ONOS-6464 interfaces for protocol-independence (PI)

And also ONOS-6553, implementation of table entry classes

Change-Id: Ia7146b1bb0aac794e19b3fd8150c042e7ec70535
diff --git a/core/api/src/main/java/org/onosproject/net/pi/model/PiActionModel.java b/core/api/src/main/java/org/onosproject/net/pi/model/PiActionModel.java
new file mode 100644
index 0000000..775c3d8
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/pi/model/PiActionModel.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2017-present Open Networking Laboratory
+ *
+ * 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.model;
+
+import com.google.common.annotations.Beta;
+
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * Model of an action with runtime parameters in a protocol-independent pipeline.
+ */
+@Beta
+public interface PiActionModel {
+    /**
+     * Returns the name of this action.
+     *
+     * @return a string value
+     */
+    String name();
+
+    /**
+     * Returns the model of this action's parameter defined by the given name, if present.
+     *
+     * @param name action name
+     * @return action parameter model
+     */
+    Optional<PiActionParamModel> param(String name);
+
+    /**
+     * Returns the list of action parameter models, ordered according to the same action parameters
+     * defined in the pipeline model.
+     *
+     * @return list of action parameter models
+     */
+    List<PiActionParamModel> params();
+}