/*
* Copyright 2012 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.gradle.messaging.remote.internal.hub.queue;
import org.gradle.messaging.dispatch.Dispatch;
import org.gradle.messaging.remote.internal.hub.protocol.EndOfStream;
import org.gradle.messaging.remote.internal.hub.protocol.InterHubMessage;
import java.util.*;
import java.util.concurrent.locks.Lock;
// TODO - use circular buffers to avoid copying
// TODO - share a single initializer with MultiChannelQueue
public class MultiEndPointQueue implements Dispatch<InterHubMessage> {
private final Set<EndPointQueue> endpoints = new HashSet<EndPointQueue>();
private final List<InterHubMessage> queue = new ArrayList<InterHubMessage>();
private final List<EndPointQueue> waiting = new ArrayList<EndPointQueue>();
private final Lock lock;
private final QueueInitializer initializer = new QueueInitializer();
public MultiEndPointQueue(Lock lock) {
this.lock = lock;
}
public void dispatch(InterHubMessage message) {
queue.add(message);
flush();
}
void empty(EndPointQueue endPointQueue) {
waiting.add(endPointQueue);
flush();
}
void stopped(EndPointQueue queue) {
waiting.remove(queue);
endpoints.remove(queue);
queue.dispatch(new EndOfStream());
}
public void drain(Collection<InterHubMessage> drainTo) {
drainTo.addAll(queue);
queue.clear();
}
private void flush() {
// TODO - need to do a better job of routing messages when there are multiple endpoints. This is just going to forward all queued messages to the first
// waiting endpoint, even if there are multiple waiting to do work
EndPointQueue selected = waiting.isEmpty() ? null : waiting.get(0);
while (!queue.isEmpty()) {
InterHubMessage message = queue.get(0);
switch (message.getDelivery()) {
case Stateful:
case AllHandlers:
if (endpoints.isEmpty()) {
return;
}
if (message.getDelivery() == InterHubMessage.Delivery.Stateful) {
initializer.onStatefulMessage(message);
}
for (EndPointQueue endpoint : endpoints) {
endpoint.dispatch(message);
}
queue.remove(0);
waiting.clear();
continue;
case SingleHandler:
if (selected == null) {
return;
}
queue.remove(0);
waiting.remove(selected);
selected.dispatch(message);
break;
default:
throw new IllegalArgumentException("Unknown delivery type: " + message.getDelivery());
}
}
}
public EndPointQueue newEndpoint() {
EndPointQueue endPointQueue = new EndPointQueue(this, lock.newCondition());
endpoints.add(endPointQueue);
initializer.onQueueAdded(endPointQueue);
return endPointQueue;
}
}