package cutils.reflection;
public class Delegator {
private static java.lang.reflect.Method hashCodeMethod;
private static java.lang.reflect.Method equalsMethod;
private static java.lang.reflect.Method toStringMethod;
static {
try {
hashCodeMethod = Object.class.getMethod("hashCode", null);
equalsMethod =
Object.class.getMethod("equals", new Class[]{Object.class
});
toStringMethod = Object.class.getMethod("toString", null);
} catch (NoSuchMethodException e) {
throw new NoSuchMethodError(e.getMessage());
}
}
private Class[] interfaces;
private Object[] delegates;
public Delegator(Class[] interfaces, Object[] delegates) {
this.interfaces = (Class[]) interfaces.clone();
this.delegates = (Object[]) delegates.clone();
}
public Object invoke(Object proxy, java.lang.reflect.Method m, Object[] args)
throws Throwable {
Class declaringClass = m.getDeclaringClass();
if (declaringClass == Object.class) {
if (m.equals(hashCodeMethod)) {
return proxyHashCode(proxy);
} else if (m.equals(equalsMethod)) {
return proxyEquals(proxy, args[0]);
} else if (m.equals(toStringMethod)) {
return proxyToString(proxy);
} else {
throw new InternalError(
"unexpected Object method dispatched: " + m);
}
} else {
for (int i = 0; i < interfaces.length; i++) {
if (declaringClass.isAssignableFrom(interfaces[i])) {
try {
return m.invoke(delegates[i], args);
} catch (java.lang.reflect.InvocationTargetException e) {
throw e.getTargetException();
}
}
}
return invokeNotDelegated(proxy, m, args);
}
}
protected Object invokeNotDelegated(Object proxy, java.lang.reflect.Method m,
Object[] args)
throws Throwable {
throw new InternalError("unexpected method dispatched: " + m);
}
protected Integer proxyHashCode(Object proxy) {
return new Integer(System.identityHashCode(proxy));
}
protected Boolean proxyEquals(Object proxy, Object other) {
return (proxy == other ? Boolean.TRUE : Boolean.FALSE);
}
protected String proxyToString(Object proxy) {
return proxy.getClass().getName() + '@' +
Integer.toHexString(proxy.hashCode());
}
}