rx.internal.operators.OperatorTakeLastTimed Maven / Gradle / Ivy
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/**
* Copyright 2014 Netflix, 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 rx.internal.operators;
import rx.Observable.Operator;
import rx.Scheduler;
import rx.Subscriber;
import rx.schedulers.Timestamped;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.concurrent.TimeUnit;
/**
* Returns an Observable that emits the last count items emitted by the source
* Observable.
*
* 
*/
public final class OperatorTakeLastTimed implements Operator {
private final long ageMillis;
private final Scheduler scheduler;
private final int count;
public OperatorTakeLastTimed(long time, TimeUnit unit, Scheduler scheduler) {
this.ageMillis = unit.toMillis(time);
this.scheduler = scheduler;
this.count = -1;
}
public OperatorTakeLastTimed(int count, long time, TimeUnit unit, Scheduler scheduler) {
if (count < 0) {
throw new IndexOutOfBoundsException("count could not be negative");
}
this.ageMillis = unit.toMillis(time);
this.scheduler = scheduler;
this.count = count;
}
@Override
public Subscriber call(final Subscriber subscriber) {
return new Subscriber(subscriber) {
private final Deque> buffer = new ArrayDeque>();
protected void runEvictionPolicy(long now) {
// trim size
while (count >= 0 && buffer.size() > count) {
buffer.pollFirst();
}
// remove old entries
while (!buffer.isEmpty()) {
Timestamped v = buffer.peekFirst();
if (v.getTimestampMillis() < now - ageMillis) {
buffer.pollFirst();
} else {
break;
}
}
}
@Override
public void onNext(T args) {
long t = scheduler.now();
buffer.add(new Timestamped(t, args));
runEvictionPolicy(t);
}
@Override
public void onError(Throwable e) {
buffer.clear();
subscriber.onError(e);
}
@Override
public void onCompleted() {
runEvictionPolicy(scheduler.now());
try {
for (Timestamped v : buffer) {
subscriber.onNext(v.getValue());
}
} catch (Throwable e) {
onError(e);
return;
}
buffer.clear();
subscriber.onCompleted();
}
};
}
}