org.apache.cxf.common.util.ReflectionInvokationHandler Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.cxf.common.util;
import java.lang.annotation.Annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Iterator;
/**
*
*/
public class ReflectionInvokationHandler implements InvocationHandler {
private Object target;
public ReflectionInvokationHandler(Object obj) {
target = obj;
}
public Object getTarget() {
return target;
}
/** {@inheritDoc}*/
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
WrapReturn wr = method.getAnnotation(WrapReturn.class);
final Class targetClass = target.getClass();
Class[] parameterTypes = getParameterTypes(method, args);
try {
Method m;
try {
m = targetClass.getMethod(method.getName(), parameterTypes);
} catch (NoSuchMethodException nsme) {
boolean[] optionals = new boolean[method.getParameterTypes().length];
int i = 0;
int optionalNumber = 0;
for (final Annotation[] a : method.getParameterAnnotations()) {
optionals[i] = false;
for (final Annotation potential : a) {
if (Optional.class.equals(potential.annotationType())) {
optionals[i] = true;
optionalNumber++;
break;
}
}
i++;
}
Class[] newParams = new Class[args.length - optionalNumber];
Object[] newArgs = new Object[args.length - optionalNumber];
int argI = 0;
for (int j = 0; j < parameterTypes.length; j++) {
if (optionals[j]) {
continue;
}
newArgs[argI] = args[j];
newParams[argI] = parameterTypes[j];
argI++;
}
m = targetClass.getMethod(method.getName(), newParams);
args = newArgs;
parameterTypes = newParams;
}
ReflectionUtil.setAccessible(m);
return wrapReturn(wr, m.invoke(target, args));
} catch (InvocationTargetException e) {
throw e.getCause();
} catch (NoSuchMethodException e) {
for (Method m2 : targetClass.getMethods()) {
if (m2.getName().equals(method.getName())
&& m2.getParameterTypes().length == method.getParameterTypes().length) {
boolean found = true;
for (int x = 0; x < m2.getParameterTypes().length; x++) {
if (args[x] != null
&& !m2.getParameterTypes()[x].isInstance(args[x])) {
found = false;
}
}
if (found) {
ReflectionUtil.setAccessible(m2);
return wrapReturn(wr, m2.invoke(target, args));
}
}
}
throw e;
}
}
private Class[] getParameterTypes(Method method, Object[] args) {
Class[] types = method.getParameterTypes();
for (int x = 0; x < types.length; x++) {
UnwrapParam p = getUnwrapParam(method.getParameterAnnotations()[x]);
if (p != null) {
String s = p.methodName();
String tn = p.typeMethodName();
try {
Method m = args[x].getClass().getMethod(s);
if ("#default".equals(tn)) {
types[x] = m.getReturnType();
} else {
Method m2 = args[x].getClass().getMethod(tn);
types[x] = (Class)ReflectionUtil.setAccessible(m2).invoke(args[x]);
}
args[x] = ReflectionUtil.setAccessible(m).invoke(args[x]);
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
}
return types;
}
private UnwrapParam getUnwrapParam(Annotation[] annotations) {
for (Annotation a : annotations) {
if (a instanceof UnwrapParam) {
return (UnwrapParam)a;
}
}
return null;
}
private static Object wrapReturn(WrapReturn wr, Object t) {
if (wr == null || t == null) {
return t;
}
if (wr.iterator()) {
return new WrapperIterator(wr.value(), (Iterator)t);
}
return createProxyWrapper(t, wr.value());
}
public static T createProxyWrapper(Object target, Class inf) {
InvocationHandler h = new ReflectionInvokationHandler(target);
return inf.cast(Proxy.newProxyInstance(inf.getClassLoader(), new Class[] {inf}, h));
}
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public static @interface Optional {
}
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public static @interface WrapReturn {
Class value();
boolean iterator() default false;
}
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public static @interface UnwrapParam {
String methodName() default "getValue";
String typeMethodName() default "#default";
}
private static class WrapperIterator implements Iterator