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 org.apiguardian.api.API;
030import org.tquadrat.foundation.annotation.ClassVersion;
031
032import java.util.Spliterator;
033import java.util.function.Consumer;
034import java.util.function.Predicate;
035
036import static org.apiguardian.api.API.Status.INTERNAL;
037import static org.tquadrat.foundation.lang.Objects.requireNonNullArgument;
038
039/**
040 *  An implementation of
041 *  {@link Spliterator}
042 *  that takes elements from a stream while the given
043 *  {@link Predicate Predicate}
044 *  returns {@code true}.
045 *
046 *  @author Dominic Fox
047 *  @modified Thomas Thrien - thomas.thrien@tquadrat.org
048 *  @version $Id: TakeWhileSpliterator.java 1119 2024-03-16 09:03:57Z tquadrat $
049 *  @since 0.0.7
050 *
051 *  @param  <T> The type of the stream elements.
052 *
053 *  @UMLGraph.link
054 */
055@ClassVersion( sourceVersion = "$Id: TakeWhileSpliterator.java 1119 2024-03-16 09:03:57Z tquadrat $" )
056@API( status = INTERNAL, since = "0.0.7" )
057public final class TakeWhileSpliterator<T> implements Spliterator<T>
058{
059        /*------------*\
060    ====** Attributes **=======================================================
061        \*------------*/
062    /**
063     *  The condition for the spliterator.
064     */
065    private final Predicate<T> m_Condition;
066
067    /**
068     *  Flag that indicates whether the condition still returns {@code true}.
069     */
070    private boolean m_ConditionHolds = true;
071
072    /**
073     *  The source.
074     */
075    private final Spliterator<T> m_Source;
076
077        /*--------------*\
078    ====** Constructors **=====================================================
079        \*--------------*/
080    /**
081     *  Creates a new {@code TakeWhileSpliterator} instance.
082     *
083     *  @param  source  The source.
084     *  @param  condition   The condition for the new instance.
085     */
086    private TakeWhileSpliterator( final Spliterator<T> source, final Predicate<T> condition )
087    {
088        m_Source = requireNonNullArgument( source, "source" );
089        m_Condition = requireNonNullArgument( condition, "condition" );
090    }   //  TakeWhileSpliterator()
091
092        /*---------*\
093    ====** Methods **==========================================================
094        \*---------*/
095    /**
096     *  {@inheritDoc}
097     */
098    @Override
099    public final int characteristics()
100    {
101        @SuppressWarnings( "ConstantExpression" )
102        final var retValue = m_Source.characteristics() & ~SIZED;
103
104        //---* Done *----------------------------------------------------------
105        return retValue;
106    }   //  characteristics()
107
108    /**
109     *  {@inheritDoc}
110     */
111    @Override
112    public final long estimateSize() { return m_ConditionHolds ? m_Source.estimateSize() : 0; }
113
114    /**
115     *  Factory method for instances of {@code TakeWhileSpliterator}.
116     *
117     *  @param  <T> The type of the stream elements.
118     *  @param  source  The source.
119     *  @param  condition   The condition for the new instance.
120     *  @return The new instance.
121     */
122    public static final <T> TakeWhileSpliterator<T> over( final Spliterator<T> source, final Predicate<T> condition )
123    {
124        final var retValue = new TakeWhileSpliterator<>( source, condition );
125
126        //---* Done *----------------------------------------------------------
127        return retValue;
128    }   //  over()
129
130    /**
131     *  {@inheritDoc}
132     */
133    @Override
134    public final boolean tryAdvance( final Consumer<? super T> action )
135    {
136        final var retValue = m_ConditionHolds
137            && m_Source.tryAdvance( e ->
138            {
139                //noinspection NestedAssignment,PointlessBooleanExpression
140                if( (m_ConditionHolds = m_Condition.test( e )) == true )
141                {
142                    action.accept( e );
143                }
144            });
145
146        //---* Done *----------------------------------------------------------
147        return retValue;
148    }   //  tryAdvance()
149
150    /**
151     *  {@inheritDoc}
152     */
153    @Override
154    public final Spliterator<T> trySplit(){ return null; }
155}
156//  class TakeWhileSpliterator
157
158/*
159 *  End of File
160 */