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 }