diff --git a/src/ripple_app/shamap/SHAMap.cpp b/src/ripple_app/shamap/SHAMap.cpp
index f5bed8230..d913de3d8 100644
--- a/src/ripple_app/shamap/SHAMap.cpp
+++ b/src/ripple_app/shamap/SHAMap.cpp
@@ -17,12 +17,51 @@
 */
 //==============================================================================
 
-#ifndef STATE_MAP_BUCKETS
-#define STATE_MAP_BUCKETS 1024
-#endif
-
 SETUP_LOG (SHAMap)
 
+void SHAMap::DefaultMissingNodeHandler::operator() (uint32 refNUm)
+{
+    getApp().getOPs ().missingNodeInLedger (refNUm);
+};
+
+//------------------------------------------------------------------------------
+
+SHAMap::SHAMap (SHAMapType t, uint32 seq,
+    MissingNodeHandler missing_node_handler)
+    : mLock (this, "SHAMap", __FILE__, __LINE__)
+    , mSeq (seq)
+    , mLedgerSeq (0)
+    , mState (smsModifying)
+    , mType (t)
+    , m_missing_node_handler (missing_node_handler)
+{
+    assert (mSeq != 0);
+    if (t == smtSTATE)
+        mTNByID.rehash (STATE_MAP_BUCKETS);
+
+    root = boost::make_shared<SHAMapTreeNode> (mSeq, SHAMapNode (0, uint256 ()));
+    root->makeInner ();
+    mTNByID[*root] = root;
+}
+
+SHAMap::SHAMap (SHAMapType t, uint256 const& hash,
+    MissingNodeHandler missing_node_handler)
+    : mLock (this, "SHAMap", __FILE__, __LINE__)
+    , mSeq (1)
+    , mLedgerSeq (0)
+    , mState (smsSynching)
+    , mType (t)
+    , m_missing_node_handler (missing_node_handler)
+{
+    // FIXME: Need to acquire root node
+    if (t == smtSTATE)
+        mTNByID.rehash (STATE_MAP_BUCKETS);
+
+    root = boost::make_shared<SHAMapTreeNode> (mSeq, SHAMapNode (0, uint256 ()));
+    root->makeInner ();
+    mTNByID[*root] = root;
+}
+
 TaggedCacheType< SHAMap::TNIndex, SHAMapTreeNode, UptimeTimerAdapter>
     SHAMap::treeNodeCache ("TreeNodeCache", 65536, 60);
 
@@ -68,39 +107,6 @@ std::size_t hash_value (const SHAMapNode& mn)
     return mn.getMHash ();
 }
 
-
-SHAMap::SHAMap (SHAMapType t, uint32 seq)
-    : mLock (this, "SHAMap", __FILE__, __LINE__)
-    , mSeq (seq)
-    , mLedgerSeq (0)
-    , mState (smsModifying)
-    , mType (t)
-{
-    assert (mSeq != 0);
-    if (t == smtSTATE)
-        mTNByID.rehash (STATE_MAP_BUCKETS);
-
-    root = boost::make_shared<SHAMapTreeNode> (mSeq, SHAMapNode (0, uint256 ()));
-    root->makeInner ();
-    mTNByID[*root] = root;
-}
-
-SHAMap::SHAMap (SHAMapType t, uint256 const& hash)
-    : mLock (this, "SHAMap", __FILE__, __LINE__)
-    , mSeq (1)
-    , mLedgerSeq (0)
-    , mState (smsSynching)
-    , mType (t)
-{
-    // FIXME: Need to acquire root node
-    if (t == smtSTATE)
-        mTNByID.rehash (STATE_MAP_BUCKETS);
-
-    root = boost::make_shared<SHAMapTreeNode> (mSeq, SHAMapNode (0, uint256 ()));
-    root->makeInner ();
-    mTNByID[*root] = root;
-}
-
 SHAMap::pointer SHAMap::snapShot (bool isMutable)
 {
     SHAMap::pointer ret = boost::make_shared<SHAMap> (mType);
@@ -906,7 +912,7 @@ SHAMapTreeNode::pointer SHAMap::fetchNodeExternalNT (const SHAMapNode& id, uint2
         {
             if (mLedgerSeq != 0)
             {
-                getApp().getOPs ().missingNodeInLedger (mLedgerSeq);
+                m_missing_node_handler (mLedgerSeq);
                 mLedgerSeq = 0;
             }
 
diff --git a/src/ripple_app/shamap/SHAMap.h b/src/ripple_app/shamap/SHAMap.h
index 7cad145eb..fb857732b 100644
--- a/src/ripple_app/shamap/SHAMap.h
+++ b/src/ripple_app/shamap/SHAMap.h
@@ -32,7 +32,22 @@ enum SHAMapState
 class SHAMap
     : public CountedObject <SHAMap>
 {
+private:
+    /** Function object which handles missing nodes. */
+    typedef beast::function <void (uint32 refNum)> MissingNodeHandler;
+
+    /** Default handler which calls NetworkOPs. */
+    struct DefaultMissingNodeHandler
+    {
+        void operator() (uint32 refNUm);
+    };
+
 public:
+    enum
+    {
+        STATE_MAP_BUCKETS = 1024
+    };
+
     static char const* getCountedObjectName () { return "SHAMap"; }
 
     typedef boost::shared_ptr<SHAMap> pointer;
@@ -47,8 +62,11 @@ public:
 
 public:
     // build new map
-    explicit SHAMap (SHAMapType t, uint32 seq = 1);
-    SHAMap (SHAMapType t, uint256 const & hash);
+    explicit SHAMap (SHAMapType t, uint32 seq = 1,
+        MissingNodeHandler missing_node_handler = DefaultMissingNodeHandler());
+
+    SHAMap (SHAMapType t, uint256 const& hash,
+        MissingNodeHandler missing_node_handler = DefaultMissingNodeHandler());
 
     ~SHAMap ();
 
@@ -268,15 +286,11 @@ private:
     uint32 mSeq;
     uint32 mLedgerSeq; // sequence number of ledger this is part of
     NodeMap mTNByID;
-
     boost::shared_ptr<NodeMap> mDirtyNodes;
-
     SHAMapTreeNode::pointer root;
-
     SHAMapState mState;
-
     SHAMapType mType;
+    MissingNodeHandler m_missing_node_handler;
 };
 
 #endif
-// vim:ts=4