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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
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// Copyright (c) 2013, Burton Computer Corporation
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package org.javimmutable.collections.common;

import org.javimmutable.collections.Indexed;

import java.util.ArrayList;
import java.util.List;

public class IndexedList
        implements Indexed
{
    private final List values;

    private IndexedList(List values)
    {
        this.values = values;
    }

    /**
     * Produces an instance using a copy of the specified List to ensure that changes to the List
     * will not influence the values returned by the instance's methods.  This is generally preferred
     * to the unsafe() constructor.
     *
     * @param values
     * @param 
     * @return
     */
    public static  IndexedList copied(List values)
    {
        return new IndexedList(new ArrayList(values));
    }

    /**
     * Produces an instance using the provided List.  This makes the instance unsafe for sharing since
     * changes to the List will cause changes to this instance's values.  However this can be useful
     * when performance is important and the instance will not be shared or retained beyond a single
     * method scope.
     *
     * @param values
     * @param 
     * @return
     */
    public static  IndexedList retained(List values)
    {
        return new IndexedList(values);
    }

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

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