001/* 002 * ============================================================================ 003 * Copyright © 2014 by Dominic Fox. 004 * All Rights Reserved. 005 * ============================================================================ 006 * The MIT License (MIT) 007 * 008 * Permission is hereby granted, free of charge, to any person obtaining a copy 009 * of this software and associated documentation files (the "Software"), to 010 * deal in the Software without restriction, including without limitation the 011 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 012 * sell copies of the Software, and to permit persons to whom the Software is 013 * furnished to do so, subject to the following conditions: 014 * 015 * The above copyright notice and this permission notice shall be included in 016 * all copies or substantial portions of the Software. 017 * 018 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 019 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 020 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE 021 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 022 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 023 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 024 * IN THE SOFTWARE. 025 */ 026 027package org.tquadrat.foundation.stream.internal; 028 029import static org.apiguardian.api.API.Status.INTERNAL; 030import static org.tquadrat.foundation.lang.Objects.requireNonNullArgument; 031 032import java.util.Spliterator; 033import java.util.function.BiFunction; 034import java.util.function.Consumer; 035 036import org.apiguardian.api.API; 037import org.tquadrat.foundation.annotation.ClassVersion; 038 039/** 040 * An implementation of 041 * {@link Spliterator} 042 * that zips two streams into one. 043 * 044 * @author Dominic Fox 045 * @modified Thomas Thrien - thomas.thrien@tquadrat.org 046 * @version $Id: ZippingSpliterator.java 1060 2023-09-24 19:21:40Z tquadrat $ 047 * @since 0.0.7 048 * 049 * @param <L> The type over which the "left" stream is streaming. 050 * @param <R> The type over which the "right" stream is streaming. 051 * @param <O> The type created by the combiner out of pairs of 052 * "left" and "right" values, over which the resulting 053 * stream streams. 054 * 055 * @UMLGraph.link 056 */ 057@ClassVersion( sourceVersion = "$Id: ZippingSpliterator.java 1060 2023-09-24 19:21:40Z tquadrat $" ) 058@API( status = INTERNAL, since = "0.0.7" ) 059public final class ZippingSpliterator<L,R,O> implements Spliterator<O> 060{ 061 /*------------*\ 062 ====** Attributes **======================================================= 063 \*------------*/ 064 /** 065 * The combiner function. 066 */ 067 private final BiFunction<L,R,O> m_Combiner; 068 069 /** 070 * The left-hand source. 071 */ 072 private final Spliterator<L> m_Lefts; 073 074 /** 075 * Flag the indicates whether the right-hand source has the next value. 076 */ 077 private boolean m_RightHadNext = false; 078 079 /** 080 * The right-hand source. 081 */ 082 private final Spliterator<R> m_Rights; 083 084 /*--------------*\ 085 ====** Constructors **===================================================== 086 \*--------------*/ 087 /** 088 * Creates a new {@code ZippingSpliterator} instance. 089 * 090 * @param lefts The left-hand source. 091 * @param rights The right-hand source. 092 * @param combiner The combiner. 093 */ 094 private ZippingSpliterator( final Spliterator<L> lefts, final Spliterator<R> rights, final BiFunction<L,R,O> combiner ) 095 { 096 m_Lefts = requireNonNullArgument( lefts, "lefts" ); 097 m_Rights = requireNonNullArgument( rights, "rights" ); 098 m_Combiner = requireNonNullArgument( combiner, "combiner" ); 099 } // ZippingSpliterator() 100 101 /*---------*\ 102 ====** Methods **========================================================== 103 \*---------*/ 104 /** 105 * {@inheritDoc} 106 */ 107 @Override 108 public final int characteristics() 109 { 110 @SuppressWarnings( "ConstantExpression" ) 111 final var retValue = m_Lefts.characteristics() & m_Rights.characteristics() & ~ (DISTINCT | SORTED); 112 113 //---* Done *---------------------------------------------------------- 114 return retValue; 115 } // characteristics() 116 117 /** 118 * {@inheritDoc} 119 */ 120 @Override 121 public final long estimateSize() { return Math.min( m_Lefts.estimateSize(), m_Rights.estimateSize() ); } 122 123 /** 124 * {@inheritDoc} 125 */ 126 @Override 127 public final boolean tryAdvance( final Consumer<? super O> action ) 128 { 129 m_RightHadNext = false; 130 final var leftHadNext = m_Lefts.tryAdvance( left -> 131 m_Rights.tryAdvance( right -> { 132 m_RightHadNext = true; 133 action.accept( m_Combiner.apply( left, right ) ); 134 } ) ); 135 final var retValue = leftHadNext && m_RightHadNext; 136 137 //---* Done *---------------------------------------------------------- 138 return retValue; 139 } // tryAdvance() 140 141 /** 142 * {@inheritDoc} 143 */ 144 @Override 145 public final Spliterator<O> trySplit() { return null; } 146 147 /** 148 * Factory for instances of {@code ZippingSpliterator}. 149 * 150 * @param <L> The type over which the "left" stream is 151 * streaming. 152 * @param <R> The type over which the "right" stream is 153 * streaming. 154 * @param <O> The type created by the combiner out of pairs of 155 * "left" and "right" values, over which the 156 * resulting stream streams. 157 * @param lefts The left-hand source. 158 * @param rights The right-hand source. 159 * @param combiner The combiner. 160 * @return The new instance. 161 */ 162 public static final <L,R,O> Spliterator<O> zipping( final Spliterator<L> lefts, final Spliterator<R> rights, final BiFunction<L,R,O> combiner ) 163 { 164 final var retValue = new ZippingSpliterator<>( lefts, rights, combiner ); 165 166 //---* Done *---------------------------------------------------------- 167 return retValue; 168 } // zipping() 169} 170// class ZippingSpliterator 171 172/* 173 * End of File 174 */