/**
    * 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.common.annotations.VisibleForTesting;
  import com.google.common.collect.ImmutableMap;
  
  import java.net.SocketAddress;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.client.MetricsConnection;
  import org.apache.hadoop.hbase.util.ReflectionUtils;
  
  /**
   * Factory to create a {@link org.apache.hadoop.hbase.ipc.RpcClient}
   */
  @InterfaceAudience.Private
  public final class RpcClientFactory {
  
    public static final String CUSTOM_RPC_CLIENT_IMPL_CONF_KEY = "hbase.rpc.client.impl";
  
    private static final ImmutableMap<String, String> DEPRECATED_NAME_MAPPING = ImmutableMap.of(
      "org.apache.hadoop.hbase.ipc.RpcClientImpl", BlockingRpcClient.class.getName(),
      "org.apache.hadoop.hbase.ipc.AsyncRpcClient", NettyRpcClient.class.getName());
  
    /**
     * Private Constructor
     */
    private RpcClientFactory() {
    }
  
    /** Helper method for tests only. Creates an {@code RpcClient} without metrics. */
    @VisibleForTesting
    public static RpcClient createClient(Configuration conf, String clusterId) {
      return createClient(conf, clusterId, null);
    }
  
    /**
     * Creates a new RpcClient by the class defined in the configuration or falls back to
     * RpcClientImpl
     * @param conf configuration
     * @param clusterId the cluster id
     * @param metrics the connection metrics
     * @return newly created RpcClient
     */
    public static RpcClient createClient(Configuration conf, String clusterId,
        MetricsConnection metrics) {
      return createClient(conf, clusterId, null, metrics);
    }
  
    private static String getRpcClientClass(Configuration conf) {
      String rpcClientClass = conf.get(CUSTOM_RPC_CLIENT_IMPL_CONF_KEY);
      if (rpcClientClass == null) {
        return BlockingRpcClient.class.getName();
      }
      String mappedName = DEPRECATED_NAME_MAPPING.get(rpcClientClass);
      return mappedName == null ? rpcClientClass : mappedName;
    }
  
    /**
     * Creates a new RpcClient by the class defined in the configuration or falls back to
     * RpcClientImpl
     * @param conf configuration
     * @param clusterId the cluster id
     * @param localAddr client socket bind address.
     * @param metrics the connection metrics
     * @return newly created RpcClient
     */
    public static RpcClient createClient(Configuration conf, String clusterId,
        SocketAddress localAddr, MetricsConnection metrics) {
      String rpcClientClass = getRpcClientClass(conf);
      return ReflectionUtils.instantiateWithCustomCtor(rpcClientClass, new Class[] {
          Configuration.class, String.class, SocketAddress.class, MetricsConnection.class },
        new Object[] { conf, clusterId, localAddr, metrics });
    }
  }