GUI -- Rename UIMessageHandlerTwo => UIMessageHandler. Also, make bindHandlers() private.
Change-Id: Id36e220c1285b88b8b4db0e106ef063bd8b9bfd1
diff --git a/core/api/src/main/java/org/onosproject/ui/UiMessageHandler.java b/core/api/src/main/java/org/onosproject/ui/UiMessageHandler.java
new file mode 100644
index 0000000..2f70780
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/ui/UiMessageHandler.java
@@ -0,0 +1,166 @@
+/*
+ * 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.ui;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onlab.osgi.ServiceDirectory;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Abstraction of an entity capable of processing a JSON message from the user
+ * interface client.
+ * <p>
+ * The message is a JSON object with the following structure:
+ * </p>
+ * <pre>
+ * {
+ * "type": "<em>event-type</em>",
+ * "sid": "<em>sequence-number</em>",
+ * "payload": {
+ * <em>arbitrary JSON object structure</em>
+ * }
+ * }
+ * </pre>
+ */
+public abstract class UiMessageHandler {
+
+ private final Map<String, RequestHandler> handlerMap = new HashMap<>();
+
+ private UiConnection connection;
+ private ServiceDirectory directory;
+
+ /**
+ * Mapper for creating ObjectNodes and ArrayNodes etc.
+ */
+ protected final ObjectMapper mapper = new ObjectMapper();
+
+
+ /**
+ * Subclasses must return the collection of handlers for the
+ * message types they handle.
+ *
+ * @return the message handler instances
+ */
+ protected abstract Collection<RequestHandler> getHandlers();
+
+ /**
+ * Returns the set of message types which this handler is capable of
+ * processing.
+ *
+ * @return set of message types
+ */
+ public Set<String> messageTypes() {
+ return Collections.unmodifiableSet(handlerMap.keySet());
+ }
+
+ /**
+ * Processes a JSON message from the user interface client.
+ *
+ * @param message JSON message
+ */
+ public void process(ObjectNode message) {
+ String type = JsonUtils.eventType(message);
+ long sid = JsonUtils.sid(message);
+ ObjectNode payload = JsonUtils.payload(message);
+ exec(type, sid, payload);
+ }
+
+ /**
+ * Finds the appropriate handler and executes the process method.
+ *
+ * @param eventType event type
+ * @param sid sequence identifier
+ * @param payload message payload
+ */
+ void exec(String eventType, long sid, ObjectNode payload) {
+ RequestHandler handler = handlerMap.get(eventType);
+ if (handler != null) {
+ handler.process(sid, payload);
+ }
+ }
+
+ private void bindHandlers() {
+ Collection<RequestHandler> handlers = getHandlers();
+ checkNotNull(handlers, "Handlers cannot be null");
+ checkArgument(!handlers.isEmpty(), "Handlers cannot be empty");
+
+ for (RequestHandler h : handlers) {
+ h.setParent(this);
+ handlerMap.put(h.eventType(), h);
+ }
+ }
+
+ /**
+ * Initializes the handler with the user interface connection and
+ * service directory context.
+ *
+ * @param connection user interface connection
+ * @param directory service directory
+ */
+ public void init(UiConnection connection, ServiceDirectory directory) {
+ this.connection = connection;
+ this.directory = directory;
+ bindHandlers();
+ }
+
+ /**
+ * Destroys the message handler context.
+ */
+ public void destroy() {
+ this.connection = null;
+ this.directory = null;
+ }
+
+ /**
+ * Returns the user interface connection with which this handler was primed.
+ *
+ * @return user interface connection
+ */
+ public UiConnection connection() {
+ return connection;
+ }
+
+ /**
+ * Returns the user interface connection with which this handler was primed.
+ *
+ * @return user interface connection
+ */
+ public ServiceDirectory directory() {
+ return directory;
+ }
+
+ /**
+ * Returns implementation of the specified service class.
+ *
+ * @param serviceClass service class
+ * @param <T> type of service
+ * @return implementation class
+ * @throws org.onlab.osgi.ServiceNotFoundException if no implementation found
+ */
+ protected <T> T get(Class<T> serviceClass) {
+ return directory.get(serviceClass);
+ }
+
+}