org.cometd.annotation.ClientAnnotationProcessor Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2020 the original author or authors.
*
* 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 org.cometd.annotation;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import org.cometd.bayeux.Channel;
import org.cometd.bayeux.ChannelId;
import org.cometd.bayeux.Message;
import org.cometd.bayeux.client.ClientSession;
import org.cometd.bayeux.client.ClientSessionChannel;
/**
* Processes annotations in client-side service objects.
* Service objects must be annotated with {@link Service} at class level to be processed by this processor,
* for example:
*
* @Service
* public class MyService
* {
* @Listener(Channel.META_CONNECT)
* public void metaConnect(Message message)
* {
* // Do something
* }
* }
*
* The processor is used in this way:
*
* ClientSession bayeux = ...;
* ClientAnnotationProcessor processor = ClientAnnotationProcessor.get(bayeux);
* MyService s = new MyService();
* processor.process(s);
*
*
* @see ServerAnnotationProcessor
*/
public class ClientAnnotationProcessor extends AnnotationProcessor {
private final ConcurrentMap handshakeListeners = new ConcurrentHashMap<>();
private final ConcurrentMap> listeners = new ConcurrentHashMap<>();
private final ConcurrentMap> subscribers = new ConcurrentHashMap<>();
private final ClientSession clientSession;
private final Object[] injectables;
public ClientAnnotationProcessor(ClientSession clientSession) {
this(clientSession, new Object[0]);
}
public ClientAnnotationProcessor(ClientSession clientSession, Object... injectables) {
this.clientSession = clientSession;
this.injectables = injectables;
}
/**
* Processes dependencies annotated with {@link Session}, callbacks
* annotated with {@link Listener} and {@link Subscription} and lifecycle
* methods annotated with {@link PostConstruct}.
*
* @param bean the annotated service instance
* @return true if at least one dependency or callback has been processed, false otherwise
*/
public boolean process(Object bean) {
processMetaHandshakeListener(bean);
boolean result = processDependencies(bean);
result |= processCallbacks(bean);
result |= processPostConstruct(bean);
return result;
}
private void processMetaHandshakeListener(Object bean) {
if (bean != null) {
MetaHandshakeListener listener = new MetaHandshakeListener(bean);
ClientSessionChannel.MessageListener existing = handshakeListeners.putIfAbsent(bean, listener);
if (existing == null) {
clientSession.getChannel(Channel.META_HANDSHAKE).addListener(listener);
}
}
}
/**
* Processes lifecycle methods annotated with {@link PostConstruct}.
*
* @param bean the annotated service instance
* @return true if at least one lifecycle method has been invoked, false otherwise
*/
@Override
public boolean processPostConstruct(Object bean) {
return super.processPostConstruct(bean);
}
private boolean processCallbacks(Object bean) {
if (bean == null) {
return false;
}
Class klass = bean.getClass();
Service serviceAnnotation = klass.getAnnotation(Service.class);
if (serviceAnnotation == null) {
return false;
}
if (!Modifier.isPublic(klass.getModifiers())) {
throw new IllegalArgumentException("Service class " + klass.getName() + " must be public");
}
boolean result = processListener(bean);
result |= processSubscription(bean);
return result;
}
/**
* Performs the opposite processing done by {@link #process(Object)} on callbacks methods
* annotated with {@link Listener} and {@link Subscription}, and on lifecycle methods annotated
* with {@link PreDestroy}.
*
* @param bean the annotated service instance
* @return true if at least one deprocessing has been performed, false otherwise
* @see #process(Object)
*/
public boolean deprocess(Object bean) {
deprocessMetaHandshakeListener(bean);
boolean result = deprocessCallbacks(bean);
result |= processPreDestroy(bean);
return result;
}
private void deprocessMetaHandshakeListener(Object bean) {
ClientSessionChannel.MessageListener listener = handshakeListeners.remove(bean);
if (listener != null) {
clientSession.getChannel(Channel.META_HANDSHAKE).removeListener(listener);
}
}
/**
* Performs the opposite processing done by {@link #processCallbacks(Object)}
* on callback methods annotated with {@link Listener} and {@link Subscription}.
*
* @param bean the annotated service instance
* @return true if the at least one callback has been deprocessed
*/
public boolean deprocessCallbacks(Object bean) {
boolean result = deprocessListener(bean);
result |= deprocessSubscription(bean);
return result;
}
/**
* Processes lifecycle methods annotated with {@link PreDestroy}.
*
* @param bean the annotated service instance
* @return true if at least one lifecycle method has been invoked, false otherwise
*/
@Override
public boolean processPreDestroy(Object bean) {
return super.processPreDestroy(bean);
}
private boolean processDependencies(Object bean) {
if (bean == null) {
return false;
}
Class klass = bean.getClass();
Service serviceAnnotation = klass.getAnnotation(Service.class);
if (serviceAnnotation == null) {
return false;
}
boolean result = processInjectables(bean, Arrays.asList(injectables));
result |= processSession(bean, clientSession);
return result;
}
private boolean processSession(Object bean, ClientSession clientSession) {
boolean result = false;
for (Class c = bean.getClass(); c != Object.class; c = c.getSuperclass()) {
Field[] fields = c.getDeclaredFields();
for (Field field : fields) {
if (field.getAnnotation(Session.class) != null) {
if (field.getType().isAssignableFrom(clientSession.getClass())) {
setField(bean, field, clientSession);
result = true;
if (logger.isDebugEnabled()) {
logger.debug("Injected {} to field {} on bean {}", clientSession, field, bean);
}
}
}
}
}
List methods = findAnnotatedMethods(bean, Session.class);
for (Method method : methods) {
Class[] parameterTypes = method.getParameterTypes();
if (parameterTypes.length == 1) {
if (parameterTypes[0].isAssignableFrom(clientSession.getClass())) {
invokePrivate(bean, method, clientSession);
result = true;
if (logger.isDebugEnabled()) {
logger.debug("Injected {} to method {} on bean {}", clientSession, method, bean);
}
}
}
}
return result;
}
private boolean processListener(Object bean) {
checkMethodsPublic(bean, Listener.class);
boolean result = false;
Method[] methods = bean.getClass().getMethods();
for (Method method : methods) {
if (method.getDeclaringClass() == Object.class) {
continue;
}
Listener listener = method.getAnnotation(Listener.class);
if (listener != null) {
List paramNames = processParameters(method);
checkSignaturesMatch(method, ListenerCallback.signature, paramNames);
String[] channels = listener.value();
for (String channel : channels) {
if (!ChannelId.isMeta(channel)) {
throw new IllegalArgumentException("Annotation @" + Listener.class.getSimpleName() +
" on method " + method.getDeclaringClass().getName() + "." + method.getName() +
"(...) must specify a meta channel");
}
ChannelId channelId = new ChannelId(channel);
if (channelId.isTemplate()) {
channel = channelId.getWilds().get(0);
}
ListenerCallback listenerCallback = new ListenerCallback(bean, method, paramNames, channelId, channel);
clientSession.getChannel(channel).addListener(listenerCallback);
List callbacks = listeners.get(bean);
if (callbacks == null) {
callbacks = new CopyOnWriteArrayList<>();
List existing = listeners.putIfAbsent(bean, callbacks);
if (existing != null) {
callbacks = existing;
}
}
callbacks.add(listenerCallback);
result = true;
if (logger.isDebugEnabled()) {
logger.debug("Registered listener for channel {} to method {} on bean {}", channel, method, bean);
}
}
}
}
return result;
}
private boolean deprocessListener(Object bean) {
boolean result = false;
List callbacks = listeners.remove(bean);
if (callbacks != null) {
for (ListenerCallback callback : callbacks) {
ClientSessionChannel channel = clientSession.getChannel(callback.subscription);
if (channel != null) {
channel.removeListener(callback);
result = true;
}
}
}
return result;
}
private boolean processSubscription(Object bean) {
checkMethodsPublic(bean, Subscription.class);
boolean result = false;
Method[] methods = bean.getClass().getMethods();
for (Method method : methods) {
if (method.getDeclaringClass() == Object.class) {
continue;
}
Subscription subscription = method.getAnnotation(Subscription.class);
if (subscription != null) {
List paramNames = processParameters(method);
checkSignaturesMatch(method, SubscriptionCallback.signature, paramNames);
String[] channels = subscription.value();
for (String channel : channels) {
if (ChannelId.isMeta(channel)) {
throw new IllegalArgumentException("Annotation @" + Subscription.class.getSimpleName() +
" on method " + method.getDeclaringClass().getName() + "." + method.getName() +
"(...) must specify a non meta channel");
}
ChannelId channelId = new ChannelId(channel);
if (channelId.isTemplate()) {
channel = channelId.getWilds().get(0);
}
SubscriptionCallback subscriptionCallback = new SubscriptionCallback(clientSession, bean, method, paramNames, channelId, channel);
// We should delay the subscription if the client session did not complete the handshake
if (clientSession.isHandshook()) {
clientSession.getChannel(channel).subscribe(subscriptionCallback);
}
List callbacks = subscribers.get(bean);
if (callbacks == null) {
callbacks = new CopyOnWriteArrayList<>();
List existing = subscribers.putIfAbsent(bean, callbacks);
if (existing != null) {
callbacks = existing;
}
}
callbacks.add(subscriptionCallback);
result = true;
if (logger.isDebugEnabled()) {
logger.debug("Registered subscriber for channel {} to method {} on bean {}", channel, method, bean);
}
}
}
}
return result;
}
private boolean deprocessSubscription(Object bean) {
boolean result = false;
List callbacks = subscribers.remove(bean);
if (callbacks != null) {
for (SubscriptionCallback callback : callbacks) {
clientSession.getChannel(callback.subscription).unsubscribe(callback);
result = true;
}
}
return result;
}
private static class ListenerCallback implements ClientSessionChannel.MessageListener {
private static final Class[] signature = new Class[]{Message.class};
private final Object target;
private final Method method;
private final List paramNames;
private final ChannelId channelId;
private final String subscription;
private ListenerCallback(Object target, Method method, List paramNames, ChannelId channelId, String subscription) {
this.target = target;
this.method = method;
this.paramNames = paramNames;
this.channelId = channelId;
this.subscription = subscription;
}
@Override
public void onMessage(ClientSessionChannel channel, Message message) {
Map matches = channelId.bind(message.getChannelId());
if (!paramNames.isEmpty() && !matches.keySet().containsAll(paramNames)) {
return;
}
Object[] args = new Object[1 + paramNames.size()];
args[0] = message;
for (int i = 0; i < paramNames.size(); ++i) {
args[1 + i] = matches.get(paramNames.get(i));
}
callPublic(target, method, args);
}
}
private static class SubscriptionCallback implements ClientSessionChannel.MessageListener {
private static final Class[] signature = new Class[]{Message.class};
private final ClientSession clientSession;
private final Object target;
private final Method method;
private final List paramNames;
private final ChannelId channelId;
private final String subscription;
public SubscriptionCallback(ClientSession clientSession, Object target, Method method, List paramNames, ChannelId channelId, String subscription) {
this.clientSession = clientSession;
this.target = target;
this.method = method;
this.paramNames = paramNames;
this.channelId = channelId;
this.subscription = subscription;
}
@Override
public void onMessage(ClientSessionChannel channel, Message message) {
Map matches = channelId.bind(message.getChannelId());
if (!paramNames.isEmpty() && !matches.keySet().containsAll(paramNames)) {
return;
}
Object[] args = new Object[1 + paramNames.size()];
args[0] = message;
for (int i = 0; i < paramNames.size(); ++i) {
args[1 + i] = matches.get(paramNames.get(i));
}
callPublic(target, method, args);
}
private void subscribe() {
clientSession.getChannel(subscription).subscribe(this);
}
}
private class MetaHandshakeListener implements ClientSessionChannel.MessageListener {
private final Object bean;
public MetaHandshakeListener(Object bean) {
this.bean = bean;
}
@Override
public void onMessage(ClientSessionChannel channel, Message message) {
if (message.isSuccessful()) {
final List subscriptions = subscribers.get(bean);
if (subscriptions != null) {
clientSession.batch(() -> {
for (SubscriptionCallback subscription : subscriptions) {
subscription.subscribe();
}
});
}
}
}
}
}