1 /* 2 * Copyright (c) 2016, 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.Iterator; 29 import java.util.concurrent.Flow; 30 31 /** 32 * A Publisher that is expected to run in same thread as subscriber. 33 * Items are obtained from Iterable. Each new subscription gets a new Iterator. 34 */ 35 class PullPublisher<T> implements Flow.Publisher<T> { 36 37 private final Iterable<T> iterable; 38 39 PullPublisher(Iterable<T> iterable) { 40 this.iterable = iterable; 41 } 42 43 @Override 44 public void subscribe(Flow.Subscriber<? super T> subscriber) { 45 subscriber.onSubscribe(new Subscription(subscriber, iterable.iterator())); 46 } 47 48 private class Subscription implements Flow.Subscription { 49 50 private final Flow.Subscriber<? super T> subscriber; 51 private final Iterator<T> iter; 52 private boolean done = false; 53 private long demand = 0; 54 private int recursion = 0; 55 56 Subscription(Flow.Subscriber<? super T> subscriber, Iterator<T> iter) { 57 this.subscriber = subscriber; 58 this.iter = iter; 59 } 60 61 @Override 62 public void request(long n) { 63 if (done) { 64 subscriber.onError(new IllegalArgumentException("request(" + n + ")")); 65 } 66 demand += n; 67 recursion ++; 68 if (recursion > 1) { 69 return; 70 } 71 while (demand > 0) { 72 done = !iter.hasNext(); 73 if (done) { 74 subscriber.onComplete(); 75 recursion --; 76 return; 77 } 78 subscriber.onNext(iter.next()); 79 demand --; 80 } 81 } 82 83 @Override 84 public void cancel() { 85 done = true; 86 } 87 88 } 89 } | 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.Iterator; 29 import java.util.concurrent.Flow; 30 import jdk.incubator.http.internal.common.Demand; 31 import jdk.incubator.http.internal.common.SequentialScheduler; 32 33 /** 34 * A Publisher that publishes items obtained from the given Iterable. Each new 35 * subscription gets a new Iterator. 36 */ 37 class PullPublisher<T> implements Flow.Publisher<T> { 38 39 // Only one of `iterable` and `throwable` can be non-null. throwable is 40 // non-null when an error has been encountered, by the creator of 41 // PullPublisher, while subscribing the subscriber, but before subscribe has 42 // completed. 43 private final Iterable<T> iterable; 44 private final Throwable throwable; 45 46 PullPublisher(Iterable<T> iterable, Throwable throwable) { 47 this.iterable = iterable; 48 this.throwable = throwable; 49 } 50 51 PullPublisher(Iterable<T> iterable) { 52 this(iterable, null); 53 } 54 55 @Override 56 public void subscribe(Flow.Subscriber<? super T> subscriber) { 57 Subscription sub; 58 if (throwable != null) { 59 assert iterable == null : "non-null iterable: " + iterable; 60 sub = new Subscription(subscriber, null, throwable); 61 } else { 62 assert throwable == null : "non-null exception: " + throwable; 63 sub = new Subscription(subscriber, iterable.iterator(), null); 64 } 65 subscriber.onSubscribe(sub); 66 67 if (throwable != null) { 68 sub.pullScheduler.runOrSchedule(); 69 } 70 } 71 72 private class Subscription implements Flow.Subscription { 73 74 private final Flow.Subscriber<? super T> subscriber; 75 private final Iterator<T> iter; 76 private volatile boolean completed; 77 private volatile boolean cancelled; 78 private volatile Throwable error; 79 final SequentialScheduler pullScheduler = new SequentialScheduler(new PullTask()); 80 private final Demand demand = new Demand(); 81 82 Subscription(Flow.Subscriber<? super T> subscriber, 83 Iterator<T> iter, 84 Throwable throwable) { 85 this.subscriber = subscriber; 86 this.iter = iter; 87 this.error = throwable; 88 } 89 90 final class PullTask extends SequentialScheduler.CompleteRestartableTask { 91 @Override 92 protected void run() { 93 if (completed || cancelled) { 94 return; 95 } 96 97 Throwable t = error; 98 if (t != null) { 99 completed = true; 100 pullScheduler.stop(); 101 subscriber.onError(t); 102 return; 103 } 104 105 while (demand.tryDecrement() && !cancelled) { 106 if (!iter.hasNext()) { 107 break; 108 } else { 109 subscriber.onNext(iter.next()); 110 } 111 } 112 if (!iter.hasNext() && !cancelled) { 113 completed = true; 114 pullScheduler.stop(); 115 subscriber.onComplete(); 116 } 117 } 118 } 119 120 @Override 121 public void request(long n) { 122 if (cancelled) 123 return; // no-op 124 125 if (n <= 0) { 126 error = new IllegalArgumentException("illegal non-positive request:" + n); 127 } else { 128 demand.increase(n); 129 } 130 pullScheduler.runOrSchedule(); 131 } 132 133 @Override 134 public void cancel() { 135 cancelled = true; 136 } 137 } 138 } |