org.javimmutable.collections.tree.EmptyNode Maven / Gradle / Ivy

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//
// Burton Computer Corporation
// http://www.burton-computer.com
//
// Copyright (c) 2018, Burton Computer Corporation
// All rights reserved.
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package org.javimmutable.collections.tree;

import org.javimmutable.collections.Cursor;
import org.javimmutable.collections.Func1;
import org.javimmutable.collections.Holder;
import org.javimmutable.collections.Holders;
import org.javimmutable.collections.JImmutableMap;
import org.javimmutable.collections.SplitableIterator;
import org.javimmutable.collections.Tuple2;
import org.javimmutable.collections.cursors.StandardCursor;
import org.javimmutable.collections.iterators.EmptyIterator;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;
import java.util.Comparator;

@Immutable
public class EmptyNode
    implements Node
{
    @SuppressWarnings("unchecked")
    static final EmptyNode INSTANCE = new EmptyNode();

    @SuppressWarnings("unchecked")
    public static  Node of()
    {
        return INSTANCE;
    }

    @Nullable
    @Override
    public K baseKey()
    {
        throw new UnsupportedOperationException();
    }

    @Override
    public int childCount()
    {
        return 0;
    }

    @Override
    public int valueCount()
    {
        return 0;
    }

    @Override
    public V getValueOr(@Nonnull Comparator comparator,
                        @Nonnull K key,
                        V defaultValue)
    {
        return defaultValue;
    }

    @Nonnull
    @Override
    public Holder find(@Nonnull Comparator comparator,
                          @Nonnull K key)
    {
        return Holders.of();
    }

    @Nonnull
    @Override
    public Holder> findEntry(@Nonnull Comparator comparator,
                                                       @Nonnull K key)
    {
        return Holders.of();
    }

    @Nonnull
    @Override
    public UpdateResult assign(@Nonnull Comparator comparator,
                                     @Nonnull K key,
                                     V value)
    {
        return UpdateResult.createInPlace(new LeafNode<>(key, value), 1);
    }

    @Nonnull
    @Override
    public UpdateResult update(@Nonnull Comparator comparator,
                                     @Nonnull K key,
                                     @Nonnull Func1, V> generator)
    {
        return UpdateResult.createInPlace(new LeafNode<>(key, generator.apply(Holders.of())), 1);
    }

    @Nonnull
    @Override
    public Node delete(@Nonnull Comparator comparator,
                             @Nonnull K key)
    {
        return this;
    }

    @Nonnull
    @Override
    public Node mergeChildren(@Nonnull Node sibling)
    {
        return sibling;
    }

    @Nonnull
    @Override
    public Tuple2, Node> distributeChildren(@Nonnull Node sibling)
    {
        throw new UnsupportedOperationException();
    }

    @Nonnull
    @Override
    public Node compress()
    {
        return this;
    }

    @Override
    public int depth()
    {
        return 0;
    }

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

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

    @Nonnull
    @Override
    public SplitableIterator> iterator()
    {
        return EmptyIterator.of();
    }

    @Override
    public void checkInvariants(@Nonnull Comparator comparator)
    {
    }
}