RemoteObjectInvocationHandler (Java Platform SE 8 )
Keywords: java.rmi.server.RemoteObjectInvocationHandler class
Date: 2017-07-29

compact2, compact3
java.rmi.server

## Class RemoteObjectInvocationHandler

- java.lang.Object
- - java.rmi.server.RemoteObject
  - - java.rmi.server.RemoteObjectInvocationHandler

- All Implemented Interfaces:
    Serializable, InvocationHandler, Remote

      public class RemoteObjectInvocationHandler
      extends RemoteObject
      implements InvocationHandler

  An implementation of the `InvocationHandler` interface for use with Java Remote Method Invocation (Java RMI). This invocation handler can be used in conjunction with a dynamic proxy instance as a replacement for a pregenerated stub class.

  Applications are not expected to use this class directly. A remote object exported to use a dynamic proxy with `UnicastRemoteObject` or `Activatable` has an instance of this class as that proxy's invocation handler.

  Since:
    1.5
  See Also:
    Serialized Form

- - ### Field Summary

    - ### Fields inherited from class java.rmi.server.RemoteObject

      `ref`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `RemoteObjectInvocationHandler(RemoteRef ref)` Creates a new `RemoteObjectInvocationHandler` constructed with the specified `RemoteRef`.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Object` | `invoke(Object proxy, Method method, Object[] args)` Processes a method invocation made on the encapsulating proxy instance, `proxy`, and returns the result.

    - ### Methods inherited from class java.rmi.server.RemoteObject

      `equals, getRef, hashCode, toString, toStub`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### RemoteObjectInvocationHandler

          public RemoteObjectInvocationHandler(RemoteRef ref)

      Creates a new `RemoteObjectInvocationHandler` constructed with the specified `RemoteRef`.
      Parameters:
        `ref` - the remote ref
      Throws:
        `NullPointerException` - if `ref` is `null`

  - ### Method Detail

    - #### invoke

          public Object invoke(Object proxy,
                               Method method,
                               Object[] args)
                        throws Throwable

      Processes a method invocation made on the encapsulating proxy instance, `proxy`, and returns the result.

      `RemoteObjectInvocationHandler` implements this method as follows:

      If `method` is one of the following methods, it is processed as described below:

      - `Object.hashCode`: Returns the hash code value for the proxy.
      - `Object.equals`: Returns `true` if the argument (`args[0]`) is an instance of a dynamic proxy class and this invocation handler is equal to the invocation handler of that argument, and returns `false` otherwise.
      - `Object.toString`: Returns a string representation of the proxy.

      Otherwise, a remote call is made as follows:

      - If `proxy` is not an instance of the interface `Remote`, then an `IllegalArgumentException` is thrown.
      - Otherwise, the `invoke` method is invoked on this invocation handler's `RemoteRef`, passing `proxy`, `method`, `args`, and the method hash (defined in section 8.3 of the "Java Remote Method Invocation (RMI) Specification") for `method`, and the result is returned.
      - If an exception is thrown by `RemoteRef.invoke` and that exception is a checked exception that is not assignable to any exception in the `throws` clause of the method implemented by the `proxy`'s class, then that exception is wrapped in an `UnexpectedException` and the wrapped exception is thrown. Otherwise, the exception thrown by `invoke` is thrown by this method.

      The semantics of this method are unspecified if the arguments could not have been produced by an instance of some valid dynamic proxy class containing this invocation handler.

      Specified by:
        `invoke` in interface `InvocationHandler`
      Parameters:
        `proxy` - the proxy instance that the method was invoked on
        `method` - the `Method` instance corresponding to the interface method invoked on the proxy instance
        `args` - an array of objects containing the values of the arguments passed in the method invocation on the proxy instance, or `null` if the method takes no arguments
      Returns:
        the value to return from the method invocation on the proxy instance
      Throws:
        `Throwable` - the exception to throw from the method invocation on the proxy instance
      See Also:
        `UndeclaredThrowableException`

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