoreObjects.toStringHelper(this).add("sessionId", mSessionId)
          .add("lastHeartbeatMs", mLastHeartbeatMs).toString();
    }
  
    @Override
    public boolean equals(Object o) {
      if (this == o) {
        return true;
      }
      if (!(o instanceof SessionInfo)) {
        return false;
      }
      SessionInfo that = (SessionInfo) o;
      return mSessionId == that.mSessionId;
    }
  
    @Override
    public int hashCode() {
      return (int) (mSessionId ^ (mSessionId >>> 32));
    }
  }
  