Copyright (c) 2016-present, RxJava Contributors.
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.
/**
 * Copyright (c) 2016-present, RxJava Contributors.
 *
 * 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.disposables;

import java.util.concurrent.atomic.AtomicReference;

import io.reactivex.disposables.Disposable;

A Disposable container that allows updating/replacing a Disposable
atomically and with respect of disposing the container itself.

The class extends AtomicReference directly so watch out for the API leak!
Since:
2.0/**
 * A Disposable container that allows updating/replacing a Disposable
 * atomically and with respect of disposing the container itself.
 * <p>
 * The class extends AtomicReference directly so watch out for the API leak!
 * @since 2.0
 */
public final class SequentialDisposable
extends AtomicReference<Disposable>
implements Disposable {

    private static final long serialVersionUID = -754898800686245608L;

    
Constructs an empty SequentialDisposable.
/**
     * Constructs an empty SequentialDisposable.
     */
    public SequentialDisposable() {
        // nothing to do
    }

    
Construct a SequentialDisposable with the initial Disposable provided.
Params:
initial – the initial disposable, null allowed/**
     * Construct a SequentialDisposable with the initial Disposable provided.
     * @param initial the initial disposable, null allowed
     */
    public SequentialDisposable(Disposable initial) {
        lazySet(initial);
    }

    
Atomically: set the next disposable on this container and dispose the previous
one (if any) or dispose next if the container has been disposed.
Params:
next – the Disposable to set, may be null
See Also:
replace(Disposable)
Returns:
true if the operation succeeded, false if the container has been disposed/**
     * Atomically: set the next disposable on this container and dispose the previous
     * one (if any) or dispose next if the container has been disposed.
     * @param next the Disposable to set, may be null
     * @return true if the operation succeeded, false if the container has been disposed
     * @see #replace(Disposable)
     */
    public boolean update(Disposable next) {
        return DisposableHelper.set(this, next);
    }

    
Atomically: set the next disposable on this container but don't dispose the previous
one (if any) or dispose next if the container has been disposed.
Params:
next – the Disposable to set, may be null
See Also:
update(Disposable)
Returns:
true if the operation succeeded, false if the container has been disposed/**
     * Atomically: set the next disposable on this container but don't dispose the previous
     * one (if any) or dispose next if the container has been disposed.
     * @param next the Disposable to set, may be null
     * @return true if the operation succeeded, false if the container has been disposed
     * @see #update(Disposable)
     */
    public boolean replace(Disposable next) {
        return DisposableHelper.replace(this, next);
    }

    @Override
    public void dispose() {
        DisposableHelper.dispose(this);
    }

    @Override
    public boolean isDisposed() {
        return DisposableHelper.isDisposed(get());
    }
}