/** implementation of <tt>Topology</tt> for any class via equals()/hashCode() */
public class DiscreteTopology<V> implements Topology<V> {
+ private static final DiscreteTopology empty = new DiscreteTopology();
+
HashSet<V> hs = new HashSet<V>();
public DiscreteTopology() { }
public DiscreteTopology(V v) { hs.add(v); }
- DiscreteTopology(HashSet<V> hs) { this.hs.addAll(hs); }
+ DiscreteTopology(HashSet<V> hs) { this.hs.addAll(hs); }
- public Topology<V> fresh() { return new DiscreteTopology<V>(); }
- public Topology<V> dup() { return new DiscreteTopology<V>(this.hs); }
+ public Topology<V> empty() { return (Topology<V>)empty; }
public HashSet<V> hs() {
HashSet<V> ret = new HashSet<V>();
return ret;
}
- public void add(Topology<V> t) { hs.addAll(((DiscreteTopology<V>)t).hs); }
- public void remove(Topology<V> t) { hs.removeAll(((DiscreteTopology<V>)t).hs); }
- public void add(V v) { hs.add(v); }
- public void remove(V v) { hs.remove(v); }
public boolean contains(V v) { return hs.contains(v); }
- public Topology<V> complement() { /*return dup(hs.complement());*/ throw new Error(); }
- public Topology<V> intersect(Topology<V> t) { return new DiscreteTopology(hs().retainAll(((DiscreteTopology<V>)t).hs)); }
- public Topology<V> minus(Topology<V> t) { return new DiscreteTopology(hs().removeAll(((DiscreteTopology<V>)t).hs)); }
- public Topology<V> union(Topology<V> t) { return new DiscreteTopology(hs().addAll(((DiscreteTopology<V>)t).hs)); }
- public boolean disjoint(Topology<V> t) { return ((DiscreteTopology)intersect(t)).size()==0; }
- public boolean containsAll(Topology<V> t) { return hs.containsAll(((DiscreteTopology<V>)t).hs); }
+ public Topology<V> unwrap() { return this; }
+ public Topology<V> complement() { throw new Error(); }
+ public Topology<V> intersect(Topology<V> t) { return new DiscreteTopology(hs().retainAll(((DiscreteTopology<V>)t.unwrap()).hs)); }
+ public Topology<V> minus(Topology<V> t) { return new DiscreteTopology(hs().removeAll(((DiscreteTopology<V>)t.unwrap()).hs)); }
+ public Topology<V> union(Topology<V> t) { return new DiscreteTopology(hs().addAll(((DiscreteTopology<V>)t.unwrap()).hs)); }
+ public boolean disjoint(Topology<V> t) { return ((DiscreteTopology)intersect(t).unwrap()).size()==0; }
+ public boolean containsAll(Topology<V> t) { return hs.containsAll(((DiscreteTopology<V>)t.unwrap()).hs); }
public int hashCode() { return hs.hashCode(); }
public boolean equals(Object o) { return o!=null && o instanceof DiscreteTopology && ((DiscreteTopology<V>)o).hs.equals(hs); }