1 /* 2 * Copyright (c) 2012, 2013, 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 package java.util.stream; 26 27 import java.util.Iterator; 28 import java.util.Spliterator; 29 30 /** 31 * Base interface for stream types such as {@link Stream}, {@link IntStream}, 32 * etc. Contains methods common to all stream types. 33 * 34 * @param <T> type of stream elements 35 * @param <S> type of stream implementing {@code BaseStream} 36 * @since 1.8 37 */ 38 public interface BaseStream<T, S extends BaseStream<T, S>> { 39 /** 40 * Returns an iterator for the elements of this stream. 41 * 42 * <p>This is a <a href="package-summary.html#StreamOps">terminal 43 * operation</a>. 44 * 45 * @return the element iterator for this stream 46 */ 47 Iterator<T> iterator(); 48 49 /** 50 * Returns a spliterator for the elements of this stream. 51 * 52 * <p>This is a <a href="package-summary.html#StreamOps">terminal 53 * operation</a>. 54 * 55 * @return the element spliterator for this stream 56 */ 57 Spliterator<T> spliterator(); 58 59 /** 60 * Returns whether this stream, when executed, would execute in parallel 61 * (assuming no further modification of the stream, such as appending 62 * further intermediate operations or changing its parallelism). Calling 63 * this method after invoking an intermediate or terminal stream operation 64 * method may yield unpredictable results. 65 * 66 * @return {@code true} if this stream would execute in parallel if executed 67 * without further modification otherwise {@code false} 68 */ 69 boolean isParallel(); 70 71 /** 72 * Returns an equivalent stream that is sequential. May return 73 * itself, either because the stream was already sequential, or because 74 * the underlying stream state was modified to be sequential. 75 * 76 * <p>This is an <a href="package-summary.html#StreamOps">intermediate 77 * operation</a>. 78 * 79 * @return a sequential stream 80 */ 81 S sequential(); 82 83 /** 84 * Returns an equivalent stream that is parallel. May return 85 * itself, either because the stream was already parallel, or because 86 * the underlying stream state was modified to be parallel. 87 * 88 * <p>This is an <a href="package-summary.html#StreamOps">intermediate 89 * operation</a>. 90 * 91 * @return a parallel stream 92 */ 93 S parallel(); 94 95 /** 96 * Returns an equivalent stream that is 97 * <a href="package-summary.html#Ordering">unordered</a>. May return 98 * itself if the stream was already unordered. 99 * 100 * <p>This is an <a href="package-summary.html#StreamOps">intermediate 101 * operation</a>. 102 * 103 * @return an unordered stream 104 */ 105 S unordered(); 106 }