Client.java 文件源码

/**
 * Take an IOException and the address we were trying to connect to
 * and return an IOException with the input exception as the cause.
 * The new exception provides the stack trace of the place where 
 * the exception is thrown and some extra diagnostics information.
 * If the exception is ConnectException or SocketTimeoutException, 
 * return a new one of the same type; Otherwise return an IOException.
 * 
 * @param addr target address
 * @param exception the relevant exception
 * @return an exception to throw
 */
private IOException wrapException(InetSocketAddress addr,
                                       IOException exception) {
  if (exception instanceof ConnectException) {
    //connection refused; include the host:port in the error
    return (ConnectException)new ConnectException(
         "Call to " + addr + " failed on connection exception: " + exception)
                  .initCause(exception);
  } else if (exception instanceof SocketTimeoutException) {
    return (SocketTimeoutException)new SocketTimeoutException(
         "Call to " + addr + " failed on socket timeout exception: "
                    + exception).initCause(exception);
  } else if (exception instanceof NoRouteToHostException) {
    return (NoRouteToHostException)new NoRouteToHostException(
         "Call to " + addr + " failed on NoRouteToHostException exception: "
                    + exception).initCause(exception);
  } else if (exception instanceof PortUnreachableException) {
    return (PortUnreachableException)new PortUnreachableException(
         "Call to " + addr + " failed on PortUnreachableException exception: "
                    + exception).initCause(exception);
  } else {
    return (IOException)new IOException(
         "Call to " + addr + " failed on local exception: " + exception)
                               .initCause(exception);

  }
}