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

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// Burton Computer Corporation
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package org.javimmutable.collections.tree;

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

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

@Immutable
public class EmptyNode
    extends TreeNode
{
    static final EmptyNode INSTANCE = new EmptyNode();

    private EmptyNode()
    {
    }

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

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

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

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

    @Override
    public void addEntriesTo(Collection> collection)
    {
    }

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

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

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

    @Override
    int verifyDepthsMatch()
    {
        return 0;
    }

    @Override
    K getMaxKey()
    {
        return null;
    }

    @Override
    UpdateResult assignImpl(Comparator props,
                                  K key,
                                  V value)
    {
        return UpdateResult.createInPlace(new LeafNode(key, value), 1);
    }

    @Override
    DeleteResult deleteImpl(Comparator props,
                                  K key)
    {
        return DeleteResult.createUnchanged();
    }

    @Override
    DeleteMergeResult leftDeleteMerge(TreeNode node)
    {
        throw new UnsupportedOperationException();
    }

    @Override
    DeleteMergeResult rightDeleteMerge(TreeNode node)
    {
        throw new UnsupportedOperationException();
    }
}