Test java's dynamic proxy class - to avoid boilplate wrapper code for all classes

ProxyTest.java

package baiyanhuang;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Arrays;
import java.util.Random;

/**
 * Learn Java's dynamic proxy (in reflection)
 * It mainly use the reflection classes: InvocationHandler; Method; Proxy
 */
public class ProxyTest {
    public static void main(String[] args) {
        Object[] elements = new Object[1000];

        // fill elements with proxies for the integers 1 ... 1000
        for (int i = 0; i < elements.length; i++) {
            Integer value = i + 1;

            Class[] interfaces = value.getClass().getInterfaces();
            InvocationHandler handler = new TraceHandler(value);

            // Generate a proxy class on the fly that implement the "interfaces" using "handler", while the "handler"
            // is actually calling the real object's method, adding some extra functionalities, say, logging.
            Object proxy = Proxy.newProxyInstance(null, interfaces, handler);
            elements[i] = proxy;
        }

        // construct a random integer
        Integer key = new Random().nextInt(elements.length) + 1;
        // search for the key
        int result = Arrays.binarySearch(elements, key);
        // print match if found
        if (result >= 0)
            System.out.println(elements[result]);
    }
}

/**
 * An invocation handler that prints out the method name and parameters, then invokes the original method
 */
class TraceHandler implements InvocationHandler {
    public TraceHandler(Object t) {
        target = t;
    }

    // This function is called by the dynamically generated proxy class
    public Object invoke(Object proxy, Method m, Object[] args) throws Throwable {
        // print implicit argument
        System.out.print(target);
        // print method name
        System.out.print("." + m.getName() + "(");
        // print explicit arguments
        if (args != null) {
            for (int i = 0; i < args.length; i++) {
                System.out.print(args[i]);
                if (i < args.length - 1)
                    System.out.print(", ");
            }
        }
        System.out.println(")");
        // invoke actual method
        // return new Integer("123");
        return m.invoke(target, args);
    }

    private Object target;
}