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Library providing immutable/persistent collection classes for Java. While collections are immutable they provide methods for adding and removing values by creating new modified copies of themselves. Each copy shares almost all of its structure with other copies to minimize memory consumption.
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///###////////////////////////////////////////////////////////////////////////
//
// Burton Computer Corporation
// http://www.burton-computer.com
//
// Copyright (c) 2017, Burton Computer Corporation
// All rights reserved.
//
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//
//     Redistributions in binary form must reproduce the above copyright
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package org.javimmutable.collections.list;

import org.javimmutable.collections.Cursor;
import org.javimmutable.collections.Indexed;
import org.javimmutable.collections.common.IndexedArray;
import org.javimmutable.collections.common.IndexedList;
import org.javimmutable.collections.cursors.StandardCursor;

import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;
import java.util.List;

/**
 * Node that forms the bottom of the 32-way tree and contains up to 32 values.
 *
 * @param 
 */
@Immutable
class LeafNode
        implements Node
{
    @Nonnull
    private final T[] values;

    private LeafNode(@Nonnull T[] values)
    {
        assert values.length > 0;
        assert values.length <= 32;
        this.values = values;
    }

    LeafNode(T value)
    {
        values = ListHelper.allocateValues(1);
        values[0] = value;
    }

    static  LeafNode fromList(List values,
                                    int offset,
                                    int limit)
    {
        return fromList(IndexedList.retained(values), offset, limit);
    }

    static  LeafNode fromList(Indexed values,
                                    int offset,
                                    int limit)
    {
        T[] array = ListHelper.allocateValues(limit - offset);
        for (int i = offset; i < limit; ++i) {
            array[i - offset] = values.get(i);
        }
        return new LeafNode(array);
    }

    static  LeafNode forTesting(T[] values)
    {
        return new LeafNode(values.clone());
    }

    @Override
    public boolean isEmpty()
    {
        return values.length == 0;
    }

    @Override
    public boolean isFull()
    {
        return values.length == 32;
    }

    @Override
    public int size()
    {
        return values.length;
    }

    @Override
    public int getDepth()
    {
        return 1;
    }

    @Override
    public Node deleteFirst()
    {
        if (values.length == 1) {
            return EmptyNode.of();
        }
        T[] newValues = ListHelper.allocateValues(values.length - 1);
        System.arraycopy(values, 1, newValues, 0, newValues.length);
        return new LeafNode(newValues);
    }

    @Override
    public Node deleteLast()
    {
        if (values.length == 1) {
            return EmptyNode.of();
        }
        T[] newValues = ListHelper.allocateValues(values.length - 1);
        System.arraycopy(values, 0, newValues, 0, newValues.length);
        return new LeafNode(newValues);
    }

    @Override
    public Node insertFirst(T value)
    {
        if (isFull()) {
            return new BranchNode(value, this);
        }
        T[] newValues = ListHelper.allocateValues(values.length + 1);
        System.arraycopy(values, 0, newValues, 1, values.length);
        newValues[0] = value;
        return new LeafNode(newValues);
    }

    @Override
    public Node insertLast(T value)
    {
        if (isFull()) {
            return new BranchNode(this, value);
        }
        T[] newValues = ListHelper.allocateValues(values.length + 1);
        System.arraycopy(values, 0, newValues, 0, values.length);
        newValues[values.length] = value;
        return new LeafNode(newValues);
    }

    @Override
    public boolean containsIndex(int index)
    {
        return (index >= 0) && (index < values.length);
    }

    @Override
    public T get(int index)
    {
        return values[index];
    }

    @Override
    public Node assign(int index,
                          T value)
    {
        T[] newValues = values.clone();
        newValues[index] = value;
        return new LeafNode(newValues);
    }

    @Nonnull
    @Override
    public Cursor cursor()
    {
        return StandardCursor.of(IndexedArray.retained(values));
    }

    @Override
    public void checkInvariants()
    {
        if ((values.length == 0) || (values.length > 32)) {
            throw new IllegalStateException();
        }
        //TODO: review checkInvariants()
    }
}