Class AbstractInvocationHandler

java.lang.Object

com.google.common.reflect.AbstractInvocationHandler

All Implemented Interfaces:

InvocationHandler

public abstract class AbstractInvocationHandler
extends Object
implements InvocationHandler

Abstract implementation of InvocationHandler that handles Object.equals(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	Description
AbstractInvocationHandler()	Constructor for use by subclasses.

Method Summary

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

Methods inherited from class Object

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

Constructor Details

AbstractInvocationHandler

public AbstractInvocationHandler()

Constructor for use by subclasses.

Method Details

invoke

public final @Nullable Object invoke(Object proxy,
 Method method,
 @Nullable Object @Nullable [] 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(Object) returns true for the InvocationHandler of argument
• other method calls are dispatched to handleInvocation(Object, Method, Object[]).

Specified by:

invoke in interface InvocationHandler

Throws:

Throwable

handleInvocation

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

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

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

Throws:

Throwable

equals

public boolean equals(@Nullable Object obj)

By default delegates to Object.equals(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