Fix CircularBuffer

pmuir · Jun 8, 2012 · 9b331e3 · 9b331e3
1 parent 1d4042a
commit 9b331e3
Showing 1 changed file with 16 additions and 6 deletions.
diff --git a/demo/src/main/java/org/jboss/jdf/example/ticketmonster/util/CircularBuffer.java b/demo/src/main/java/org/jboss/jdf/example/ticketmonster/util/CircularBuffer.java
@@ -6,32 +6,42 @@
 
 public class CircularBuffer<T> {
 
-    private List<T> buffer;
+    private T[] buffer;
 
     private volatile int cursor = 0;
 
     private final int capacity;
 
     public CircularBuffer(int capacity) {
-        buffer = Collections.synchronizedList(new ArrayList<T>());
+        buffer = (T[]) new Object[capacity];
         this.capacity = capacity;
     }
 
     public void add(T item) {
         synchronized (buffer) {
-            buffer.add (cursor++,item);
+            buffer[(cursor++)%capacity] = item;
+
         }
     }
 
     public List<T> getContents() {
+        List<T> returnedItems = new ArrayList<T>();
         synchronized (buffer) {
             if (cursor > capacity) {
-                List<T> returnedItems = buffer.subList(cursor % capacity, capacity);
-                returnedItems.addAll(buffer.subList(0, cursor % capacity));
+                for (int i= cursor % capacity; i<capacity; i++) {
+                    returnedItems.add(buffer[i]);
+                }
+                for (int i= 0; i<cursor % capacity; i++) {
+                    returnedItems.add(buffer[i]);
+                }
+
                 return returnedItems;
             } else {
-                return buffer.subList(0, cursor);
+                for (int i= 0; i<cursor; i++) {
+                    returnedItems.add(buffer[i]);
+                }
             }
         }
+        return returnedItems;
     }
 }