/**
* Copyright 2015 Netflix, Inc.
* <p/>
* 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
* <p/>
* http://www.apache.org/licenses/LICENSE-2.0
* <p/>
* 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 com.netflix.hystrix.metric.consumer;
import com.netflix.hystrix.metric.HystrixEvent;
import com.netflix.hystrix.metric.HystrixEventStream;
import rx.Observable;
import rx.functions.Action0;
import rx.functions.Func2;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* Refinement of {@link BucketedCounterStream} which accumulates counters infinitely in the bucket-reduction step
*
* @param <Event> type of raw data that needs to get summarized into a bucket
* @param <Bucket> type of data contained in each bucket
* @param <Output> type of data emitted to stream subscribers (often is the same as A but does not have to be)
*/
public abstract class BucketedCumulativeCounterStream<Event extends HystrixEvent, Bucket, Output> extends BucketedCounterStream<Event, Bucket, Output> {
private Observable<Output> sourceStream;
private final AtomicBoolean isSourceCurrentlySubscribed = new AtomicBoolean(false);
protected BucketedCumulativeCounterStream(HystrixEventStream<Event> stream, int numBuckets, int bucketSizeInMs,
Func2<Bucket, Event, Bucket> reduceCommandCompletion,
Func2<Output, Bucket, Output> reduceBucket) {
super(stream, numBuckets, bucketSizeInMs, reduceCommandCompletion);
this.sourceStream = bucketedStream
.scan(getEmptyOutputValue(), reduceBucket)
.skip(numBuckets)
.doOnSubscribe(new Action0() {
@Override
public void call() {
isSourceCurrentlySubscribed.set(true);
}
})
.doOnUnsubscribe(new Action0() {
@Override
public void call() {
isSourceCurrentlySubscribed.set(false);
}
})
.share() //multiple subscribers should get same data
.onBackpressureDrop(); //if there are slow consumers, data should not buffer
}
@Override
public Observable<Output> observe() {
return sourceStream;
}
}