[ONOS-5793] YANG model and model registry definition

Change-Id: I7b7113e0018b687d328ee43c452b982d4f34c48b
diff --git a/runtime/api/pom.xml b/runtime/api/pom.xml
new file mode 100644
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--- /dev/null
+++ b/runtime/api/pom.xml
@@ -0,0 +1,63 @@
+<!--
+  ~ 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.
+  -->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.onosproject</groupId>
+        <artifactId>onos-yang-runtime</artifactId>
+        <version>1.12-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>onos-yang-runtime-api</artifactId>
+    <packaging>jar</packaging>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onos-yang-model</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.onosproject</groupId>
+            <artifactId>onos-yang-compiler-api</artifactId>
+            <version>1.12-SNAPSHOT</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>3.0.2</version>
+                <configuration>
+                    <skipIfEmpty>true</skipIfEmpty>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>default</id>
+                        <goals>
+                            <goal>test-jar</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>
diff --git a/runtime/api/src/main/java/org/onosproject/yang/runtime/api/AppModuleInfo.java b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/AppModuleInfo.java
new file mode 100644
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--- /dev/null
+++ b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/AppModuleInfo.java
@@ -0,0 +1,58 @@
+/*
+ * 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.yang.runtime.api;
+
+import java.util.List;
+
+/**
+ * Representation of an entity which defines additional information about the
+ * module required for the model registration.
+ */
+public interface AppModuleInfo {
+
+    /**
+     * Returns the module class which will be required by YANG runtime to
+     * obtain the class loader.
+     *
+     * @return module JAVA class
+     */
+    Class<?> getModuleClass();
+
+    /**
+     * Sets module class.
+     *
+     * @param moduleClass module class
+     */
+    void setModuleClass(Class<?> moduleClass);
+
+    /**
+     * Reference RFC 7895
+     * Retrieves the list of YANG feature names from this module that are
+     * supported by the server, regardless of whether they are
+     * defined in the module or any included submodule.
+     *
+     * @return list of YANG features
+     */
+    List<String> getFeatureList();
+
+    /**
+     * Adds supported feature.
+     *
+     * @param feature supported feature
+     */
+    void addFeature(String feature);
+}
diff --git a/runtime/api/src/main/java/org/onosproject/yang/runtime/api/DataFormat.java b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/DataFormat.java
new file mode 100644
index 0000000..1ba26fb
--- /dev/null
+++ b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/DataFormat.java
@@ -0,0 +1,27 @@
+/*
+ * 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.yang.runtime.api;
+
+/**
+ * Abstraction of configuration data-format descriptor.
+ */
+public interface DataFormat {
+
+    // TODO: should this be an enum instead with choices fixed at compile-time?
+    // name, e.g. "XML", "JSON"
+
+}
diff --git a/runtime/api/src/main/java/org/onosproject/yang/runtime/api/ModelRegistrationParam.java b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/ModelRegistrationParam.java
new file mode 100644
index 0000000..c1d2bf5
--- /dev/null
+++ b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/ModelRegistrationParam.java
@@ -0,0 +1,58 @@
+/*
+ * 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.yang.runtime.api;
+
+import org.onosproject.yang.YangModel;
+import org.onosproject.yang.YangModuleId;
+
+/**
+ * Representation of model registration parameters.
+ */
+public interface ModelRegistrationParam {
+
+    /**
+     * Returns YANG model.
+     *
+     * @return YANG model
+     */
+    YangModel getYangModel();
+
+    /**
+     * Sets YANG model.
+     *
+     * @param model YANG model
+     */
+    void setYangModel(YangModel model);
+
+    /**
+     * Returns extended app related information of a module/sub-module.
+     *
+     * @param id YANG module identifier
+     * @return application module information
+     */
+    AppModuleInfo getAppModuleInfo(YangModuleId id);
+
+    /**
+     * Adds application module information associated with module identifier.
+     * It's expected that application should provide information for all the
+     * YANG modules.
+     *
+     * @param id   YANG module identifier
+     * @param info application information associated with module identifier
+     */
+    void addAppModuleInfo(YangModuleId id, AppModuleInfo info);
+}
diff --git a/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangModelRegistry.java b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangModelRegistry.java
new file mode 100644
index 0000000..036c399
--- /dev/null
+++ b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangModelRegistry.java
@@ -0,0 +1,50 @@
+/*
+ * 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.yang.runtime.api;
+
+import org.onosproject.yang.YangModel;
+
+import java.util.Set;
+
+/**
+ * Registry of YANG models known to YANG runtime.
+ */
+public interface YangModelRegistry {
+
+    /**
+     * Registers a new model.
+     *
+     * @param param parameters having model to be registered with additional
+     *              informations provided by app
+     */
+    void registerModel(ModelRegistrationParam param);
+
+    /**
+     * Unregisters the specified model.
+     *
+     * @param param parameters having model to be registered with additional
+     *              informations provided by app
+     */
+    void unregisterModel(ModelRegistrationParam param);
+
+    /**
+     * Returns collection of all registered models.
+     *
+     * @return collection of models
+     */
+    Set<YangModel> getModels();
+}
diff --git a/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangRuntimeService.java b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangRuntimeService.java
new file mode 100644
index 0000000..745eaf5
--- /dev/null
+++ b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangRuntimeService.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.yang.runtime.api;
+
+import org.onosproject.yang.model.DataNode;
+
+import java.io.InputStream;
+
+/**
+ * Service for encoding and decoding between internal and external model
+ * representations.
+ */
+public interface YangRuntimeService {
+
+    /**
+     * Decodes the external representation of a configuration model from the
+     * specified input stream and into an in-memory representation.
+     *
+     * @param external input stream carrying external representation of
+     *                 configuration data
+     * @param format   data format of the provided external representation
+     * @return in-memory representation of configuration data
+     */
+    DataNode decode(InputStream external, DataFormat format);
+
+    /**
+     * Encodes the internal in-memory representation of a configuration model
+     * to an external representation consumable from the resulting input stream.
+     *
+     * @param internal in-memory representation of configuration data
+     * @param format   expected data format of the external representation
+     * @return input stream carrying external representation of
+     * configuration data
+     */
+    InputStream encode(DataNode internal, DataFormat format);
+
+}
diff --git a/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangSerializer.java b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangSerializer.java
new file mode 100644
index 0000000..3409d0b
--- /dev/null
+++ b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangSerializer.java
@@ -0,0 +1,65 @@
+/*
+ * 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.yang.runtime.api;
+
+import org.onosproject.yang.model.DataNode;
+
+import java.io.InputStream;
+
+/**
+ * Abstraction of entity capable of encoding and decoding arbitrary
+ * {@link DataNode} structures, which are in-memory representations of
+ * YANG models, to and from various external representations, e.g. XML, JSON.
+ * <p>
+ * This interface is not intended for use by applications, but rather only
+ * by the YANG runtime implementation.
+ * </p>
+ */
+public interface YangSerializer {
+
+    /**
+     * Returns the data format supported by this  serializer.
+     *
+     * @return supported data format
+     */
+    DataFormat supportsFormat();
+
+    /**
+     * Decodes the external representation of a configuration model from the
+     * specified input stream and into an in-memory representation.
+     *
+     * @param external input stream carrying external representation of
+     *                 configuration data
+     * @param context  serialization context containing information required
+     *                 for the serializer, e.g. access to model schemas
+     * @return in-memory representation of configuration data
+     */
+    DataNode decode(InputStream external, YangSerializerContext context);
+
+    /**
+     * Encodes the internal in-memory representation of a configuration model
+     * to an external representation consumable from the resulting input stream.
+     *
+     * @param internal in-memory representation of configuration data
+     * @param context  serialization context containing information required
+     *                 for the serializer, e.g. access to model schemas
+     * @return input stream carrying external representation of
+     * configuration data
+     */
+    InputStream encode(DataNode internal, YangSerializerContext context);
+
+}
diff --git a/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangSerializerContext.java b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangSerializerContext.java
new file mode 100644
index 0000000..dbc543e
--- /dev/null
+++ b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangSerializerContext.java
@@ -0,0 +1,27 @@
+/*
+ * 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.yang.runtime.api;
+
+/**
+ * Representation of a context for encoding and decoding YANG models via
+ * serializers.
+ */
+public interface YangSerializerContext {
+
+    // any required facilitites for serialization go here
+    //
+}
diff --git a/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangSerializerRegistry.java b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangSerializerRegistry.java
new file mode 100644
index 0000000..1d1b335
--- /dev/null
+++ b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/YangSerializerRegistry.java
@@ -0,0 +1,47 @@
+/*
+ * 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.yang.runtime.api;
+
+import java.util.Set;
+
+/**
+ * Registry of YANG serializers available as part of YANG runtime.
+ */
+public interface YangSerializerRegistry {
+
+    /**
+     * Registers a new serializer.
+     *
+     * @param serializer serializer to be registered
+     */
+    void registerSerializer(YangSerializer serializer);
+
+    /**
+     * Unregisters the specified serializer.
+     *
+     * @param serializer serializer to be unregistered
+     */
+    void unregisterSerializer(YangSerializer serializer);
+
+    /**
+     * Returns collection of all registered serializers.
+     *
+     * @return collection of serializers
+     */
+    Set<YangSerializer> getSerializers();
+
+}
diff --git a/runtime/api/src/main/java/org/onosproject/yang/runtime/api/package-info.java b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/package-info.java
new file mode 100644
index 0000000..5a0f954
--- /dev/null
+++ b/runtime/api/src/main/java/org/onosproject/yang/runtime/api/package-info.java
@@ -0,0 +1,20 @@
+/*
+ * 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.
+ */
+
+/**
+ * Set of facilities for processing and working with compiled YANG models.
+ */
+package org.onosproject.yang.runtime.api;
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