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

import org.javimmutable.collections.Indexed;

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

@Immutable
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();
    }
}