--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/dancres/blitz/UIDSet.java	Sat Mar 21 11:00:06 2009 +0000
@@ -0,0 +1,46 @@
+package org.dancres.blitz;
+
+import java.util.Set;
+import java.util.HashSet;
+import java.util.ArrayList;
+
+/**
+ * A set of UID's that is guarenteed to contain no duplicates and limits it's
+ * size to the specified capacity
+ */
+public class UIDSet {
+    private Set theFilter = new HashSet();
+    private ArrayList theMembers = new ArrayList();
+    private long theCapacity;
+
+    UIDSet(long aMaxSize) {
+        theCapacity = aMaxSize;
+    }
+
+    void add(SpaceEntryUID aUID) {
+        synchronized(theFilter) {
+            if (isFull())
+                return;
+
+            if (! theFilter.contains(aUID)) {
+                theFilter.add(aUID);
+                theMembers.add(aUID);
+            }
+        }
+    }
+
+    boolean isFull() {
+        synchronized(theFilter) {
+            return (theFilter.size() == theCapacity);
+        }
+    }
+
+    SpaceEntryUID pop() {
+        synchronized(theFilter) {
+            if (theMembers.size() == 0)
+                return null;
+            else
+                return (SpaceEntryUID) theMembers.remove(theMembers.size() - 1);
+        }
+    }
+}