/*
   * Copyright 2011 Alibaba.com All right reserved. This software is the
   * confidential and proprietary information of Alibaba.com ("Confidential
   * Information"). You shall not disclose such Confidential Information and shall
   * use it only in accordance with the terms of the license agreement you entered
   * into with Alibaba.com.
   
 
*/
  package com.alibaba.study.rpc.framework;
  ​
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.lang.reflect.InvocationHandler;
  import java.lang.reflect.Method;
  import java.lang.reflect.Proxy;
  import java.net.ServerSocket;
  import java.net.Socket;
  ​
  
 
/**
   * RpcFramework
   * 
   * @author william.liangf
   */
  public class RpcFramework {
  ​
      /**
       * 暴露服務
       * 
       * @param service 服務實現
       * @param port 服務埠
       * @throws Exception
       */
      public static void export(final Object service, int port) throws Exception {
          
 
if (service == null)
              throw new IllegalArgumentException("service instance == null");
          if (port <= 0 || port > 65535)
              throw new IllegalArgumentException("Invalid port " + port);
          System.out.println("Export service " + service.getClass().getName() + " on port " + port);
          ServerSocket server = new ServerSocket(port);
          for(;;) {
              try {
                  final Socket socket = server.accept();
                  new Thread(new Runnable() {
                      @Override
                      public void run() {
                          try {
                              try {
                                  ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
                                  try {
                                      String methodName = input.readUTF();
                                      Class<?>[] parameterTypes = (Class<?>[])input.readObject();
                                      Object[] arguments = (Object[])input.readObject();
                                      ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
                                      try {
                                          Method method = service.getClass().getMethod(methodName, parameterTypes);
                                          Object result = method.invoke(service, arguments);
                                          output.writeObject(result);
                                      } catch (Throwable t) {
                                          output.writeObject(t);
                                      } finally {
                                          output.close();
                                      }
                                  } finally {
                                      input.close();
                                  }
                              } finally {
                                  socket.close();
                              }
                          } catch (Exception e) {
                              e.printStackTrace();
                          }
                      }
                  }).start();
              } catch (Exception e) {
                  e.printStackTrace();
              }
          }
      }
  ​
      /**
       * 引用服務
       * 
       * @param <T> 介面泛型
       * @param interfaceClass 介面型別
       * @param host 伺服器主機名
       * @param port 伺服器埠
       * @return 遠端服務
       * @throws Exception
       */
      @SuppressWarnings("unchecked")
      public static <T> T refer(final Class<T> interfaceClass, final String host, final int port) throws Exception {
          if (interfaceClass == null)
              throw new IllegalArgumentException("Interface class == null");
          if (! interfaceClass.isInterface())
              throw new IllegalArgumentException("The " + interfaceClass.getName() + " must be interface class!");
          if (host == null || host.length() == 0)
              throw new IllegalArgumentException("Host == null!");
          if (port <= 0 || port > 65535)
              throw new IllegalArgumentException("Invalid port " + port);
          System.out.println("Get remote service " + interfaceClass.getName() + " from server " + host + ":" + port);
          return (T) Proxy.newProxyInstance(interfaceClass.getClassLoader(), new Class<?>[] {interfaceClass}, new InvocationHandler() {
              public Object invoke(Object proxy, Method method, Object[] arguments) throws Throwable {
                  Socket socket = new Socket(host, port);
                  try {
                      ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
                      try {
                          output.writeUTF(method.getName());
                          output.writeObject(method.getParameterTypes());
                          output.writeObject(arguments);
                          ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
                          try {
                              Object result = input.readObject();
                              if (result instanceof Throwable) {
                                  throw (Throwable) result;
                              }
                              return result;
                          } finally {
                              input.close();
                          }
                      } finally {
                          output.close();
                      }
                  } finally {
                      socket.close();  
                }  
            }  
        });  
    }  
​  
}