How to create a proxy interface in Java?

Question

How to create a proxy for an interface without creating a class that implements it?

I have a specific example: I have an interface, Contact, and you need to create a proxy object that acts like a Contact. This proxy object will be used to run some TestNG tests.

I tried using the JDK approach, but could only find examples that needed the actual implementation of this interface.

I also found that jasssist can help me with this problem and tried to implement a simple example that seems to work until I get an Out of Memory error. Here is a snippet of what I'm doing:

import javassist.util.proxy.MethodFilter;
import javassist.util.proxy.MethodHandler;
import javassist.util.proxy.ProxyFactory

protected final T createMock(final Class<T> clazz) {
    final ProxyFactory factory = new ProxyFactory();
    factory.setInterfaces(new Class[] { clazz });
    factory.setFilter(new MethodFilter() {
        public final boolean isHandled(final Method m) {
            // ignore finalize()
            return !m.getName().equals("finalize");
        }
    });

    final MethodHandler handler = createDefaultMethodHandler();
    try {
        return (T) factory.create(new Class<?>[0], new Object[0], handler);
    } catch (final Exception e) {
        e.printStackTrace();
    }
    return null;
}
private MethodHandler createDefaultMethodHandler() {
    return new MethodHandler() {
        public final Object invoke(final Object self,
                final Method thisMethod, final Method proceed,
                final Object[] args) throws Throwable {
            System.out.println("Handling " + thisMethod
                    + " via the method handler");
            return thisMethod.invoke(self, args);
        }
    };
}

Remember that the createMock () method parameter will be an interface.

thank

Answer 1

newProxyInstance java.lang.reflect.Proxy. :

    Proxy.newProxyInstance(iClazz.getClassLoader(),
        new Class[]{iClazz},
        new YourInvocationHandler())

iClazz - , YourInvocationHandler - java.lang.reflect.InvocationHandler

Answer 2

commons-proxy .

, , - - invoker ( ). , :

ProxyFactory factory = new JavassistProxyFactory();
Object result = 
      factory.createInvokerProxy(invoker, new Class[] {YourInterface.class});

invoker invoker, invoke . ( 4 "invoke" )

, commons-proxy - javassist.

---

, , - . mockito , :

YourInterface yourMock = mock(YourInterface.class);
when(yourMock.someMethod()).thenReturn(yourPreferredResult);

Answer 3

, .

EasyMock (http://easymock.org/) JMock (http://www.jmock.org/) .

- , java.lang.reflect.Proxy.

Answer 4

Exampledepot - java.lang.reflect.proxy http://exampledepot.8waytrips.com/egs/java.lang.reflect/ProxyClass.html

invoke(Object proxy, Method m, Object[] args) .

---

: , , , - , . . Javassist, snippet.

Answer 5

//              return thisMethod.invoke(self, args);
            return null;

Handling public abstract void org.rege.instruments.IPerson.setName(java.lang.String) via the method handler

, ? , OutOfMemory .

Answer 6

, , - ( ). , :

---

Spring invoker proxy ?

Spring ProxyFactoryBean .