branch-2.0.4-alpha/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ha/HAServiceProtocolHelper.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.ha;

import java.io.IOException;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.ha.HAServiceProtocol.StateChangeRequestInfo;
import org.apache.hadoop.ipc.RemoteException;

/**
 * Helper for making {@link HAServiceProtocol} RPC calls. This helper
 * unwraps the {@link RemoteException} to specific exceptions.
 */
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class HAServiceProtocolHelper {
  public static void monitorHealth(HAServiceProtocol svc,
      StateChangeRequestInfo reqInfo)
      throws IOException {
    try {
      svc.monitorHealth();
    } catch (RemoteException e) {
      throw e.unwrapRemoteException(HealthCheckFailedException.class);
    }
  }

  public static void transitionToActive(HAServiceProtocol svc,
      StateChangeRequestInfo reqInfo)
      throws IOException {
    try {
      svc.transitionToActive(reqInfo);
    } catch (RemoteException e) {
      throw e.unwrapRemoteException(ServiceFailedException.class);
    }
  }

  public static void transitionToStandby(HAServiceProtocol svc,
      StateChangeRequestInfo reqInfo)
      throws IOException {
    try {
      svc.transitionToStandby(reqInfo);
    } catch (RemoteException e) {
      throw e.unwrapRemoteException(ServiceFailedException.class);
    }
  }
}