// reflection/SelectingMethods.java

// (c)2021 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

// Looking for particular methods in a dynamic proxy

import java.lang.reflect.*;

class MethodSelector implements InvocationHandler {

private Object proxied;

MethodSelector(Object proxied) {

this.proxied = proxied;

}

@Override public Object

invoke(Object proxy, Method method, Object[] args)

throws Throwable {

if(method.getName().equals("interesting"))

System.out.println(

"Proxy detected the interesting method");

return method.invoke(proxied, args);

}

}

interface SomeMethods {

void boring1();

void boring2();

void interesting(String arg);

void boring3();

}

class Implementation implements SomeMethods {

@Override public void boring1() {

System.out.println("boring1");

}

@Override public void boring2() {

System.out.println("boring2");

}

@Override public void interesting(String arg) {

System.out.println("interesting " + arg);

}

@Override public void boring3() {

System.out.println("boring3");

}

}

class SelectingMethods {

public static void main(String[] args) {

SomeMethods proxy =

(SomeMethods)Proxy.newProxyInstance(

SomeMethods.class.getClassLoader(),

new Class[]{ SomeMethods.class },

new MethodSelector(new Implementation()));

proxy.boring1();

proxy.boring2();

proxy.interesting("bonobo");

proxy.boring3();

}

}

/* Output:

boring1

boring2

Proxy detected the interesting method

interesting bonobo

boring3

*/