com.google.common.reflect

Class AbstractInvocationHandler

java.lang.Object

com.google.common.reflect.AbstractInvocationHandler

All Implemented Interfaces:

InvocationHandler

@Beta
public abstract class AbstractInvocationHandler
extends Object
implements InvocationHandler

Abstract implementation of InvocationHandler that handles Object.equals(java.lang.Object), Object.hashCode() and Object.toString(). For example:

 class Unsupported extends AbstractInvocationHandler {
   protected Object handleInvocation(Object proxy, Method method, Object[] args) {
     throw new UnsupportedOperationException();
   }
 }

 CharSequence unsupported = Reflection.newProxy(CharSequence.class, new Unsupported());
 

Since:

12.0

Author:

Ben Yu

Constructor Summary

Constructors

Constructor and Description
AbstractInvocationHandler()

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj) By default delegates to Object.equals(java.lang.Object) so instances are only equal if they are identical.
protected abstract Object	handleInvocation(Object proxy, Method method, Object[] args) invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[]) delegates to this method upon any method invocation on the proxy instance, except Object.equals(java.lang.Object), Object.hashCode() and Object.toString().
int	hashCode() By default delegates to Object.hashCode().
Object	invoke(Object proxy, Method method, Object[] args) proxy.hashCode() delegates to hashCode() proxy.toString() delegates to toString() proxy.equals(argument) returns true if: proxy and argument are of the same type and equals(java.lang.Object) returns true for the InvocationHandler of argument other method calls are dispatched to handleInvocation(java.lang.Object, java.lang.reflect.Method, java.lang.Object[]).
String	toString() By default delegates to Object.toString().

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractInvocationHandler

public AbstractInvocationHandler()

Method Detail

invoke

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

• proxy.hashCode() delegates to hashCode()
• proxy.toString() delegates to toString()
• proxy.equals(argument) returns true if:
  • proxy and argument are of the same type
  • and equals(java.lang.Object) returns true for the InvocationHandler of argument
• other method calls are dispatched to handleInvocation(java.lang.Object, java.lang.reflect.Method, java.lang.Object[]).

Specified by:

invoke in interface InvocationHandler

Throws:

Throwable

handleInvocation

protected abstract Object handleInvocation(Object proxy,
                                           Method method,
                                           Object[] args)
                                    throws Throwable

invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[]) delegates to this method upon any method invocation on the proxy instance, except Object.equals(java.lang.Object), Object.hashCode() and Object.toString(). The result will be returned as the proxied method's return value.

Unlike invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[]), args will never be null. When the method has no parameter, an empty array is passed in.

Throws:

Throwable

equals

public boolean equals(Object obj)

By default delegates to Object.equals(java.lang.Object) so instances are only equal if they are identical. proxy.equals(argument) returns true if:

• proxy and argument are of the same type
• and this method returns true for the InvocationHandler of argument

Subclasses can override this method to provide custom equality.

Overrides:

equals in class Object

hashCode

public int hashCode()

By default delegates to Object.hashCode(). The dynamic proxies' hashCode() will delegate to this method. Subclasses can override this method to provide custom equality.

Overrides:

hashCode in class Object

toString

public String toString()

By default delegates to Object.toString(). The dynamic proxies' toString() will delegate to this method. Subclasses can override this method to provide custom string representation for the proxies.

Overrides:

toString in class Object