ONOS-7050 First stab at PI translation store

Change-Id: I7f48802b1f5d70fbe3e6cead2800855de18b9207
diff --git a/core/api/src/main/java/org/onosproject/net/pi/runtime/PiActionGroup.java b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiActionGroup.java
index 1d9a94b..9084bea 100644
--- a/core/api/src/main/java/org/onosproject/net/pi/runtime/PiActionGroup.java
+++ b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiActionGroup.java
@@ -34,7 +34,7 @@
  * Instance of an action group of a protocol-independent pipeline.
  */
 @Beta
-public final class PiActionGroup {
+public final class PiActionGroup implements PiEntity {
 
     private final PiActionGroupId id;
     private final PiActionGroupType type;
@@ -125,6 +125,11 @@
         return new Builder();
     }
 
+    @Override
+    public PiEntityType piEntityType() {
+        return PiEntityType.GROUP;
+    }
+
     /**
      * Builder of action groups.
      */
diff --git a/core/api/src/main/java/org/onosproject/net/pi/runtime/PiEntity.java b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiEntity.java
new file mode 100644
index 0000000..c3d5a01
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiEntity.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2017-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.net.pi.runtime;
+
+import com.google.common.annotations.Beta;
+
+/**
+ * Abstraction of an entity of a protocol-independent that can be read or write
+ * at runtime.
+ */
+@Beta
+public interface PiEntity {
+
+    /**
+     * Returns the type of this entity.
+     *
+     * @return entity type
+     */
+    PiEntityType piEntityType();
+}
diff --git a/core/api/src/main/java/org/onosproject/net/pi/runtime/PiEntityType.java b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiEntityType.java
new file mode 100644
index 0000000..e01e520
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiEntityType.java
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2017-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.net.pi.runtime;
+
+import com.google.common.annotations.Beta;
+
+/**
+ * Type of runtime entity of a protocol-independent pipeline.
+ */
+@Beta
+public enum PiEntityType {
+    /**
+     * Table entry.
+     */
+    TABLE_ENTRY,
+
+    /**
+     * Action profile group.
+     */
+    GROUP
+}
diff --git a/core/api/src/main/java/org/onosproject/net/pi/runtime/PiTableEntry.java b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiTableEntry.java
index cd7e493..5770c6b 100644
--- a/core/api/src/main/java/org/onosproject/net/pi/runtime/PiTableEntry.java
+++ b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiTableEntry.java
@@ -30,7 +30,7 @@
  * Instance of a table entry in a protocol-independent pipeline.
  */
 @Beta
-public final class PiTableEntry {
+public final class PiTableEntry implements PiEntity {
 
     public static final PiTableEntry EMTPY = new PiTableEntry();
 
@@ -160,6 +160,11 @@
         return new Builder();
     }
 
+    @Override
+    public PiEntityType piEntityType() {
+        return PiEntityType.TABLE_ENTRY;
+    }
+
     public static final class Builder {
 
         private PiTableId tableId;