reliable multicast: prune received list

1 files changed, 50 insertions, 7 deletions

diff --git a/src/main/java/derms/net/rmulticast/ReceivedSet.java b/src/main/java/derms/net/rmulticast/ReceivedSet.java
index 339a714..963b321 100644
--- a/src/main/java/derms/net/rmulticast/ReceivedSet.java
+++ b/src/main/java/derms/net/rmulticast/ReceivedSet.java
@@ -1,14 +1,18 @@
 package derms.net.rmulticast;
 
 import java.io.Serializable;
-import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
 
 class ReceivedSet<T extends Serializable & Hashable> {
-    private final Set<Message<T>> received;
+    private final Queue<Message<T>> received;
 
     ReceivedSet() {
-        this.received = new ConcurrentHashMap<Message<T>, Void>().keySet();
+        this.received = new ConcurrentLinkedQueue<Message<T>>();
     }
 
     void add(Message<T> e) {
@@ -16,10 +20,49 @@ class ReceivedSet<T extends Serializable & Hashable> {
     }
 
     // TODO: faster search.
-    boolean contains(MessageID mid) {
+    Message<T> getByID(MessageID mid) throws NoSuchElementException {
         for (Message<T> msg : received)
             if (msg.id().equals(mid))
-                return true;
-        return false;
+                return msg;
+        throw new NoSuchElementException("message " + mid + " not in received list.");
+    }
+
+    boolean contains(MessageID mid) {
+        try {
+            Message<T> msg = getByID(mid);
+            return true;
+        } catch (NoSuchElementException e) {
+            return false;
+        }
+    }
+
+    /** Remove the specified message from the set, if it is present. */
+    void remove(Message<T> msg) {
+        received.remove(msg);
+    }
+
+    /** Retrieves, but does not remove, the oldest message, or returns null if the set is empty. */
+    Message<T> peekOldest() {
+        return received.peek();
+    }
+
+    Message<T> mostRecentSentBy(InetAddress member) throws NoSuchElementException {
+        Message<T> recent = null;
+        for (Message<T> msg : received) {
+            if (msg.sender.equals(member))
+                recent = msg;
+        }
+        if (recent == null)
+            throw new NoSuchElementException("no message from " + member + " in received list.");
+        return recent;
+    }
+
+    List<Message<T>> allSentBy(InetAddress sender) {
+        List<Message<T>> sent = new ArrayList<Message<T>>();
+       for (Message<T> msg : received) {
+           if (msg.sender.equals(sender))
+               sent.add(msg);
+       }
+       return sent;
     }
 }