[ONOS-5473] Defining VirtualFlowRuleProvider interface.

Changes
1. Defined provider/registry structure for virtual providers
2. Added VirtualFlowRuleProvider
3. Added VirtualFlowRuleProivderService
4. Added VirtaulFlowRuleProviderRegistry

Change-Id: I3aa0eaee050177d06cade88c63df13f165ca5cf2
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualFlowRuleProvider.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualFlowRuleProvider.java
new file mode 100644
index 0000000..89f1f43
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualFlowRuleProvider.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2016-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.incubator.net.virtual.provider;
+
+import org.onosproject.incubator.net.virtual.NetworkId;
+import org.onosproject.net.flow.FlowRule;
+
+/**
+ * Abstraction of a virtual flow rule provider.
+ * This provider virtualizes and de-virtualizes FlowRule.
+ * See {@link org.onosproject.net.flow.FlowRule}.
+ */
+public interface VirtualFlowRuleProvider extends VirtualProvider {
+
+    /**
+     * Instructs the provider to apply the specified flow rules to their
+     * respective virtual devices.
+     *
+     * @param networkId the identity of the virtual network where this rule applies
+     * @param flowRules one or more flow rules
+     */
+    void applyFlowRule(NetworkId networkId, FlowRule... flowRules);
+
+    /**
+     * Instructs the provider to remove the specified flow rules to their
+     * respective virtual devices.
+     *
+     * @param networkId the identity of the virtual network where this rule applies
+     * @param flowRules one or more flow rules
+     */
+    void removeFlowRule(NetworkId networkId, FlowRule... flowRules);
+}
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualFlowRuleProviderRegistry.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualFlowRuleProviderRegistry.java
new file mode 100644
index 0000000..4d0ea63
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualFlowRuleProviderRegistry.java
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2016-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.incubator.net.virtual.provider;
+
+/**
+ * Abstraction for a flow rule provider registry.
+ */
+public interface VirtualFlowRuleProviderRegistry
+        extends VirtualProviderRegistry<VirtualFlowRuleProvider,
+        VirtualFlowRuleProviderService> {
+}
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualFlowRuleProviderService.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualFlowRuleProviderService.java
new file mode 100644
index 0000000..3f6bf8c
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualFlowRuleProviderService.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2016-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.incubator.net.virtual.provider;
+
+import org.onosproject.incubator.net.virtual.NetworkId;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.flow.FlowEntry;
+import org.onosproject.net.flow.TableStatisticsEntry;
+
+import java.util.List;
+
+/**
+ * Service through which virtual flow rule providers can inject information into
+ * the core.
+ */
+public interface VirtualFlowRuleProviderService
+        extends VirtualProviderService<VirtualFlowRuleProvider> {
+
+    /**
+     * Signals that a flow rule that was previously installed has been removed.
+     *
+     * @param networkId the identity of the virtual network where this rule applies
+     * @param flowEntry removed flow entry
+     */
+    void flowRemoved(NetworkId networkId, FlowEntry flowEntry);
+
+    /**
+     * Pushes the collection of flow entries currently applied on the given
+     * virtual device.
+     *
+     * @param networkId the identity of the virtual network where this rule applies
+     * @param deviceId device identifier
+     * @param flowEntries collection of flow rules
+     */
+    void pushFlowMetrics(NetworkId networkId, DeviceId deviceId,
+                         Iterable<FlowEntry> flowEntries);
+
+    /**
+     * Pushes the collection of flow entries currently applied on the given
+     * device without flowMissing process.
+     *
+     * @param networkId the identity of the virtual network where this rule applies
+     * @param deviceId device identifier
+     * @param flowEntries collection of flow rules
+     */
+    void pushFlowMetricsWithoutFlowMissing(NetworkId networkId, DeviceId deviceId,
+                                           Iterable<FlowEntry> flowEntries);
+
+    /**
+     * Pushes the collection of table statistics entries currently extracted
+     * from the given virtual device.
+     *
+     * @param networkId the identity of the virtual network where this rule applies
+     * @param deviceId device identifier
+     * @param tableStatsEntries collection of flow table statistics entries
+     */
+    void pushTableStatistics(NetworkId networkId, DeviceId deviceId,
+                             List<TableStatisticsEntry> tableStatsEntries);
+
+}
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualProvider.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualProvider.java
new file mode 100644
index 0000000..0416600
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualProvider.java
@@ -0,0 +1,26 @@
+/*
+ * Copyright 2016-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.incubator.net.virtual.provider;
+
+/**
+ * Abstraction of a provider of information about virtual network environment.
+ * The role of virtual providers is to translate virtual objects into physical
+ * objects, vice versa.
+ */
+public interface VirtualProvider {
+
+}
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualProviderRegistry.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualProviderRegistry.java
new file mode 100644
index 0000000..8240139
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualProviderRegistry.java
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2016-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.incubator.net.virtual.provider;
+
+import java.util.Set;
+
+/** Registry for tracking information virtual providers with the core.
+ * @param <P> type of the information virtual provider
+ * @param <S> type of the provider virtual service
+ */
+
+public interface VirtualProviderRegistry<P extends VirtualProvider,
+            S extends VirtualProviderService<P>> {
+
+    /**
+     * Registers the supplied virtual provider with the virtual core.
+     *
+     * @param provider virtual provider to be registered
+     * @return service for injecting information into core
+     * @throws java.lang.IllegalArgumentException if the provider is registered already
+     */
+    S register(P provider);
+
+    /**
+     * Unregisters the supplied virtual provider.
+     * As a result the previously issued virtual provider service
+     * will be invalidated and any subsequent invocations
+     * of its methods may throw {@link java.lang.IllegalStateException}.
+     * Unregistering a virtual provider that has not been previously registered
+     * result in a no-op.
+     *
+     * @param provider provider to be unregistered
+     */
+    void unregister(P provider);
+
+    /**
+     * Returns a set of currently registered virtual providers.
+     *
+     * @return set of virtual providers
+     */
+    Set<P> getProviders();
+}
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualProviderService.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualProviderService.java
new file mode 100644
index 0000000..668cb49
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/VirtualProviderService.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2016-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.incubator.net.virtual.provider;
+
+/**
+ * Abstraction of a service through which virtual providers can inject information
+ * about the network environment into the virtual core.
+ *
+ * @param <P> type of the information virtual provider
+ */
+
+public interface VirtualProviderService<P extends VirtualProvider> {
+    /**
+     * Returns the virtual provider to which this service has been issued.
+     *
+     * @return virtual provider to which this service has been assigned
+     */
+    P provider();
+}
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/package-info.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/package-info.java
new file mode 100644
index 0000000..36cd14d
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/provider/package-info.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2016-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.
+ */
+
+/**
+ * Network virtualization data models and services.
+ */
+package org.onosproject.incubator.net.virtual.provider;
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