001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.hadoop.ha;
019    
020    import java.io.IOException;
021    
022    import org.apache.hadoop.classification.InterfaceAudience;
023    import org.apache.hadoop.classification.InterfaceStability;
024    import org.apache.hadoop.ha.HAServiceProtocol.StateChangeRequestInfo;
025    import org.apache.hadoop.ipc.RemoteException;
026    
027    /**
028     * Helper for making {@link HAServiceProtocol} RPC calls. This helper
029     * unwraps the {@link RemoteException} to specific exceptions.
030     */
031    @InterfaceAudience.Public
032    @InterfaceStability.Evolving
033    public class HAServiceProtocolHelper {
034      public static void monitorHealth(HAServiceProtocol svc,
035          StateChangeRequestInfo reqInfo)
036          throws IOException {
037        try {
038          svc.monitorHealth();
039        } catch (RemoteException e) {
040          throw e.unwrapRemoteException(HealthCheckFailedException.class);
041        }
042      }
043    
044      public static void transitionToActive(HAServiceProtocol svc,
045          StateChangeRequestInfo reqInfo)
046          throws IOException {
047        try {
048          svc.transitionToActive(reqInfo);
049        } catch (RemoteException e) {
050          throw e.unwrapRemoteException(ServiceFailedException.class);
051        }
052      }
053    
054      public static void transitionToStandby(HAServiceProtocol svc,
055          StateChangeRequestInfo reqInfo)
056          throws IOException {
057        try {
058          svc.transitionToStandby(reqInfo);
059        } catch (RemoteException e) {
060          throw e.unwrapRemoteException(ServiceFailedException.class);
061        }
062      }
063    }