reactor.rx.action.transformation.GroupByAction Maven / Gradle / Ivy
/*
* Copyright (c) 2011-2014 Pivotal Software, Inc.
*
* 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 reactor.rx.action.transformation;
import org.reactivestreams.Subscriber;
import reactor.Environment;
import reactor.core.Dispatcher;
import reactor.core.queue.CompletableQueue;
import reactor.core.reactivestreams.SerializedSubscriber;
import reactor.core.support.Assert;
import reactor.fn.Function;
import reactor.rx.action.Action;
import reactor.rx.action.support.DefaultSubscriber;
import reactor.rx.stream.GroupedStream;
import reactor.rx.subscription.PushSubscription;
import reactor.rx.subscription.ReactiveSubscription;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* Manage a dynamic registry of substreams for a given key extracted from the incoming data. Each non-existing key
* will result in a new stream to be signaled
*
* @param
* @param
* @since 2.0
*/
public class GroupByAction extends Action> {
private final Function fn;
private final Environment environment;
private final Dispatcher dispatcher;
private final Map> groupByMap = new ConcurrentHashMap<>();
private final SerializedSubscriber serialized = SerializedSubscriber.create(new DefaultSubscriber
() {
@Override
public void onNext(Long aLong) {
checkRequest(aLong);
if(upstreamSubscription != null){
upstreamSubscription.request(aLong );
}
}
});
public GroupByAction(Environment environment, Function fn, Dispatcher dispatcher) {
Assert.notNull(fn, "Key mapping function cannot be null.");
this.dispatcher = dispatcher;
this.fn = fn;
this.environment = environment;
}
public Map> groupByMap() {
return groupByMap;
}
@Override
protected void doNext(final T value) {
final K key = fn.apply(value);
ReactiveSubscription child = groupByMap.get(key);
if (child == null) {
child = new ReactiveSubscription(null, null);
child.getBuffer().add(value);
groupByMap.put(key, child);
final CompletableQueue queue = child.getBuffer();
GroupedStream action = new GroupedStream(key) {
@Override
public long getCapacity() {
return GroupByAction.this.getCapacity();
}
@Override
public Dispatcher getDispatcher() {
return dispatcher;
}
@Override
public Environment getEnvironment() {
return environment;
}
@Override
public void subscribe(Subscriber s) {
final AtomicBoolean last = new AtomicBoolean();
ReactiveSubscription finalSub = new ReactiveSubscription(this, s, queue) {
@Override
public void cancel() {
super.cancel();
if (last.compareAndSet(false, true)) {
removeGroupedStream(key);
}
}
@Override
public void onComplete() {
super.onComplete();
if (last.compareAndSet(false, true)) {
removeGroupedStream(key);
}
}
@Override
protected void onRequest(long n) {
serialized.onNext(n);
}
};
//finalSub.maxCapacity(capacity);
groupByMap.put(key, finalSub);
s.onSubscribe(finalSub);
}
};
broadcastNext(action);
} else {
child.onNext(value);
}
}
private void removeGroupedStream(K key) {
PushSubscription parentSub = upstreamSubscription;
ReactiveSubscription innerSub = groupByMap.remove(key);
if (innerSub != null
&& groupByMap.isEmpty() &&
((parentSub == null || parentSub.isComplete()))) {
PushSubscription> childSub = downstreamSubscription;
if (childSub == null || childSub.isComplete()) {
cancel();
}
if (innerSub.getBufferSize() == 0l) {
broadcastComplete();
}
}
}
@Override
protected void doComplete() {
for (ReactiveSubscription stream : groupByMap.values()) {
stream.onComplete();
}
super.doComplete();
}
@Override
public void requestMore(long n) {
serialized.onNext(n);
}
@Override
public final Dispatcher getDispatcher() {
return dispatcher;
}
@Override
public final Environment getEnvironment() {
return environment;
}
}