Trigger pipeconf deploy right after registration

Without waiting for the next pipeconf watchdog periodic probe.
To support this, this patch extends the PiPipeconfService to advertise
pipeconf registration events.

Change-Id: Ib44f1813bd37083c666a5e7980de320ce469c2d2
diff --git a/core/api/src/main/java/org/onosproject/net/pi/service/PiPipeconfEvent.java b/core/api/src/main/java/org/onosproject/net/pi/service/PiPipeconfEvent.java
new file mode 100644
index 0000000..339912d
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/pi/service/PiPipeconfEvent.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2019-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.service;
+
+import org.onosproject.event.AbstractEvent;
+import org.onosproject.net.pi.model.PiPipeconf;
+import org.onosproject.net.pi.model.PiPipeconfId;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Event related to the PiPipeconfService.
+ */
+public class PiPipeconfEvent extends AbstractEvent<PiPipeconfEvent.Type, PiPipeconfId> {
+
+    private final PiPipeconf pipeconf;
+
+    /**
+     * Type of pipeconf event.
+     */
+    public enum Type {
+        REGISTERED,
+        UNREGISTERED
+    }
+
+    /**
+     * Creates anew pipeconf event for the given type and pipeconf.
+     *
+     * @param type     type of event
+     * @param pipeconf pipeconf
+     */
+    public PiPipeconfEvent(Type type, PiPipeconf pipeconf) {
+        super(type, checkNotNull(pipeconf).id());
+        this.pipeconf = pipeconf;
+    }
+
+
+    /**
+     * Creates anew pipeconf event for the given type and pipeconf ID.
+     *
+     * @param type       type of event
+     * @param pipeconfId pipeconf ID
+     */
+    public PiPipeconfEvent(Type type, PiPipeconfId pipeconfId) {
+        super(type, pipeconfId);
+        pipeconf = null;
+    }
+
+    /**
+     * Returns the pipeconf instance associated to this event, or null if one
+     * was not provided. For example, {@link Type#UNREGISTERED} events are not
+     * expected to carry the pipeconf instance that was unregistered, but just
+     * the ID (via {@link #subject()}).
+     *
+     * @return pipeconf instance or null
+     */
+    public PiPipeconf pipeconf() {
+        return pipeconf;
+    }
+}
diff --git a/core/api/src/main/java/org/onosproject/net/pi/service/PiPipeconfListener.java b/core/api/src/main/java/org/onosproject/net/pi/service/PiPipeconfListener.java
new file mode 100644
index 0000000..11209e1
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/pi/service/PiPipeconfListener.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2019-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.service;
+
+import org.onosproject.event.EventListener;
+
+/**
+ * Listener of pipeconf events.
+ */
+public interface PiPipeconfListener extends EventListener<PiPipeconfEvent> {
+}
diff --git a/core/api/src/main/java/org/onosproject/net/pi/service/PiPipeconfService.java b/core/api/src/main/java/org/onosproject/net/pi/service/PiPipeconfService.java
index 9943352..d24348d 100644
--- a/core/api/src/main/java/org/onosproject/net/pi/service/PiPipeconfService.java
+++ b/core/api/src/main/java/org/onosproject/net/pi/service/PiPipeconfService.java
@@ -17,6 +17,7 @@
 package org.onosproject.net.pi.service;
 
 import com.google.common.annotations.Beta;
+import org.onosproject.event.ListenerService;
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.pi.model.PiPipeconf;
 import org.onosproject.net.pi.model.PiPipeconfId;
@@ -27,12 +28,12 @@
  * A service to manage the configurations of protocol-independent pipelines.
  */
 @Beta
-public interface PiPipeconfService {
+public interface PiPipeconfService extends ListenerService<PiPipeconfEvent, PiPipeconfListener> {
 
     // TODO: we might want to extend ListenerService to support the broadcasting of PipeconfEvent.
 
     /**
-     * Registers the given pipeconf.
+     * Registers the given pipeconf making it available to other subsystems.
      *
      * @param pipeconf a pipeconf
      * @throws IllegalStateException if the same pipeconf identifier is already
@@ -41,17 +42,14 @@
     void register(PiPipeconf pipeconf) throws IllegalStateException;
 
     /**
-     * Unregisters the Pipeconf identified by the given PiPipeconfId.
-     * Unregistering a Pipeconf removes it from the ONOS controller, thus making
-     * it un-capable of controlling (e.g installing flow rules) the devices that
-     * have the pipeconf's P4 program deployed. For now this method DOES NOT
-     * remove the P4 program from the devices.
+     * Unregisters the given pipeconf. Once unregistered, other subsystems will
+     * not be able to access the pipeconf content.
      *
      * @param pipeconfId a pipeconfId
      * @throws IllegalStateException if the same pipeconf identifier is already
      *                               registered.
      */
-    void remove(PiPipeconfId pipeconfId) throws IllegalStateException;
+    void unregister(PiPipeconfId pipeconfId) throws IllegalStateException;
 
     /**
      * Returns all pipeconfs registered.