Invoke transaction confidence listeners when a new peer broadcasts the given transaction. Use EventListenerInvoker to run the listeners.

core/src/main/java/com/google/bitcoin/core/TransactionConfidence.java

@@ -17,6 +17,7 @@
 package com.google.bitcoin.core;
 
 import com.google.bitcoin.store.BlockStoreException;
+import com.google.bitcoin.utils.EventListenerInvoker;
 
 import java.io.Serializable;
 import java.math.BigInteger;
@@ -212,14 +213,19 @@ public class TransactionConfidence implements Serializable {
     /**
      * Called by a {@link Peer} when a transaction is pending and announced by a peer. The more peers announce the
      * transaction, the more peers have validated it (assuming your internet connection is not being intercepted).
-     * If confidence is currently unknown, sets it to {@link ConfidenceType#NOT_SEEN_IN_CHAIN}.
+     * If confidence is currently unknown, sets it to {@link ConfidenceType#NOT_SEEN_IN_CHAIN}. Listeners will be
+     * invoked in this case.
      *
      * @param address IP address of the peer, used as a proxy for identity.
      */
     public synchronized void markBroadcastBy(PeerAddress address) {
         broadcastBy.add(address);
-        if (getConfidenceType() == ConfidenceType.UNKNOWN)
+        if (getConfidenceType() == ConfidenceType.UNKNOWN) {
             setConfidenceType(ConfidenceType.NOT_SEEN_IN_CHAIN);
+            // Listeners are already run by setConfidenceType.
+        } else {
+            runListeners();
+        }
     }
 
     /**
@@ -356,16 +362,11 @@ public class TransactionConfidence implements Serializable {
     }
 
     private void runListeners() {
-        if (listeners == null) return;
+        EventListenerInvoker.invoke(listeners, new EventListenerInvoker<Listener>() {
-        for (int i = 0; i < listeners.size(); i++) {
+            @Override
-            Listener l = listeners.get(i);
+            public void invoke(Listener listener) {
-            synchronized (l) {
+                listener.onConfidenceChanged(transaction);
-                l.onConfidenceChanged(transaction);
             }
-            if (listeners.get(i) != l) {
+        });
-                // Listener removed itself.
-                i--;
-            }
-        }
     }
 }

core/src/test/java/com/google/bitcoin/core/PeerGroupTest.java

@@ -224,20 +224,32 @@ public class PeerGroupTest extends TestWithNetworkConnections {
         InventoryMessage inv = new InventoryMessage(params);
         inv.addTransaction(tx);
         
+        final Transaction[] event = new Transaction[1];
+        tx.getConfidence().addEventListener(new TransactionConfidence.Listener() {
+            public void onConfidenceChanged(Transaction tx) {
+                event[0] = tx;
+            }
+        });
+        
         // Peer 2 advertises the tx but does not download it.
         assertNull(n2.exchange(inv));
         assertEquals(0, tx.getConfidence().numBroadcastPeers());
+        assertEquals(null, event[0]);
         // Peer 1 (the download peer) advertises the tx, we download it.
         n1.exchange(inv);  // returns getdata
         n1.exchange(tx);   // returns nothing after a queue drain.
         // Two peers saw this tx hash.
         assertEquals(2, tx.getConfidence().numBroadcastPeers());
+        assertEquals(tx, event[0]);
+        event[0] = null;
         assertTrue(tx.getConfidence().getBroadcastBy().contains(n1.getPeerAddress()));
         assertTrue(tx.getConfidence().getBroadcastBy().contains(n2.getPeerAddress()));
         // A straggler reports in.
         n3.exchange(inv);
         assertEquals(3, tx.getConfidence().numBroadcastPeers());
         assertTrue(tx.getConfidence().getBroadcastBy().contains(n3.getPeerAddress()));
+        assertEquals(tx, event[0]);
+        event[0] = null;
     }
 
     @Test