/*
    * 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.hbase.ipc;
  
  import com.google.protobuf.Descriptors;
  import com.google.protobuf.Message;
  import com.google.protobuf.RpcController;
  
  import java.io.IOException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.client.ClusterConnection;
  import org.apache.hadoop.hbase.client.RegionServerCallable;
  import org.apache.hadoop.hbase.client.RpcRetryingCallerFactory;
  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.CoprocessorServiceResponse;
  import org.apache.hadoop.hbase.util.Bytes;
  
  /**
   * Provides clients with an RPC connection to call coprocessor endpoint {@link com.google.protobuf.Service}s
   * against a given table region.  An instance of this class may be obtained
   * by calling {@link org.apache.hadoop.hbase.client.HTable#coprocessorService(byte[])},
   * but should normally only be used in creating a new {@link com.google.protobuf.Service} stub to call the endpoint
   * methods.
   * @see org.apache.hadoop.hbase.client.HTable#coprocessorService(byte[])
   */
  @InterfaceAudience.Private
  public class RegionCoprocessorRpcChannel extends CoprocessorRpcChannel{
    private static final Log LOG = LogFactory.getLog(RegionCoprocessorRpcChannel.class);
  
    private final ClusterConnection connection;
    private final TableName table;
    private final byte[] row;
    private byte[] lastRegion;
    private int operationTimeout;
  
    private RpcRetryingCallerFactory rpcCallerFactory;
    private RpcControllerFactory rpcControllerFactory;
  
    public RegionCoprocessorRpcChannel(ClusterConnection conn, TableName table, byte[] row) {
      this.connection = conn;
      this.table = table;
      this.row = row;
      this.rpcCallerFactory = conn.getRpcRetryingCallerFactory();
      this.rpcControllerFactory = conn.getRpcControllerFactory();
      this.operationTimeout = conn.getConnectionConfiguration().getOperationTimeout();
    }
  
    @Override
    protected Message callExecService(RpcController controller,
        Descriptors.MethodDescriptor method, Message request, Message responsePrototype)
            throws IOException {
      if (LOG.isTraceEnabled()) {
        LOG.trace("Call: "+method.getName()+", "+request.toString());
      }
  
      if (row == null) {
        throw new IllegalArgumentException("Missing row property for remote region location");
      }
  
      final RpcController rpcController = controller == null
          ? rpcControllerFactory.newController() : controller;
  
      final ClientProtos.CoprocessorServiceCall call =
          CoprocessorRpcUtils.buildServiceCall(row, method, request);
      RegionServerCallable<CoprocessorServiceResponse> callable =
          new RegionServerCallable<CoprocessorServiceResponse>(connection, table, row, HConstants.PRIORITY_UNSET) {
        @Override
        public CoprocessorServiceResponse call(int callTimeout) throws Exception {
          if (rpcController instanceof HBaseRpcController) {
            HBaseRpcController hrc = (HBaseRpcController) rpcController;
            hrc.setPriority(tableName);
            hrc.setCallTimeout(callTimeout);
          }
          byte[] regionName = getLocation().getRegionInfo().getRegionName();
          return ProtobufUtil.execService(rpcController, getStub(), call, regionName);
        }
      };
     CoprocessorServiceResponse result = rpcCallerFactory.<CoprocessorServiceResponse> newCaller()
         .callWithRetries(callable, operationTimeout);
     Message response = null;
     if (result.getValue().hasValue()) {
       Message.Builder builder = responsePrototype.newBuilderForType();
       ProtobufUtil.mergeFrom(builder, result.getValue().getValue());
       response = builder.build();
     } else {
       response = responsePrototype.getDefaultInstanceForType();
     }
     lastRegion = result.getRegion().getValue().toByteArray();
     if (LOG.isTraceEnabled()) {
       LOG.trace("Result is region=" + Bytes.toStringBinary(lastRegion) + ", value=" + response);
     }
     return response;
   }
 
   public byte[] getLastRegion() {
     return lastRegion;
   }
 }