From b4657f9d04a5e0d30fa6d275ef933c420d9016c8 Mon Sep 17 00:00:00 2001
From: Ajay <ajayl.bro@gmail.com>
Date: Fri, 2 Sep 2016 06:10:59 +0000
Subject: [PATCH] Bug-6621: ModifiedNodeDoesNotExistException encountered while
 building Linkstate topology - added null check in BGP topology builder
 removeObject() method to   gracefully handle issue created by BUG-6577 - when
 destroying operational topology to recover from a failure,   flush the
 internally stored topology info as well so that both are in sync

Change-Id: Id239d74738d43dd63177aa3b2ba1d3d9136c3338
Signed-off-by: Ajay <ajayl.bro@gmail.com>
---
 .../provider/AbstractReachabilityTopologyBuilder.java  | 10 ++++++++++
 .../bgp/topology/provider/AbstractTopologyBuilder.java |  3 +++
 .../topology/provider/LinkstateTopologyBuilder.java    | 10 ++++++++++
 3 files changed, 23 insertions(+)

diff --git a/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/AbstractReachabilityTopologyBuilder.java b/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/AbstractReachabilityTopologyBuilder.java
index 2914a3ec06..111f48ca82 100644
--- a/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/AbstractReachabilityTopologyBuilder.java
+++ b/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/AbstractReachabilityTopologyBuilder.java
@@ -142,6 +142,11 @@ abstract class AbstractReachabilityTopologyBuilder<T extends Route> extends Abst
 
     @Override
     protected final void removeObject(final ReadWriteTransaction trans, final InstanceIdentifier<T> id, final T value) {
+        if (value == null) {
+            LOG.error("Empty before-data received in delete data change notification for instance id {}", id);
+            return;
+        }
+
         final NodeId ni = advertizingNode(getAttributes(value));
         if (ni == null) {
             return;
@@ -174,4 +179,9 @@ abstract class AbstractReachabilityTopologyBuilder<T extends Route> extends Abst
             }
         }
     }
+
+    @Override
+    protected void clearTopology() {
+        this.nodes.clear();
+    }
 }
diff --git a/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/AbstractTopologyBuilder.java b/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/AbstractTopologyBuilder.java
index 356060becc..de1070ab83 100644
--- a/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/AbstractTopologyBuilder.java
+++ b/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/AbstractTopologyBuilder.java
@@ -140,6 +140,8 @@ public abstract class AbstractTopologyBuilder<T extends Route> implements AutoCl
 
     protected abstract void removeObject(ReadWriteTransaction trans, InstanceIdentifier<T> id, T value);
 
+    protected abstract void clearTopology();
+
     @Override
     public final InstanceIdentifier<Topology> getInstanceIdentifier() {
         return this.topology;
@@ -259,6 +261,7 @@ public abstract class AbstractTopologyBuilder<T extends Route> implements AutoCl
         } catch (final TransactionCommitFailedException e) {
             LOG.error("Unable to reset operational topology {} (transaction {})", this.topology, trans.getIdentifier(), e);
         }
+        clearTopology();
     }
 
     /**
diff --git a/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/LinkstateTopologyBuilder.java b/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/LinkstateTopologyBuilder.java
index 05b727481a..97434d7916 100644
--- a/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/LinkstateTopologyBuilder.java
+++ b/bgp/topology-provider/src/main/java/org/opendaylight/bgpcep/bgp/topology/provider/LinkstateTopologyBuilder.java
@@ -925,6 +925,11 @@ public class LinkstateTopologyBuilder extends AbstractTopologyBuilder<LinkstateR
     @Override
     protected void removeObject(final ReadWriteTransaction trans,
             final InstanceIdentifier<LinkstateRoute> id, final LinkstateRoute value) {
+        if (value == null) {
+            LOG.error("Empty before-data received in delete data change notification for instance id {}", id);
+            return;
+        }
+
         final UriBuilder base = new UriBuilder(value);
 
         final ObjectType t = value.getObjectType();
@@ -944,4 +949,9 @@ public class LinkstateTopologyBuilder extends AbstractTopologyBuilder<LinkstateR
     protected InstanceIdentifier<LinkstateRoute> getRouteWildcard(final InstanceIdentifier<Tables> tablesId) {
         return tablesId.child((Class)LinkstateRoutes.class).child(LinkstateRoute.class);
     }
+
+    @Override
+    protected void clearTopology() {
+        this.nodes.clear();
+    }
 }
-- 
2.36.6