StringSorter.java

package ij.util;

public class StringSorter {
    
    public static void sort(String[] a) {
        if (!alreadySorted(a))
            sort(a, 0, a.length - 1);
    }
    
    static void sort(String[] a, int from, int to) {
        int i = from, j = to;
        String center = a[ (from + to) / 2 ];
        do {
            while ( i < to && center.compareTo(a[i]) > 0 ) i++;
            while ( j > from && center.compareTo(a[j]) < 0 ) j--;
            if (i < j) {String temp = a[i]; a[i] = a[j]; a[j] = temp; }
            if (i <= j) { i++; j--; }
        } while(i <= j);
        if (from < j) sort(a, from, j);
        if (i < to) sort(a,  i, to);
    }
        
    static boolean alreadySorted(String[] a) {
        for ( int i=1; i<a.length; i++ ) {
            if (a[i].compareTo(a[i-1]) < 0 )
            return false;
        }
        return true;
    }
}