Interface InvocationHandler
- All Known Implementing Classes:
-
CompositeDataInvocationHandler
,EventHandler
,MBeanServerInvocationHandler
,RemoteObjectInvocationHandler
public interface InvocationHandler
InvocationHandler
is the interface implemented by the invocation handler of a proxy instance.
Each proxy instance has an associated invocation handler. When a method is invoked on a proxy instance, the method invocation is encoded and dispatched to the invoke
method of its invocation handler.
- Since:
- 1.3
- See Also:
Proxy
Method Summary
Modifier and Type | Method | Description |
---|---|---|
Object | invoke(Object proxy,
Method method,
Object[] args) | Processes a method invocation on a proxy instance and returns the result. |
Method Detail
invoke
Object invoke(Object proxy, Method method, Object[] args) throws Throwable
Processes a method invocation on a proxy instance and returns the result. This method will be invoked on an invocation handler when a method is invoked on a proxy instance that it is associated with.
- Parameters:
-
proxy
- the proxy instance that the method was invoked on -
method
- theMethod
instance corresponding to the interface method invoked on the proxy instance. The declaring class of theMethod
object will be the interface that the method was declared in, which may be a superinterface of the proxy interface that the proxy class inherits the method through. -
args
- an array of objects containing the values of the arguments passed in the method invocation on the proxy instance, ornull
if interface method takes no arguments. Arguments of primitive types are wrapped in instances of the appropriate primitive wrapper class, such asjava.lang.Integer
orjava.lang.Boolean
. - Returns:
- the value to return from the method invocation on the proxy instance. If the declared return type of the interface method is a primitive type, then the value returned by this method must be an instance of the corresponding primitive wrapper class; otherwise, it must be a type assignable to the declared return type. If the value returned by this method is
null
and the interface method's return type is primitive, then aNullPointerException
will be thrown by the method invocation on the proxy instance. If the value returned by this method is otherwise not compatible with the interface method's declared return type as described above, aClassCastException
will be thrown by the method invocation on the proxy instance. - Throws:
-
Throwable
- the exception to throw from the method invocation on the proxy instance. The exception's type must be assignable either to any of the exception types declared in thethrows
clause of the interface method or to the unchecked exception typesjava.lang.RuntimeException
orjava.lang.Error
. If a checked exception is thrown by this method that is not assignable to any of the exception types declared in thethrows
clause of the interface method, then anUndeclaredThrowableException
containing the exception that was thrown by this method will be thrown by the method invocation on the proxy instance. - See Also:
UndeclaredThrowableException