java.lang.reflect

Class Proxy

java.lang.Object

java.lang.reflect.Proxy

All Implemented Interfaces:

Serializable

public class Proxy
extends Object
implements Serializable

Proxy defines methods for creating dynamic proxy classes and instances. A proxy class implements a declared set of interfaces and delegates method invocations to an InvocationHandler.

Since:

1.3

See Also:

InvocationHandler, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected InvocationHandler	h The invocation handler on which the method calls are dispatched.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Proxy(InvocationHandler h) Constructs a new Proxy instance with the specified invocation handler.

Method Summary

Modifier and Type	Method and Description
static InvocationHandler	getInvocationHandler(Object proxy) Returns the invocation handler of the specified proxy instance.
static Class<?>	getProxyClass(ClassLoader loader, Class<?>... interfaces) Returns the dynamically built Class for the specified interfaces.
static boolean	isProxyClass(Class<?> cl) Indicates whether or not the specified class is a dynamically generated proxy class.
static Object	newProxyInstance(ClassLoader loader, Class<?>[] interfaces, InvocationHandler invocationHandler) Returns an instance of the dynamically built class for the specified interfaces.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

h

protected InvocationHandler h

The invocation handler on which the method calls are dispatched.

Constructor Detail

Proxy

protected Proxy(InvocationHandler h)

Constructs a new Proxy instance with the specified invocation handler.

Parameters:

h - the invocation handler for the newly created proxy

Method Detail

getProxyClass

public static Class<?> getProxyClass(ClassLoader loader,
                                     Class<?>... interfaces)
                              throws IllegalArgumentException

Returns the dynamically built Class for the specified interfaces. Creates a new Class when necessary. The order of the interfaces is relevant. Invocations of this method with the same interfaces but different order result in different generated classes. The interfaces must be visible from the supplied class loader; no duplicates are permitted. All non-public interfaces must be defined in the same package.

Parameters:

loader - the class loader that will define the proxy class

interfaces - an array of Class objects, each one identifying an interface that will be implemented by the returned proxy class

Returns:

a proxy class that implements all of the interfaces referred to in the contents of interfaces

Throws:

IllegalArgumentException - if any of the interface restrictions are violated

NullPointerException - if either interfaces or any of its elements are null

newProxyInstance

public static Object newProxyInstance(ClassLoader loader,
                                      Class<?>[] interfaces,
                                      InvocationHandler invocationHandler)
                               throws IllegalArgumentException

Returns an instance of the dynamically built class for the specified interfaces. Method invocations on the returned instance are forwarded to the specified invocation handler. The interfaces must be visible from the supplied class loader; no duplicates are permitted. All non-public interfaces must be defined in the same package.

Parameters:

loader - the class loader that will define the proxy class

interfaces - an array of Class objects, each one identifying an interface that will be implemented by the returned proxy object

invocationHandler - the invocation handler that handles the dispatched method invocations

Returns:

a new proxy object that delegates to the handler h

Throws:

IllegalArgumentException - if any of the interface restrictions are violated

NullPointerException - if the interfaces or any of its elements are null

isProxyClass

public static boolean isProxyClass(Class<?> cl)

Indicates whether or not the specified class is a dynamically generated proxy class.

Parameters:

cl - the class

Returns:

true if the class is a proxy class, false otherwise

Throws:

NullPointerException - if the class is null

getInvocationHandler

public static InvocationHandler getInvocationHandler(Object proxy)
                                              throws IllegalArgumentException

Returns the invocation handler of the specified proxy instance.

Parameters:

proxy - the proxy instance

Returns:

the invocation handler of the specified proxy instance

Throws:

IllegalArgumentException - if the supplied proxy is not a proxy object