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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 java.util.*;

import rx.Observable;
import rx.Observable.Operator;
import rx.Observer;
import rx.Subscriber;
import rx.exceptions.Exceptions;
import rx.functions.Func0;
import rx.observers.*;

/**
 * This operation takes
 * values from the specified {@link Observable} source and stores them in a buffer until the
 * {@link Observable} constructed using the {@link Func0} argument, produces a value. The buffer is then
 * emitted, and a new buffer is created to replace it. A new {@link Observable} will be constructed using
 * the provided {@link Func0} object, which will determine when this new buffer is emitted. When the source
 * {@link Observable} completes or produces an error, the current buffer is emitted, and the event is
 * propagated to all subscribed {@link Observer}s.
 * 

* Note that this operation only produces non-overlapping chunks. At all times there is * exactly one buffer actively storing values. *

* * @param the buffered value type * @param the value type of the Observable signaling the end of each buffer */ public final class OperatorBufferWithSingleObservable implements Operator, T> { final Func0> bufferClosingSelector; final int initialCapacity; /** * @param bufferClosingSelector * a {@link Func0} object which produces {@link Observable}s. These {@link Observable}s determine * when a buffer is emitted and replaced by simply producing an object. * @param initialCapacity the initial capacity of each buffer */ public OperatorBufferWithSingleObservable(Func0> bufferClosingSelector, int initialCapacity) { this.bufferClosingSelector = bufferClosingSelector; this.initialCapacity = initialCapacity; } /** * @param bufferClosing * An {@link Observable} to determine * when a buffer is emitted and replaced by simply producing an object. * @param initialCapacity the initial capacity of each buffer */ public OperatorBufferWithSingleObservable(final Observable bufferClosing, int initialCapacity) { this.bufferClosingSelector = new Func0>() { @Override public Observable call() { return bufferClosing; } }; this.initialCapacity = initialCapacity; } @Override public Subscriber call(final Subscriber> child) { Observable closing; try { closing = bufferClosingSelector.call(); } catch (Throwable t) { Exceptions.throwOrReport(t, child); return Subscribers.empty(); } final BufferingSubscriber bsub = new BufferingSubscriber(new SerializedSubscriber>(child)); Subscriber closingSubscriber = new Subscriber() { @Override public void onNext(TClosing t) { bsub.emit(); } @Override public void onError(Throwable e) { bsub.onError(e); } @Override public void onCompleted() { bsub.onCompleted(); } }; child.add(closingSubscriber); child.add(bsub); closing.unsafeSubscribe(closingSubscriber); return bsub; } final class BufferingSubscriber extends Subscriber { final Subscriber> child; /** Guarded by this. */ List chunk; /** Guarded by this. */ boolean done; public BufferingSubscriber(Subscriber> child) { this.child = child; this.chunk = new ArrayList(initialCapacity); } @Override public void onNext(T t) { synchronized (this) { if (done) { return; } chunk.add(t); } } @Override public void onError(Throwable e) { synchronized (this) { if (done) { return; } done = true; chunk = null; } child.onError(e); unsubscribe(); } @Override public void onCompleted() { try { List toEmit; synchronized (this) { if (done) { return; } done = true; toEmit = chunk; chunk = null; } child.onNext(toEmit); } catch (Throwable t) { Exceptions.throwOrReport(t, child); return; } child.onCompleted(); unsubscribe(); } void emit() { List toEmit; synchronized (this) { if (done) { return; } toEmit = chunk; chunk = new ArrayList(initialCapacity); } try { child.onNext(toEmit); } catch (Throwable t) { unsubscribe(); synchronized (this) { if (done) { return; } done = true; } Exceptions.throwOrReport(t, child); } } } }




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