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

Go to download
Show more of this group Show more artifacts with this name
Show all versions of javimmutable-collections Show documentation
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.
There is a newer version: 3.2.1
Show newest version
///###////////////////////////////////////////////////////////////////////////
//
// Burton Computer Corporation
// http://www.burton-computer.com
//
// Copyright (c) 2013, Burton Computer Corporation
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//     Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
//
//     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.
//
//     Neither the name of the Burton Computer Corporation nor the names
//     of its contributors may be used to endorse or promote products
//     derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package org.javimmutable.collections.list;

import org.javimmutable.collections.Cursor;
import org.javimmutable.collections.JImmutableList;
import org.javimmutable.collections.array.trie.EmptyTrieNode;
import org.javimmutable.collections.array.trie.TrieNode;
import org.javimmutable.collections.common.IteratorAdaptor;
import org.javimmutable.collections.common.ListAdaptor;
import org.javimmutable.collections.cursors.Cursors;
import org.javimmutable.collections.cursors.StandardCursor;

import java.util.Iterator;
import java.util.List;

/**
 * Implementation of PersistentIndexedList that uses a sparse array for its implementation.
 * Values are stored and traversed in the same order as they are added using add().
 * Performance is slower than PersistentLinkedList so if forward order and/or random
 * access are not required using that class may be a better option.
 *
 * @param 
 */
public class JImmutableArrayList
        implements JImmutableList
{
    private static final JImmutableArrayList EMPTY = new JImmutableArrayList();

    private final TrieNode values;
    private final int size;

    public JImmutableArrayList()
    {
        this(EmptyTrieNode.of(), 0);
    }

    private JImmutableArrayList(TrieNode values,
                                int size)
    {
        this.values = values;
        this.size = size;
    }

    @SuppressWarnings("unchecked")
    public static  JImmutableArrayList of()
    {
        return (JImmutableArrayList)EMPTY;
    }

    @Override
    public boolean isEmpty()
    {
        return size == 0;
    }

    @Override
    public JImmutableList assign(int index,
                                    T value)
    {
        if (index < 0 || index >= size) {
            throw new ArrayIndexOutOfBoundsException();
        }
        return new JImmutableArrayList(values.assign(index >>> 5, index & 0x1f, value), size);
    }

    @Override
    public JImmutableArrayList insert(T value)
    {
        final int index = size;
        return new JImmutableArrayList(values.assign(index >>> 5, index & 0x1f, value), index + 1);
    }

    @Override
    public JImmutableArrayList deleteLast()
    {
        if (size <= 0) {
            throw new ArrayIndexOutOfBoundsException();
        }
        final int index = size - 1;
        return new JImmutableArrayList(values.delete(index >>> 5, index & 0x1f), index);
    }

    @Override
    public int size()
    {
        return size;
    }

    @Override
    public T get(int index)
    {
        if (index < 0 || index >= size) {
            throw new ArrayIndexOutOfBoundsException();
        }
        return values.get(index >>> 5, index & 0x1f).getValue();
    }

    @Override
    public List getList()
    {
        return ListAdaptor.of(this);
    }

    @Override
    public Cursor cursor()
    {
        return StandardCursor.of(new CursorSource(0));
    }

    @Override
    public Iterator iterator()
    {
        return IteratorAdaptor.of(cursor());
    }

    @Override
    public boolean equals(Object o)
    {
        return o instanceof JImmutableList && Cursors.areEqual(cursor(), ((JImmutableList)o).cursor());
    }

    @Override
    public int hashCode()
    {
        return Cursors.computeHashCode(cursor());
    }

    @Override
    public String toString()
    {
        return Cursors.makeString(cursor());
    }

    private class CursorSource
            implements StandardCursor.Source
    {
        private int index = 0;

        private CursorSource(int index)
        {
            this.index = index;
        }

        @Override
        public boolean atEnd()
        {
            return index >= size;
        }

        @Override
        public T currentValue()
        {
            return get(index);
        }

        @Override
        public StandardCursor.Source advance()
        {
            return new CursorSource(index + 1);
        }
    }
}