/*
* JBoss, Home of Professional Open Source.
* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* Licensed 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 io.undertow.websockets.jsr.util;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.List;
import java.util.Map;
import javax.websocket.Decoder;
import javax.websocket.Encoder;
import javax.websocket.MessageHandler;
import io.undertow.websockets.jsr.JsrWebSocketMessages;
/**
* @author <a href="mailto:nmaurer@redhat.com">Norman Maurer</a>
*/
public final class ClassUtils {
private ClassUtils() {
}
/**
* Returns a map of all supported message types by the given handler class.
* The key of the map is the supported message type; the value indicates
* whether it is a partial message handler or not.
*
* @return a map of all supported message types by the given handler class.
*/
public static Map<Class<?>, Boolean> getHandlerTypes(Class<? extends MessageHandler> clazz) {
Map<Class<?>, Boolean> types = new IdentityHashMap<>(2);
for (Class<?> c = clazz; c != Object.class; c = c.getSuperclass()) {
exampleGenericInterfaces(types, c, clazz);
}
if (types.isEmpty()) {
throw JsrWebSocketMessages.MESSAGES.unknownHandlerType(clazz);
}
return types;
}
private static void exampleGenericInterfaces(Map<Class<?>, Boolean> types, Class<?> c, Class actualClass) {
for (Type type : c.getGenericInterfaces()) {
if (type instanceof ParameterizedType) {
ParameterizedType pt = (ParameterizedType) type;
Type rawType = pt.getRawType();
if (rawType == MessageHandler.Whole.class) {
Type messageType = pt.getActualTypeArguments()[0];
types.put(resolvePotentialTypeVariable(messageType, c, actualClass), Boolean.FALSE);
} else if (rawType == MessageHandler.Partial.class) {
Type messageType = pt.getActualTypeArguments()[0];
types.put(resolvePotentialTypeVariable(messageType, c, actualClass), Boolean.TRUE);
} else if(rawType instanceof Class) {
Class rawClass = (Class) rawType;
if(rawClass.getGenericInterfaces() != null) {
exampleGenericInterfaces(types, rawClass, actualClass);
}
}
} else if(type instanceof Class) {
exampleGenericInterfaces(types, (Class)type, actualClass);
}
}
}
private static Class<?> resolvePotentialTypeVariable(Type messageType, Class<?> c, Class actualClass) {
if(messageType instanceof Class) {
return (Class<?>) messageType;
} else if(messageType instanceof TypeVariable) {
Type var = messageType;
int tvpos = 0;
List<Class> parents = new ArrayList<>();
Class i = actualClass;
while (i != c) {
parents.add(i);
i = i.getSuperclass();
}
Collections.reverse(parents);
for(Class ptype : parents) {
Type type = ptype.getGenericSuperclass();
if(!(type instanceof ParameterizedType)) {
throw JsrWebSocketMessages.MESSAGES.unknownHandlerType(actualClass);
}
ParameterizedType pt = (ParameterizedType) type;
if(tvpos == -1) {
TypeVariable[] typeParameters = ((Class) pt.getRawType()).getTypeParameters();
for(int j = 0; j < typeParameters.length; ++j) {
TypeVariable tp = typeParameters[j];
if(tp.getName().equals(((TypeVariable)var).getName())) {
tvpos = j;
break;
}
}
}
var = pt.getActualTypeArguments()[tvpos];
if(var instanceof Class) {
return (Class<?>) var;
}
tvpos = -1;
}
return (Class<?>) var;
} else {
throw JsrWebSocketMessages.MESSAGES.unknownHandlerType(actualClass);
}
}
/**
* Returns the Object type for which the {@link Encoder} can be used.
*/
public static Class<?> getEncoderType(Class<? extends Encoder> clazz) {
Method[] methods = clazz.getMethods();
for (Method m : methods) {
if ("encode".equals(m.getName()) && !m.isBridge()) {
return m.getParameterTypes()[0];
}
}
throw JsrWebSocketMessages.MESSAGES.unknownEncoderType(clazz);
}
/**
* Returns the Object type for which the {@link Encoder} can be used.
*/
public static Class<?> getDecoderType(Class<? extends Decoder> clazz) {
Method[] methods = clazz.getMethods();
for (Method m : methods) {
if ("decode".equals(m.getName()) && !m.isBridge()) {
return m.getReturnType();
}
}
throw JsrWebSocketMessages.MESSAGES.couldNotDetermineDecoderTypeFor(clazz);
}
}