From e8138c21b02b33511807c947df52af2a933cc59f Mon Sep 17 00:00:00 2001
From: Adam Mackler <AdamMackler@gmail.com>
Date: Wed, 4 Feb 2015 06:06:27 -0500
Subject: [PATCH] Change PeerGroup.addPeerFilterProvider to return a
 ListenableFuture<BloomFilter>

Currently 'addPeerFilterProvider()` returns `void`.  After this patch it
returns the `ListenableFuture<BloomFilter>` that is returned by its
invocation of `recalculateFastCatchupAndFilter()`.
---
 core/src/main/java/org/bitcoinj/core/PeerGroup.java | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/core/src/main/java/org/bitcoinj/core/PeerGroup.java b/core/src/main/java/org/bitcoinj/core/PeerGroup.java
index ee71e492..39f1a99e 100644
--- a/core/src/main/java/org/bitcoinj/core/PeerGroup.java
+++ b/core/src/main/java/org/bitcoinj/core/PeerGroup.java
@@ -961,8 +961,14 @@ public class PeerGroup implements TransactionBroadcaster {
      *
      * <p>Note that this should be done before chain download commences because if you add a listener with keys earlier
      * than the current chain head, the relevant parts of the chain won't be redownloaded for you.</p>
+     *
+     * <p>This method invokes {@link PeerGroup#recalculateFastCatchupAndFilter(FilterRecalculateMode)}.
+     * The return value of this method is the <code>ListenableFuture</code> returned by that invocation.</p>
+     *
+     * @return a future that completes once each <code>Peer</code> in this group has had its
+     *         <code>BloomFilter</code> (re)set.
      */
-    public void addPeerFilterProvider(PeerFilterProvider provider) {
+    public ListenableFuture<BloomFilter> addPeerFilterProvider(PeerFilterProvider provider) {
         lock.lock();
         try {
             checkNotNull(provider);
@@ -981,8 +987,9 @@ public class PeerGroup implements TransactionBroadcaster {
             // if a key is added. Of course, by then we may have downloaded the chain already. Ideally adding keys would
             // automatically rewind the block chain and redownload the blocks to find transactions relevant to those keys,
             // all transparently and in the background. But we are a long way from that yet.
-            recalculateFastCatchupAndFilter(FilterRecalculateMode.SEND_IF_CHANGED);
+            ListenableFuture<BloomFilter> future = recalculateFastCatchupAndFilter(FilterRecalculateMode.SEND_IF_CHANGED);
             updateVersionMessageRelayTxesBeforeFilter(getVersionMessage());
+            return future;
         } finally {
             lock.unlock();
         }