added DiscreteTopology

darcs-hash:20051225102837-5007d-98bb27c7f4d67e1461c6dccdc1ddfbce81b8f1b5.gz

diff --git a/src/edu/berkeley/sbp/util/DiscreteTopology.java b/src/edu/berkeley/sbp/util/DiscreteTopology.java
new file mode 100644 (file)
index 0000000..f78bdae
--- /dev/null
+++ b/src/edu/berkeley/sbp/util/DiscreteTopology.java
@@ -0,0 +1,43 @@
+package edu.berkeley.sbp.util;
+import java.io.*;
+import java.util.*;
+import java.lang.reflect.*;
+import java.lang.ref.*;
+import edu.berkeley.sbp.util.*;
+import edu.berkeley.sbp.*;
+
+/** implementation of <tt>Topology</tt> for any class via equals()/hashCode() */
+public class DiscreteTopology<V> implements Topology<V> {
+
+    HashSet<V> hs = new HashSet<V>();
+
+    public DiscreteTopology()              { }
+    public DiscreteTopology(V v)           { hs.add(v); }
+    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 HashSet<V> hs() {
+        HashSet<V> ret = new HashSet<V>();
+        ret.addAll(hs);
+        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 int     hashCode()                          { return hs.hashCode(); }
+    public boolean equals(Object o)                    { return o!=null && o instanceof DiscreteTopology && ((DiscreteTopology<V>)o).hs.equals(hs); }
+    public int size() { return hs.size(); }
+}