KeySortUtility.java

/*
 *   
 *
 * Copyright  1990-2009 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 only, as published by the Free Software Foundation.
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License version 2 for more details (a copy is
 * included at /legal/license.txt).
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions.
 */

package com.sun.j2me.pim;

import java.util.Vector;

/**
 * Class KeySortUtility contains static method "store" only.
 * @see store 
 *
 */
class KeySortUtility {
    
    /**
     * Support method. Maintains a list, valueList, where each element in
     * the list has a corresponding key (of type Long) stored in keyList.
     * This method inserts "value" into "valueList" with the following
     * postconditions:
     * <ul>
     * <li> keyList.size() == valueList.size()
     * <li> keyList[i] corresponds to valueList[i] (0 <= i < keyList.size())
     * <li> keyList is in ascending order of keys
     * <li> keyList contains key
     * <li> valueList contains value
     * <li> key corresponds to value
     * </ul>
     * The following are preconditions:
     * <ul>
     * <li> keyList.size() == valueList.size()
     * <li> keyList[i] corresponds to valueList[i] (0 <= i < keyList.size())
     * <li> keyList is in ascending order of keys
     * </ul>
     * In order to maintain the arrays correctly, the objects passed as keyList
     * and valueList should <i>only</i> be modified by this method.
     * <p>Preconditions are not verified by this method.
     * @param keyList array or property names
     * @param valueList array of property values
     * @param key identifier for this list
     * @param value target object to store the list
     */
    static void store(Vector keyList, Vector valueList, long key,
		      Object value) {
        // do a binary chop search for the index before which to
        // insert value
        int lowerBound = 0;
        int upperBound = keyList.size();
        while (lowerBound != upperBound) {
            int index = lowerBound + (upperBound - lowerBound) / 2;
            long indexKey =
                ((Long) keyList.elementAt(index)).longValue();
            if (indexKey > key) {
                if (index == upperBound) {
                    upperBound --;
                } else {
                    upperBound = index;
                }
            } else {
                if (index == lowerBound) {
                    lowerBound ++;
                } else {
                    lowerBound = index;
                }
            }
        }
        keyList.insertElementAt(new Long(key), lowerBound);
        valueList.insertElementAt(value, lowerBound);
    }
}