api and manager for statistic service
Change-Id: If00b8b43a2bd780ae3c05321697896290fb0f415
diff --git a/core/api/src/main/java/org/onlab/onos/net/statistic/StatisticStore.java b/core/api/src/main/java/org/onlab/onos/net/statistic/StatisticStore.java
new file mode 100644
index 0000000..d0d625c
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/statistic/StatisticStore.java
@@ -0,0 +1,45 @@
+package org.onlab.onos.net.statistic;
+
+import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.flow.FlowEntry;
+import org.onlab.onos.net.flow.FlowRule;
+
+import java.util.Set;
+
+/**
+ * Store to house the computed statistics.
+ */
+public interface StatisticStore {
+
+ /**
+ * Lay the foundation for receiving flow stats for this rule.
+ * @param rule a {@link org.onlab.onos.net.flow.FlowRule}
+ */
+ void prepareForStatistics(FlowRule rule);
+
+ /**
+ * Remove entries associated with this rule.
+ a @param rule {@link org.onlab.onos.net.flow.FlowRule}
+ */
+ void removeFromStatistics(FlowRule rule);
+
+ /**
+ * Adds a stats observation for a flow rule.
+ * @param rule a {@link org.onlab.onos.net.flow.FlowEntry}
+ */
+ void addOrUpdateStatistic(FlowEntry rule);
+
+ /**
+ * Fetches the current observed stats values.
+ * @param connectPoint the port to fetch information for
+ * @return set of current flow rules
+ */
+ Set<FlowEntry> getCurrentStatistic(ConnectPoint connectPoint);
+
+ /**
+ * Fetches the current observed stats values.
+ * @param connectPoint the port to fetch information for
+ * @return set of current values
+ */
+ Set<FlowEntry> getPreviousStatistic(ConnectPoint connectPoint);
+}