EmptyComponent.java

/**
 * Copyright 2016 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 io.reactivex.internal.subscribers.flowable;

import org.reactivestreams.*;

import io.reactivex.Observer;
import io.reactivex.disposables.Disposable;
import io.reactivex.plugins.RxJavaPlugins;

/**
 * Singleton implementing many interfaces as empty.
 */
public enum EmptyComponent implements Subscriber<Object>, Observer<Object>, Subscription, Disposable {
    INSTANCE;

    @SuppressWarnings("unchecked")
    public static <T> Subscriber<T> asSubscriber() {
        return (Subscriber<T>)INSTANCE;
    }
    
    @SuppressWarnings("unchecked")
    public static <T> Observer<T> asObserver() {
        return (Observer<T>)INSTANCE;
    }
    
    @Override
    public void dispose() {
        // deliberately no-op
    }

    @Override
    public boolean isDisposed() {
        return true;
    }

    @Override
    public void request(long n) {
        // deliberately no-op
    }

    @Override
    public void cancel() {
        // deliberately no-op
    }

    @Override
    public void onSubscribe(Disposable d) {
        d.dispose();
    }

    @Override
    public void onSubscribe(Subscription s) {
        s.cancel();
    }

    @Override
    public void onNext(Object t) {
        // deliberately no-op
    }

    @Override
    public void onError(Throwable t) {
        RxJavaPlugins.onError(t);
    }

    @Override
    public void onComplete() {
        // deliberately no-op
    }
}