Sketching out basis for network configuration subsystem API.

Change-Id: I9d56a8392bd300566fb333607102cc965b2fa66e

+/*
+ * Copyright 2015 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.exp.net.config;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Base abstraction of a configuration facade for a specific subject. Derived
+ * classes should keep all state in the specified JSON tree.
+ *
+ * @param <S> type of subject
+ */
+public abstract class Config<S> {
+
+    protected ObjectMapper mapper;
+    protected ObjectNode node;
+    private S subject;
+    private ConfigApplyDelegate<S> delegate;
+
+    /**
+     * Returns the specific subject to which this configuration pertains.
+     *
+     * @return configuration subject
+     */
+    S subject() {
+        return subject;
+    }
+
+    /**
+     * Initializes the configuration behaviour with necessary context.
+     *
+     * @param subject configuration subject
+     * @param node    JSON object node where configuration data is stored
+     * @param mapper  JSON object mapper
+     */
+    public void init(S subject, ObjectNode node, ObjectMapper mapper,
+                     ConfigApplyDelegate<S> delegate) {
+        this.subject = checkNotNull(subject);
+        this.node = checkNotNull(node);
+        this.mapper = checkNotNull(mapper);
+        this.delegate = checkNotNull(delegate);
+    }
+
+    /**
+     * Applies any configuration changes made via this configuration.
+     */
+    public void apply() {
+        delegate.onApply(this);
+    }
+
+}

+/*
+ * Copyright 2015 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.exp.net.config;
+
+/**
+ * Delegate for notification when configuration changes have been applied.
+ */
+public interface ConfigApplyDelegate<S> {
+
+    /**
+     * Processes changes applied to the specified configuration.
+     *
+     * @param config changed configuration
+     */
+    void onApply(Config<S> config);
+
+}

+/*
+ * Copyright 2015 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.exp.net.config;
+
+
+/**
+ * Base abstract factory for creating configurations for the specified subject type.
+ *
+ * @param <S> subject class
+ */
+public abstract class ConfigFactory<S> {
+
+    private final Class<S> subjectClass;
+    private final String key;
+
+    /**
+     * Creates a new configuration factory for the specified class of subjects
+     * and bound to the given subject configuration key.
+     *
+     * @param subjectClass subject class
+     * @param key          subject configuration key
+     */
+    protected ConfigFactory(Class<S> subjectClass, String key) {
+        this.subjectClass = subjectClass;
+        this.key = key;
+    }
+
+    /**
+     * Returns the class of the subject to which this factory applies.
+     *
+     * @return subject type
+     */
+    public Class<S> subjectClass() {
+        return subjectClass;
+    }
+
+    /**
+     * Returns the key to which produced configurations should be bound.
+     *
+     * @return subject configuration key
+     */
+    public String key() {
+        return key;
+    }
+
+    /**
+     * Creates a new but uninitialized configuration. Framework will initialize
+     * the configuration via {@link Config#init} method.
+     *
+     * @return new uninitialized configuration
+     */
+    public abstract Config<S> createConfig();
+
+}

+/*
+ * Copyright 2015 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.exp.net.config;
+
+import java.util.Set;
+
+/**
+ * Service for tracking network configuration factories.
+ */
+public interface NetworkConfigRegistry {
+
+    /**
+     * Registers the specified configuration factory.
+     *
+     * @param configFactory configuration factory
+     */
+    void registerConfigFactory(ConfigFactory configFactory);
+
+    /**
+     * Unregisters the specified configuration factory.
+     *
+     * @param configFactory configuration factory
+     */
+    void unregisterConfigFactory(ConfigFactory configFactory);
+
+    /**
+     * Returns set of configuration factories available for the specified
+     * class of subject.
+     *
+     * @param subjectClass subject class
+     */
+    <T> Set<ConfigFactory<T>> getConfigFactories(Class<T> subjectClass);
+
+    /**
+     * Returns the configuration type registered for the specified
+     * subject type and key.
+     *
+     * @param subjectClass subject class
+     */
+    <T> ConfigFactory<T> getConfigFactory(Class<T> subjectClass, String configKey);
+
+    /**
+     * Returns the configuration type registered for the specified
+     * configuration class.
+     *
+     * @param configClass configuration class
+     */
+    <T> ConfigFactory<T> getConfigFactory(Class<Config<T>> configClass);
+
+}

+/*
+ * Copyright 2015 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.exp.net.config;
+
+import java.util.Set;
+
+/**
+ * Service for tracking network configurations which specify how the discovered
+ * network information should be interpretted and how the network should be
+ * configured.
+ */
+public interface NetworkConfigService {
+
+    /**
+     * Returns the set of subjects for which some configuration is available.
+     *
+     * @param subjectClass subject class
+     * @return set of configured subjects
+     */
+    <T> Set<T> getSubjects(Class<T> subjectClass);
+
+    /**
+     * Returns the set of subjects for which the specified configuration is
+     * available.
+     *
+     * @param subjectClass subject class
+     * @param configClass  configuration class
+     * @return set of configured subjects
+     */
+    <T> Set<T> getSubjects(Class<T> subjectClass, Class<Config<T>> configClass);
+
+
+    /**
+     * Returns all configurations for the specified subject.
+     *
+     * @param subject configuration subject
+     * @return set of configurations
+     */
+    <T> Set<Config<T>> getConfigs(T subject);
+
+    /**
+     * Returns the configuration for the specified subject and configuration
+     * class if one is available; null otherwise.
+     *
+     * @param subject     configuration subject
+     * @param configClass configuration class
+     * @return configuration or null if one is not available
+     */
+    <T> Config<T> getConfig(T subject, Class<Config<T>> configClass);
+
+}

+/*
+ * Copyright 2015 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.
+ */
+
+/**
+ * Subsystem for tracking network environment configuration.
+ */
+package org.onosproject.exp.net.config;
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