diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/flow/impl/SimpleFlowRuleStore.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/flow/impl/SimpleFlowRuleStore.java
index dd8dce8..8ea00e7 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/flow/impl/SimpleFlowRuleStore.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/flow/impl/SimpleFlowRuleStore.java
@@ -1,55 +1,41 @@
 package org.onlab.onos.net.trivial.flow.impl;
 
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Multimap;
 import org.onlab.onos.net.DeviceId;
 import org.onlab.onos.net.flow.DefaultFlowRule;
 import org.onlab.onos.net.flow.FlowRule;
 import org.onlab.onos.net.flow.FlowRuleEvent;
+import org.onlab.onos.net.flow.FlowRuleStore;
 
-import com.google.common.collect.HashMultimap;
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Multimap;
-
-import static org.onlab.onos.net.flow.FlowRuleEvent.Type.*;
+import static org.onlab.onos.net.flow.FlowRuleEvent.Type.RULE_ADDED;
+import static org.onlab.onos.net.flow.FlowRuleEvent.Type.RULE_REMOVED;
 
 /**
  * Manages inventory of flow rules using trivial in-memory implementation.
  */
-public class SimpleFlowRuleStore {
+public class SimpleFlowRuleStore implements FlowRuleStore {
 
     // store entries as a pile of rules, no info about device tables
     private final Multimap<DeviceId, FlowRule> flowEntries = HashMultimap.create();
 
-    /**
-     * Returns the flow entries associated with a device.
-     *
-     * @param deviceId the device ID
-     * @return the flow entries
-     */
-    Iterable<FlowRule> getFlowEntries(DeviceId deviceId) {
+    @Override
+    public Iterable<FlowRule> getFlowEntries(DeviceId deviceId) {
         return ImmutableSet.copyOf(flowEntries.get(deviceId));
     }
 
-    /**
-     * Stores a new flow rule, and generates a FlowRule for it.
-     *
-     * @param rule the flow rule to add
-     * @return a flow entry
-     */
-    FlowRule storeFlowRule(FlowRule rule) {
+    @Override
+    public FlowRule storeFlowRule(FlowRule rule) {
         DeviceId did = rule.deviceId();
         FlowRule entry = new DefaultFlowRule(did,
-                rule.selector(), rule.treatment(), rule.priority());
+                                             rule.selector(), rule.treatment(), rule.priority());
         flowEntries.put(did, entry);
         return entry;
     }
 
-    /**
-     * Stores a new flow rule, or updates an existing entry.
-     *
-     * @param rule the flow rule to add or update
-     * @return flow_added event, or null if just an update
-     */
-    FlowRuleEvent addOrUpdateFlowRule(FlowRule rule) {
+    @Override
+    public FlowRuleEvent addOrUpdateFlowRule(FlowRule rule) {
         DeviceId did = rule.deviceId();
 
         // check if this new rule is an update to an existing entry
@@ -63,13 +49,8 @@
         return new FlowRuleEvent(RULE_ADDED, rule);
     }
 
-    /**
-     *
-     * @param rule the flow rule to remove
-     * @return flow_removed event, or null if nothing removed
-     */
-    FlowRuleEvent removeFlowRule(FlowRule rule) {
-
+    @Override
+    public FlowRuleEvent removeFlowRule(FlowRule rule) {
         synchronized (this) {
             if (flowEntries.remove(rule.deviceId(), rule)) {
                 return new FlowRuleEvent(RULE_REMOVED, rule);