org.eclipse.jetty.util.CountingCallback Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of aem-sdk-api Show documentation

The Adobe Experience Manager SDK

There is a newer version: 2024.11.18751.20241128T090041Z-241100

// 
// ========================================================================
// Copyright (c) 1995-2022 Mort Bay Consulting Pty Ltd and others.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
// 
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
// 
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
// 
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
// 
package org.eclipse.jetty.util;

import java.util.concurrent.atomic.AtomicInteger;

/**
 *  A callback wrapper that succeeds the wrapped callback when the count is
 *  reached, or on first failure.
 *  This callback is particularly useful when an async operation is split
 *  into multiple parts, for example when an original byte buffer that needs
 *  to be written, along with a callback, is split into multiple byte buffers,
 *  since it allows the original callback to be wrapped and notified only when
 *  the last part has been processed.
 *  Example:
 *   *  public void process(EndPoint endPoint, ByteBuffer buffer, Callback callback)
 *  {
 *      ByteBuffer[] buffers = split(buffer);
 *      CountCallback countCallback = new CountCallback(callback, buffers.length);
 *      endPoint.write(countCallback, buffers);
 *  }
 *  
 *
 * @deprecated The Eclipse Jetty and Apache Felix Http Jetty packages are no longer supported.
 */
@Deprecated(since = "2021-05-27")
public class CountingCallback extends Callback.Nested {

    private final AtomicInteger count;

    public CountingCallback(Callback callback, int count) {
        super(callback);
        if (count < 1)
            throw new IllegalArgumentException();
        this.count = new AtomicInteger(count);
    }

    @Override
    public void succeeded() {
        // Forward success on the last success.
        while (true) {
            int current = count.get();
            // Already completed ?
            if (current == 0)
                return;
            if (count.compareAndSet(current, current - 1)) {
                if (current == 1)
                    super.succeeded();
                return;
            }
        }
    }

    @Override
    public void failed(Throwable failure) {
        // Forward failure on the first failure.
        while (true) {
            int current = count.get();
            // Already completed ?
            if (current == 0)
                return;
            if (count.compareAndSet(current, 0)) {
                super.failed(failure);
                return;
            }
        }
    }

    @Override
    public String toString() {
        return String.format("%s@%x", getClass().getSimpleName(), hashCode());
    }
}