# 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` has an instance of this class as that proxy's invocation handler.

Since:
  1.5
See Also:
  - Serialized Form

## Field Summary

### Fields declared in class RemoteObject

`ref`

## Constructor Summary

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

## Method Summary

Modifier and Type
Method
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 declared in class RemoteObject

`equals, getRef, hashCode, toString, toStub`

### Methods declared in class Object

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

## Constructor Details

### 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 Details

### 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.

If `method` overrides `Object.finalize`, it is ignored.

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`