public void testMethodKey() throws Exception {
MethodKey factory = (MethodKey) KeyFactory.create(MethodKey.class);
Set methodSet = new HashSet();
methodSet.add(factory.newInstance(Number.class, new Class[] {int.class}));
assertTrue(methodSet.contains(factory.newInstance(Number.class, new Class[] {int.class})));
assertTrue(!methodSet.contains(factory.newInstance(Number.class, new Class[] {Integer.class})));
}
public void testSimple() throws Exception {
MyKey mykey = (MyKey) KeyFactory.create(MyKey.class);
assertTrue(
mykey.newInstance(5, new int[] {6, 7}, false).hashCode()
== mykey.newInstance(5, new int[] {6, 7}, false).hashCode());
}
public void perform(ClassLoader loader) throws Throwable {
KeyFactory.create(loader, MyKey.class, null);
}
public void testEqualOtherClass() throws Exception {
MyKey mykey = (MyKey) KeyFactory.create(MyKey.class);
assertTrue(!mykey.newInstance(5, new int[] {6, 7}, false).equals(new Object()));
}
public void testBooleanArray() throws Exception {
BooleanArrayKey f = (BooleanArrayKey) KeyFactory.create(BooleanArrayKey.class);
Object key1 = f.newInstance(new boolean[] {true, false, true});
Object key2 = f.newInstance(new boolean[] {true, false, true});
assertTrue(key1.equals(key2));
}
public void testCharArray() throws Exception {
CharArrayKey f = (CharArrayKey) KeyFactory.create(CharArrayKey.class);
Object key1 = f.newInstance(new char[] {'a', 'b'});
Object key2 = f.newInstance(new char[] {'a', '_'});
assertTrue(!key1.equals(key2));
}
/**
* <b>DOCUMENTATION FROM APACHE AVALON DELEGATE CLASS</b>
*
* <p>Delegates are a typesafe pointer to another method. Since Java does not have language support
* for such a construct, this utility will construct a proxy that forwards method calls to any
* method with the same signature. This utility is inspired in part by the C# delegate mechanism. We
* implemented it in a Java-centric manner.
*
* <h2>Delegate</h2>
*
* <p>Any interface with one method can become the interface for a delegate. Consider the example
* below:
*
* <pre>
* public interface MainDelegate {
* int main(String[] args);
* }
* </pre>
*
* <p>The interface above is an example of an interface that can become a delegate. It has only one
* method, and the interface is public. In order to create a delegate for that method, all we have
* to do is call <code>MethodDelegate.create(this, "alternateMain", MainDelegate.class)</code>. The
* following program will show how to use it:
*
* <pre>
* public class Main {
* public static int main( String[] args ) {
* Main newMain = new Main();
* MainDelegate start = (MainDelegate)
* MethodDelegate.create(newMain, "alternateMain", MainDelegate.class);
* return start.main( args );
* }
*
* public int alternateMain( String[] args ) {
* for (int i = 0; i < args.length; i++) {
* System.out.println( args[i] );
* }
* return args.length;
* }
* }
* </pre>
*
* <p>By themselves, delegates don't do much. Their true power lies in the fact that they can be
* treated like objects, and passed to other methods. In fact that is one of the key building blocks
* of building Intelligent Agents which in tern are the foundation of artificial intelligence. In
* the above program, we could have easily created the delegate to match the static <code>main
* </code> method by substituting the delegate creation call with this: <code>
* MethodDelegate.createStatic(getClass(), "main", MainDelegate.class)</code>.
*
* <p>Another key use for Delegates is to register event listeners. It is much easier to have all
* the code for your events separated out into methods instead of individual classes. One of the
* ways Java gets around that is to create anonymous classes. They are particularly troublesome
* because many Debuggers do not know what to do with them. Anonymous classes tend to duplicate alot
* of code as well. We can use any interface with one declared method to forward events to any
* method that matches the signature (although the method name can be different).
*
* <h3>Equality</h3>
*
* The criteria that we use to test if two delegates are equal are:
*
* <ul>
* <li>They both refer to the same instance. That is, the <code>instance</code> parameter passed
* to the newDelegate method was the same for both. The instances are compared with the
* identity equality operator, <code>==</code>.
* <li>They refer to the same method as resolved by <code>Method.equals</code>.
* </ul>
*
* @version $Id: MethodDelegate.java,v 1.25 2006/03/05 02:43:19 herbyderby Exp $
*/
public abstract class MethodDelegate {
private static final MethodDelegateKey KEY_FACTORY =
(MethodDelegateKey) KeyFactory.create(MethodDelegateKey.class, KeyFactory.CLASS_BY_NAME);
protected Object target;
protected String eqMethod;
interface MethodDelegateKey {
Object newInstance(Class delegateClass, String methodName, Class iface);
}
public static MethodDelegate createStatic(Class targetClass, String methodName, Class iface) {
Generator gen = new Generator();
gen.setTargetClass(targetClass);
gen.setMethodName(methodName);
gen.setInterface(iface);
return gen.create();
}
public static MethodDelegate create(Object target, String methodName, Class iface) {
Generator gen = new Generator();
gen.setTarget(target);
gen.setMethodName(methodName);
gen.setInterface(iface);
return gen.create();
}
public boolean equals(Object obj) {
MethodDelegate other = (MethodDelegate) obj;
return target == other.target && eqMethod.equals(other.eqMethod);
}
public int hashCode() {
return target.hashCode() ^ eqMethod.hashCode();
}
public Object getTarget() {
return target;
}
public abstract MethodDelegate newInstance(Object target);
public static class Generator extends AbstractClassGenerator {
private static final Source SOURCE = new Source(MethodDelegate.class.getName());
private static final Type METHOD_DELEGATE =
TypeUtils.parseType("net.sf.cglib.reflect.MethodDelegate");
private static final Signature NEW_INSTANCE =
new Signature("newInstance", METHOD_DELEGATE, new Type[] {Constants.TYPE_OBJECT});
private Object target;
private Class targetClass;
private String methodName;
private Class iface;
public Generator() {
super(SOURCE);
}
public void setTarget(Object target) {
this.target = target;
this.targetClass = target.getClass();
}
public void setTargetClass(Class targetClass) {
this.targetClass = targetClass;
}
public void setMethodName(String methodName) {
this.methodName = methodName;
}
public void setInterface(Class iface) {
this.iface = iface;
}
protected ClassLoader getDefaultClassLoader() {
return targetClass.getClassLoader();
}
protected ProtectionDomain getProtectionDomain() {
return ReflectUtils.getProtectionDomain(targetClass);
}
public MethodDelegate create() {
setNamePrefix(targetClass.getName());
Object key = KEY_FACTORY.newInstance(targetClass, methodName, iface);
return (MethodDelegate) super.create(key);
}
protected Object firstInstance(Class type) {
return ((MethodDelegate) ReflectUtils.newInstance(type)).newInstance(target);
}
protected Object nextInstance(Object instance) {
return ((MethodDelegate) instance).newInstance(target);
}
public void generateClass(ClassVisitor v) throws NoSuchMethodException {
Method proxy = ReflectUtils.findInterfaceMethod(iface);
final Method method = targetClass.getMethod(methodName, proxy.getParameterTypes());
if (!proxy.getReturnType().isAssignableFrom(method.getReturnType())) {
throw new IllegalArgumentException("incompatible return types");
}
MethodInfo methodInfo = ReflectUtils.getMethodInfo(method);
boolean isStatic = TypeUtils.isStatic(methodInfo.getModifiers());
if ((target == null) ^ isStatic) {
throw new IllegalArgumentException(
"Static method " + (isStatic ? "not " : "") + "expected");
}
ClassEmitter ce = new ClassEmitter(v);
CodeEmitter e;
ce.begin_class(
Constants.V1_2,
Constants.ACC_PUBLIC,
getClassName(),
METHOD_DELEGATE,
new Type[] {Type.getType(iface)},
Constants.SOURCE_FILE);
ce.declare_field(Constants.PRIVATE_FINAL_STATIC, "eqMethod", Constants.TYPE_STRING, null);
EmitUtils.null_constructor(ce);
// generate proxied method
MethodInfo proxied = ReflectUtils.getMethodInfo(iface.getDeclaredMethods()[0]);
int modifiers = Constants.ACC_PUBLIC;
if ((proxied.getModifiers() & Constants.ACC_VARARGS) == Constants.ACC_VARARGS) {
modifiers |= Constants.ACC_VARARGS;
}
e = EmitUtils.begin_method(ce, proxied, modifiers);
e.load_this();
e.super_getfield("target", Constants.TYPE_OBJECT);
e.checkcast(methodInfo.getClassInfo().getType());
e.load_args();
e.invoke(methodInfo);
e.return_value();
e.end_method();
// newInstance
e = ce.begin_method(Constants.ACC_PUBLIC, NEW_INSTANCE, null);
e.new_instance_this();
e.dup();
e.dup2();
e.invoke_constructor_this();
e.getfield("eqMethod");
e.super_putfield("eqMethod", Constants.TYPE_STRING);
e.load_arg(0);
e.super_putfield("target", Constants.TYPE_OBJECT);
e.return_value();
e.end_method();
// static initializer
e = ce.begin_static();
e.push(methodInfo.getSignature().toString());
e.putfield("eqMethod");
e.return_value();
e.end_method();
ce.end_class();
}
}
}
