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

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///###////////////////////////////////////////////////////////////////////////
//
// Burton Computer Corporation
// http://www.burton-computer.com
//
// Copyright (c) 2019, Burton Computer Corporation
// All rights reserved.
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//
//     Redistributions of source code must retain the above copyright
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//
//     Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in
//     the documentation and/or other materials provided with the
//     distribution.
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//     of its contributors may be used to endorse or promote products
//     derived from this software without specific prior written permission.
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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package org.javimmutable.collections.list;

import org.javimmutable.collections.Func2;
import org.javimmutable.collections.Proc1Throws;
import org.javimmutable.collections.Sum1Throws;
import org.javimmutable.collections.common.ToStringHelper;
import org.javimmutable.collections.iterators.GenericIterator;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;
import java.util.function.Consumer;

@Immutable
class EmptyNode
    extends AbstractNode
{
    private static EmptyNode INSTANCE = new EmptyNode();

    private EmptyNode()
    {
    }

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

    @Override
    boolean isEmpty()
    {
        return true;
    }

    @Override
    int size()
    {
        return 0;
    }

    @Override
    int depth()
    {
        return 0;
    }

    @Override
    T get(int index)
    {
        throw new IndexOutOfBoundsException();
    }

    @Nonnull
    @Override
    AbstractNode append(T value)
    {
        return new OneValueNode<>(value);
    }

    @Nonnull
    @Override
    AbstractNode append(@Nonnull AbstractNode node)
    {
        return node;
    }

    @Nonnull
    @Override
    AbstractNode prepend(T value)
    {
        return new OneValueNode<>(value);
    }

    @Nonnull
    @Override
    AbstractNode prepend(@Nonnull AbstractNode node)
    {
        return node;
    }

    @Nonnull
    @Override
    AbstractNode assign(int index,
                           T value)
    {
        throw new IndexOutOfBoundsException();
    }

    @Nonnull
    @Override
    AbstractNode insert(int index,
                           T value)
    {
        if (index == 0) {
            return new OneValueNode<>(value);
        } else {
            throw new IndexOutOfBoundsException();
        }
    }

    @Nonnull
    @Override
    AbstractNode delete(int index)
    {
        throw new IndexOutOfBoundsException();
    }

    @Nonnull
    @Override
    AbstractNode deleteFirst()
    {
        throw new IndexOutOfBoundsException();
    }

    @Nonnull
    @Override
    AbstractNode deleteLast()
    {
        throw new IndexOutOfBoundsException();
    }

    @Nonnull
    @Override
    AbstractNode prefix(int limit)
    {
        if (limit == 0) {
            return this;
        } else {
            throw new IndexOutOfBoundsException();
        }
    }

    @Override
    void copyTo(T[] array,
                int offset)
    {
    }

    @Nonnull
    @Override
    AbstractNode suffix(int offset)
    {
        if (offset == 0) {
            return this;
        } else {
            throw new IndexOutOfBoundsException();
        }
    }

    @Nonnull
    @Override
    AbstractNode reverse()
    {
        return this;
    }

    @Nullable
    @Override
    public GenericIterator.State iterateOverRange(@Nullable GenericIterator.State parent,
                                                     int offset,
                                                     int limit)
    {
        assert offset == 0 && limit == 0;
        return parent;
    }

    @Override
    public void forEach(Consumer action)
    {
    }

    @Override
    public  void forEachThrows(@Nonnull Proc1Throws proc)
        throws E
    {
    }

    @Override
    public  V reduce(V initialValue,
                        Func2 accumulator)
    {
        return initialValue;
    }

    @Override
    public  V reduceThrows(V initialValue,
                                                   Sum1Throws accumulator)
        throws E
    {
        return initialValue;
    }

    @Override
    public void checkInvariants()
    {
    }

    @Override
    public String toString()
    {
        final StringBuilder sb = new StringBuilder();
        sb.append("[");
        forEach(value -> ToStringHelper.addToString(sb, 1, value));
        sb.append("]");
        return sb.toString();
    }
}