rx.internal.operators.OperatorSampleWithObservable Maven / Gradle / Ivy

/**
 * 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.concurrent.atomic.AtomicReference;
import rx.Observable;
import rx.Observable.Operator;
import rx.Subscriber;
import rx.observers.SerializedSubscriber;

/**
 * Sample with the help of another observable.
 * 
 * @see MSDN: Observable.Sample
 * 
 * @param  the source and result value type
 * @param  the element type of the sampler Observable
 */
public final class OperatorSampleWithObservable implements Operator {
    final Observable sampler;
    /** Indicates that no value is available. */
    static final Object EMPTY_TOKEN = new Object();

    public OperatorSampleWithObservable(Observable sampler) {
        this.sampler = sampler;
    }

    @Override
    public Subscriber call(Subscriber child) {
        final SerializedSubscriber s = new SerializedSubscriber(child);
    
        final AtomicReference