reactor.rx.action.error.FallbackAction Maven / Gradle / Ivy
/*
* Copyright (c) 2011-2015 Pivotal Software Inc., Inc. All Rights Reserved.
*
* 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.error;
import org.reactivestreams.Publisher;
import reactor.rx.action.Action;
/**
* @author Stephane Maldini
* @since 2.0
*/
public class FallbackAction extends Action {
protected final Publisher fallback;
private boolean switched = false;
private long pendingRequests = 0l;
public FallbackAction(Publisher fallback) {
this.fallback = fallback;
}
@Override
protected void doNext(T ev) {
boolean toSwitch;
synchronized (this){
if(pendingRequests > 0 && pendingRequests != Long.MAX_VALUE){
pendingRequests--;
}
toSwitch = switched;
}
if(toSwitch){
doFallbackNext(ev);
}else{
doNormalNext(ev);
}
}
@Override
protected void requestUpstream(long capacity, boolean terminated, long elements) {
synchronized (this) {
if ((pendingRequests += elements) < 0) pendingRequests = Long.MAX_VALUE;
}
super.requestUpstream(capacity, terminated, elements);
}
protected void doSwitch(){
this.cancel();
long pending;
synchronized (this){
this.switched = true;
pending = pendingRequests;
}
fallback.subscribe(this);
if(pending > 0){
upstreamSubscription.request(pending);
}
}
protected void doNormalNext(T ev) {
broadcastNext(ev);
}
protected void doFallbackNext(T ev) {
broadcastNext(ev);
}
}