reactor.rx.stream.RangeStream 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.stream;
import org.reactivestreams.Subscriber;
import reactor.core.reactivestreams.PublisherFactory;
import reactor.core.reactivestreams.SubscriberWithContext;
import reactor.fn.Consumer;
import reactor.fn.Function;
import reactor.rx.Stream;
import reactor.rx.Streams;
/**
* A Stream that emits N {@link java.lang.Long} from the inclusive start value defined to the inclusive end and then
* complete.
*
* Since the stream retains the boundaries in a final field, any {@link org.reactivestreams.Subscriber}
* will replay all the range. This is a "Cold" stream.
*
* Create such stream with the provided factory, E.g.:
*
* {@code
* Streams.range(1, 10000).consume(
* log::info,
* log::error,
* (-> log.info("complete"))
* )
* }
*
*
* {@code
* Will log:
* 1
* 2
* 3
* 4
* complete
* }
*
*
* @author Stephane Maldini
*/
public final class RangeStream {
/**
* Create a Range Stream Publisher
*
* @param min
* @param max
* @return
*/
public static Stream create(final long min, final long max) {
return Streams.wrap(PublisherFactory.forEach(new Consumer>() {
@Override
public void accept(SubscriberWithContext subscriber) {
Range range = subscriber.context();
if (range.cursor <= range.end) {
subscriber.onNext(range.cursor++);
}
if (range.cursor > range.end) {
subscriber.onComplete();
}
}
}, new Function, Range>() {
@Override
public Range apply(Subscriber subscriber) {
if (max < min) {
subscriber.onComplete();
throw PublisherFactory.PrematureCompleteException.INSTANCE;
}
return new Range(min, max);
}
})
);
}
private final static class Range {
final long start;
final long end;
long cursor;
public Range(long start, long end) {
this.start = start;
this.end = end;
cursor = start;
}
@Override
public String toString() {
return "{" +
"cursor=" + cursor + "" + (end > 0 ? "[" + 100 * (cursor - 1) / end + "%]" : "") +
", start=" + start + ", end=" + end + "}";
}
}
}