/* Copyright (c) 2002-2011 by XMLVM.org
*
* Project Info: http://www.xmlvm.org
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*/
package org.xmlvm.util.comparators;
import java.util.Comparator;
/**
* Sort Java classes first by priority packages: "java.*", "org.apache.*" and
* "org.xmlvm.*", then by full name. This is often done to sort core/priority
* classes first, granting them lower indices in a sorted list. This is more
* ideal because core libraries are less likely to change. So if a change is
* made to a class that is not in the core library, then the beginning of the
* list, which contains the core library, will remain unchanged.
*/
public class ClassNameComparator implements Comparator<String>
{
private static String[] PRIORITY_PREFIXES= new String[] { "java.", "org.apache.", "org.xmlvm." };
/**
* Compare two class names including their package name with certain
* packages being given priority. This is not an alphabetic comparator.
*
* @param fullClassName1
* the first full class name
* @param fullClassName2
* the second full class name
* @return a negative integer, zero, or a positive integer as the first
* class name has a higher, equal, or lower priority than the second
* class name
*/
public int compare(String fullClassName1, String fullClassName2)
{
int result= 0;
int c1= getFirstCompareValue(fullClassName1);
int c2= getFirstCompareValue(fullClassName2);
result= c1 - c2;
if (result == 0)
{
result= fullClassName1.compareTo(fullClassName2);
}
return result;
}
/**
* Determine priority of the name by comparing it to special prefixes
* @param fullName the full name of the class including package name
* @return a priority number based on priority prefixes
*/
private static int getFirstCompareValue(String fullName)
{
int c= Integer.MAX_VALUE;
int i= 0;
while (i < PRIORITY_PREFIXES.length && c > i)
{
if (fullName.startsWith(PRIORITY_PREFIXES[i++]))
{
c= i;
}
}
return c;
}
}