import org.apache.hadoop.ipc.RPC.RpcInvoker; //导入依赖的package包/类
/**
 * Register a RPC kind and the class to deserialize the rpc request.
 * 
 * Called by static initializers of rpcKind Engines
 * @param rpcKind
 * @param rpcRequestWrapperClass - this class is used to deserialze the
 *  the rpc request.
 *  @param rpcInvoker - use to process the calls on SS.
 */

public static void registerProtocolEngine(RPC.RpcKind rpcKind, 
        Class<? extends Writable> rpcRequestWrapperClass,
        RpcInvoker rpcInvoker) {
  RpcKindMapValue  old = 
      rpcKindMap.put(rpcKind, new RpcKindMapValue(rpcRequestWrapperClass, rpcInvoker));
  if (old != null) {
    rpcKindMap.put(rpcKind, old);
    throw new IllegalArgumentException("ReRegistration of rpcKind: " +
        rpcKind);      
  }
  if (LOG.isDebugEnabled()) {
    LOG.debug("rpcKind=" + rpcKind +
        ", rpcRequestWrapperClass=" + rpcRequestWrapperClass +
        ", rpcInvoker=" + rpcInvoker);
  }
}
 

import org.apache.hadoop.ipc.RPC.RpcInvoker; //导入依赖的package包/类
/**
 * Register a RPC kind and the class to deserialize the rpc request.
 * 
 * Called by static initializers of rpcKind Engines
 * @param rpcKind
 * @param rpcRequestWrapperClass - this class is used to deserialze the
 *  the rpc request.
 *  @param rpcInvoker - use to process the calls on SS.
 */

public static void registerProtocolEngine(RPC.RpcKind rpcKind, 
        Class<? extends Writable> rpcRequestWrapperClass,
        RpcInvoker rpcInvoker) {
  RpcKindMapValue  old = 
      rpcKindMap.put(rpcKind, new RpcKindMapValue(rpcRequestWrapperClass, rpcInvoker));
  if (old != null) {
    rpcKindMap.put(rpcKind, old);
    throw new IllegalArgumentException("ReRegistration of rpcKind: " +
        rpcKind);      
  }
  LOG.debug("rpcKind=" + rpcKind + 
      ", rpcRequestWrapperClass=" + rpcRequestWrapperClass + 
      ", rpcInvoker=" + rpcInvoker);
}
 

import org.apache.hadoop.ipc.RPC.RpcInvoker; //导入依赖的package包/类
RpcKindMapValue (Class<? extends Writable> rpcRequestWrapperClass,
      RpcInvoker rpcInvoker) {
  this.rpcInvoker = rpcInvoker;
  this.rpcRequestWrapperClass = rpcRequestWrapperClass;
}
 

import org.apache.hadoop.ipc.RPC.RpcInvoker; //导入依赖的package包/类
public static RpcInvoker  getRpcInvoker(RPC.RpcKind rpcKind) {
  RpcKindMapValue val = rpcKindMap.get(rpcKind);
  return (val == null) ? null : val.rpcInvoker; 
}