/*
    *
    * 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 java.lang.reflect.InvocationHandler;
  import java.lang.reflect.Method;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.classification.InterfaceAudience;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.client.HConnection;
  import org.apache.hadoop.hbase.client.ServerCallable;
  import org.apache.hadoop.hbase.client.coprocessor.Exec;
  import org.apache.hadoop.hbase.client.coprocessor.ExecResult;
  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
  import org.apache.hadoop.hbase.util.Bytes;
  
  /**
   * Backs a {@link CoprocessorProtocol} subclass proxy and forwards method
   * invocations for server execution.  Note that internally this will issue a
   * separate RPC call for each method invocation (using a
   * {@link org.apache.hadoop.hbase.client.ServerCallable} instance).
   */
  @InterfaceAudience.Private
  @Deprecated
  public class ExecRPCInvoker implements InvocationHandler {
    // LOG is NOT in hbase subpackage intentionally so that the default HBase
    // DEBUG log level does NOT emit RPC-level logging. 
    private static final Log LOG = LogFactory.getLog("org.apache.hadoop.ipc.ExecRPCInvoker");
  
    private Configuration conf;
    private final HConnection connection;
    private Class<? extends CoprocessorProtocol> protocol;
    private final byte[] table;
    private final byte[] row;
    private byte[] regionName;
  
    public ExecRPCInvoker(Configuration conf,
        HConnection connection,
        Class<? extends CoprocessorProtocol> protocol,
        byte[] table,
        byte[] row) {
      this.conf = conf;
      this.connection = connection;
      this.protocol = protocol;
      this.table = table;
      this.row = row;
    }
  
    @Override
    public Object invoke(Object instance, final Method method, final Object[] args)
        throws Throwable {
      if (LOG.isDebugEnabled()) {
        LOG.debug("Call: "+method.getName()+", "+(args != null ? args.length : 0));
      }
  
      if (row != null) {
        final Exec exec = new Exec(conf, row, protocol, method, args);
        ServerCallable<ExecResult> callable =
            new ServerCallable<ExecResult>(connection, table, row) {
              public ExecResult call() throws Exception {
                byte[] regionName = location.getRegionInfo().getRegionName();
                return ProtobufUtil.execCoprocessor(server, exec, regionName);
              }
            };
          ExecResult result = callable.withRetries();
          this.regionName = result.getRegionName();
          LOG.debug("Result is region="+ Bytes.toStringBinary(regionName) +
              ", value="+result.getValue());
          return result.getValue();
      } else if (LOG.isDebugEnabled()) {
        LOG.debug("Null row passed for call");
      }
  
      return null;
    }
  
    public byte[] getRegionName() {
      return regionName;
    }
  }