/** * 雙向氣泡排序算法 */class BidirBubbleSortAlgorithm extends SortAlgorithm {    void sort(int a[]) throws Exception {	int j;	int limit = a.length;	int st = -1;	while (st < limit) {	    st++;	    limit--;	    boolean swapped = false;	    for (j = st; j < limit; j++) {		if (stopRequested) {		    return;		}		if (a[j] > a[j + 1]) {		    int T = a[j];		    a[j] = a[j + 1];		    a[j + 1] = T;		    swapped = true;		}		pause(st, limit);	    }	    if (!swapped) {		return;	    }	    else		swapped = false;	    for (j = limit; --j >= st;) {		if (stopRequested) {		    return;		}		if (a[j] > a[j + 1]) {		    int T = a[j];		    a[j] = a[j + 1];		    a[j + 1] = T;		    swapped = true;		}		pause(st, limit);	    }	    if (!swapped) {		return;	    }	}    }}