Replace DeferredSendHandler with OutgoingSessionRecord.

bramble-api/src/main/java/org/briarproject/bramble/api/sync/DeferredSendHandler.java

@@ -1,15 +0,0 @@
-package org.briarproject.bramble.api.sync;
-
-import java.util.Collection;
-
-/**
- * An interface for holding the IDs of messages sent and acked during an
- * outgoing {@link SyncSession} so they can be recorded in the DB as sent
- * or acked at some later time.
- */
-public interface DeferredSendHandler {
-
-	void onAckSent(Collection<MessageId> acked);
-
-	void onMessageSent(MessageId sent);
-}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/OutgoingSessionRecord.java

@@ -0,0 +1,37 @@
+package org.briarproject.bramble.api.sync;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.Collection;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+/**
+ * A container for holding the IDs of messages sent and acked during an
+ * outgoing {@link SyncSession}, so they can be recorded in the DB as sent
+ * or acked at some later time.
+ */
+@ThreadSafe
+@NotNullByDefault
+public class OutgoingSessionRecord {
+
+	private final Collection<MessageId> ackedIds = new CopyOnWriteArrayList<>();
+	private final Collection<MessageId> sentIds = new CopyOnWriteArrayList<>();
+
+	public void onAckSent(Collection<MessageId> acked) {
+		ackedIds.addAll(acked);
+	}
+
+	public void onMessageSent(MessageId sent) {
+		sentIds.add(sent);
+	}
+
+	public Collection<MessageId> getAckedIds() {
+		return ackedIds;
+	}
+
+	public Collection<MessageId> getSentIds() {
+		return sentIds;
+	}
+}