org.javimmutable.collections.hash.MultiHashValueListNode Maven / Gradle / Ivy

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// Burton Computer Corporation
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// Copyright (c) 2017, Burton Computer Corporation
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package org.javimmutable.collections.hash;

import org.javimmutable.collections.Cursor;
import org.javimmutable.collections.Holder;
import org.javimmutable.collections.Holders;
import org.javimmutable.collections.JImmutableMap;
import org.javimmutable.collections.Sequence;
import org.javimmutable.collections.SplitableIterator;
import org.javimmutable.collections.common.EmptySequence;
import org.javimmutable.collections.common.MutableDelta;
import org.javimmutable.collections.cursors.SequenceCursor;
import org.javimmutable.collections.iterators.SequenceIterator;

import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;

@Immutable
class MultiHashValueListNode
    implements HashValueListNode,
               Sequence>
{
    private final MultiHashValueListNode next;
    private final SingleHashValueListNode entry;

    private MultiHashValueListNode(MultiHashValueListNode next,
                                   SingleHashValueListNode entry)
    {
        this.next = next;
        this.entry = entry;
    }

    static  MultiHashValueListNode of(K key,
                                                  V value)
    {
        return new MultiHashValueListNode(null, SingleHashValueListNode.of(key, value));
    }

    static  MultiHashValueListNode of(SingleHashValueListNode entry1,
                                                  SingleHashValueListNode entry2)
    {
        return new MultiHashValueListNode(new MultiHashValueListNode(null, entry1), entry2);
    }

    static  MultiHashValueListNode of(SingleHashValueListNode entry1,
                                                  SingleHashValueListNode entry2,
                                                  SingleHashValueListNode entry3)
    {
        return new MultiHashValueListNode(new MultiHashValueListNode(new MultiHashValueListNode(null, entry1), entry2), entry3);
    }

    @Override
    public Holder getValueForKey(K key)
    {
        SingleHashValueListNode answer = getEntryForKeyImpl(key);
        if (answer != null) {
            return answer;
        } else {
            return Holders.of();
        }
    }

    @Override
    public JImmutableMap.Entry getEntryForKey(K key)
    {
        return getEntryForKeyImpl(key);
    }

    @Override
    public MultiHashValueListNode setValueForKey(K key,
                                                       V value,
                                                       MutableDelta sizeDelta)
    {
        SingleHashValueListNode entry = getEntryForKeyImpl(key);
        if (entry == null) {
            sizeDelta.add(1);
            return new MultiHashValueListNode(this, SingleHashValueListNode.of(key, value));
        } else if (entry.getValue() == value) {
            return this;
        } else {
            return new MultiHashValueListNode(removeKeyFromList(key), SingleHashValueListNode.of(key, value));
        }
    }

    @Override
    public HashValueListNode deleteValueForKey(K key,
                                                     MutableDelta sizeDelta)
    {
        if (getEntryForKey(key) == null) {
            return this;
        }
        MultiHashValueListNode newList = removeKeyFromList(key);
        sizeDelta.subtract(1);
        return (newList != null && newList.next == null) ? newList.entry : newList;
    }

    @Override
    public boolean isEmpty()
    {
        return false;
    }

    @Override
    public JImmutableMap.Entry getHead()
    {
        return entry;
    }

    @Nonnull
    @Override
    public Sequence> getTail()
    {
        if (next == null) {
            return EmptySequence.of();
        } else {
            return next;
        }
    }

    @Override
    @Nonnull
    public Cursor> cursor()
    {
        return SequenceCursor.of(this);
    }

    @Nonnull
    @Override
    public SplitableIterator> iterator()
    {
        return SequenceIterator.iterator(this);
    }

    @Override
    public boolean equals(Object o)
    {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        MultiHashValueListNode that = (MultiHashValueListNode)o;

        if (entry != null ? !entry.equals(that.entry) : that.entry != null) {
            return false;
        }
        //noinspection RedundantIfStatement
        if (next != null ? !next.equals(that.next) : that.next != null) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode()
    {
        int result = next != null ? next.hashCode() : 0;
        result = 31 * result + (entry != null ? entry.hashCode() : 0);
        return result;
    }

    @Override
    public String toString()
    {
        return "MultiValueLeafNode{" +
               "next=" + next +
               ", entry=" + entry +
               '}';
    }

    private MultiHashValueListNode removeKeyFromList(K key)
    {
        MultiHashValueListNode newList = null;
        for (MultiHashValueListNode node = this; node != null; node = node.next) {
            if (!node.keyEquals(key)) {
                newList = new MultiHashValueListNode(newList, node.entry);
            }
        }
        return newList;
    }

    private SingleHashValueListNode getEntryForKeyImpl(K key)
    {
        for (MultiHashValueListNode node = this; node != null; node = node.next) {
            if (node.keyEquals(key)) {
                return node.entry;
            }
        }
        return null;
    }

    private boolean keyEquals(K key)
    {
        return key.equals(entry.getKey());
    }
}