+ public class BindingGroup {
+ private HashSet<E> ess = new HashSet<E>();
+ public BindingGroup() { }
+ public BindingGroup(E e) {
+ ess.add(e);
+ }
+ public void add(E e) {
+ if (e.bg != null) { merge(e.bg); return; }
+ ess.add(e);
+ e.bg = this;
+ }
+ public void merge(BindingGroup bg) {
+ for(E e : bg.ess) {
+ e.bg = null;
+ add(e);
+ }
+ }
+ public void dobind(E e) {
+ for(E ex : ess) {
+ if (ex==e) continue;
+ e.p1.bind(ex.p1);
+ e.p2.bind(ex.p2);
+ }
+ }
+ public void shatter(BindingGroup bg1, BindingGroup bg2) {
+ for(E e : ess) {
+ e.shatter(e.midpoint(), bg1, bg2);
+ }
+ }
+ }
+