1 /*

     2  * Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package jdk.incubator.http;

    27 

    28 import java.util.concurrent.Flow;

    29 import java.util.concurrent.atomic.AtomicBoolean;

    30 

    31 // Completes the subscription on first request. Never calls onNext()

    32 

    33 class PseudoPublisher<T> implements Flow.Publisher<T> {

    34 

    35     private final Throwable throwable;

    36 

    37     PseudoPublisher() {

    38         this(null);

    39     }

    40 

    41     PseudoPublisher(Throwable throwable) {

    42         this.throwable = throwable;

    43     }

    44 

    45     @Override

    46     public void subscribe(Flow.Subscriber<? super T> subscriber) {

    47         subscriber.onSubscribe(new Subscription(subscriber));

    48     }

    49 

    50     private class Subscription implements Flow.Subscription {

    51 

    52         private final Flow.Subscriber<? super T> subscriber;

    53         private final AtomicBoolean done = new AtomicBoolean();

    54 

    55         Subscription(Flow.Subscriber<? super T> subscriber) {

    56             this.subscriber = subscriber;

    57         }

    58 

    59         @Override

    60         public void request(long n) {

    61             if (done.compareAndSet(false, true)) {

    62                 if (n > 0) {

    63                     if (throwable == null) {

    64                         subscriber.onComplete();

    65                     } else {

    66                         subscriber.onError(throwable);

    67                     }

    68                 } else {

    69                     subscriber.onError(new IllegalArgumentException("request(" + n + ")"));

    70                 }

    71             }

    72         }

    73 

    74         @Override

    75         public void cancel() {

    76             done.set(true);

    77         }

    78 

    79     }

    80 }