/*
 * Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0, which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.glassfish.pfl.basic.contain ;

import java.util.ArrayList ;

Utility for managing mappings from densely allocated integer
keys to arbitrary objects.  This should only be used for
keys in the range 0..max such that "most" of the key space is actually
used.
/** Utility for managing mappings from densely allocated integer
 * keys to arbitrary objects.  This should only be used for
 * keys in the range 0..max such that "most" of the key space is actually
 * used.
 */
public class DenseIntMapImpl<E> implements IntMap<E>
{
    private ArrayList<E> list = new ArrayList<E>() ;

    private void checkKey( int key ) 
    {
	if (key < 0)
	    throw new IllegalArgumentException( "Key must be >= 0." ) ;
    }

    
If key >= 0, return the value bound to key, or null if none.
Throws IllegalArgumentException if key <0.
/** If key >= 0, return the value bound to key, or null if none.
     * Throws IllegalArgumentException if key <0.
     */
    public E get( int key ) 
    {
	checkKey( key ) ;

	E result = null ;
	if (key < list.size())
	    result = list.get( key ) ;

	return result ;
    }

    
If key >= 0, bind value to the key.
Throws IllegalArgumentException if key <0.
/** If key >= 0, bind value to the key.
     * Throws IllegalArgumentException if key <0.
     */
    public void set( int key, E value ) 
    {
	checkKey( key ) ;
	extend( key ) ;
	list.set( key, value ) ;
    }

    private void extend( int index )
    {
	if (index >= list.size()) {
	    list.ensureCapacity( index + 1 ) ;
	    int max = list.size() ;
	    while (max++ <= index)
		list.add( null ) ;
	}
    }
}