ONOS checkin based on commit tag e796610b1f721d02f9b0e213cf6f7790c10ecd60

Change-Id: Ife8810491034fe7becdba75dda20de4267bd15cd

1 files changed, 142 insertions, 0 deletions

diff --git a/framework/src/onos/core/api/src/main/java/org/onosproject/ui/RequestHandler.java b/framework/src/onos/core/api/src/main/java/org/onosproject/ui/RequestHandler.java
new file mode 100644
index 00000000..1678923d
--- /dev/null
+++ b/framework/src/onos/core/api/src/main/java/org/onosproject/ui/RequestHandler.java
@@ -0,0 +1,142 @@
+/*
+ * 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;
+
+/**
+ * Abstraction of an entity that handles a specific request from the
+ * user interface client.
+ *
+ * @see UiMessageHandler
+ */
+public abstract class RequestHandler {
+
+    protected static final ObjectMapper MAPPER = new ObjectMapper();
+
+    private final String eventType;
+    private UiMessageHandler parent;
+
+
+    public RequestHandler(String eventType) {
+        this.eventType = eventType;
+    }
+
+    // package private
+    void setParent(UiMessageHandler parent) {
+        this.parent = parent;
+    }
+
+    /**
+     * Returns the event type that this handler handles.
+     *
+     * @return event type
+     */
+    public String eventType() {
+        return eventType;
+    }
+
+    /**
+     * Processes the incoming message payload from the client.
+     *
+     * @param sid message sequence identifier
+     * @param payload request message payload
+     */
+    // TODO: remove sid from signature
+    public abstract void process(long sid, ObjectNode payload);
+
+
+
+    // ===================================================================
+    // === Convenience methods...
+
+    /**
+     * 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 parent.directory().get(serviceClass);
+    }
+
+    /**
+     * Sends a message back to the client.
+     *
+     * @param eventType message event type
+     * @param sid       message sequence identifier
+     * @param payload   message payload
+     */
+    // TODO: remove sid from signature
+    protected void sendMessage(String eventType, long sid, ObjectNode payload) {
+        parent.connection().sendMessage(eventType, sid, payload);
+    }
+
+    /**
+     * Sends a message back to the client.
+     * Here, the message is preformatted; the assumption is it has its
+     * eventType, sid and payload attributes already filled in.
+     *
+     * @param message the message to send
+     */
+    protected void sendMessage(ObjectNode message) {
+        parent.connection().sendMessage(message);
+    }
+
+    /**
+     * Allows one request handler to pass the event on to another for
+     * further processing.
+     * Note that the message handlers must be defined in the same parent.
+     *
+     * @param eventType event type
+     * @param sid       sequence identifier
+     * @param payload   message payload
+     */
+    // TODO: remove sid from signature
+    protected void chain(String eventType, long sid, ObjectNode payload) {
+        parent.exec(eventType, sid, payload);
+    }
+
+    // ===================================================================
+
+
+    /**
+     * Returns the specified node property as a string.
+     *
+     * @param node message event
+     * @param key property name
+     * @return property as a string
+     */
+    protected String string(ObjectNode node, String key) {
+        return JsonUtils.string(node, key);
+    }
+
+    /**
+     * Returns the specified node property as a string, with a default fallback.
+     *
+     * @param node         object node
+     * @param key          property name
+     * @param defValue     fallback value if property is absent
+     * @return property as a string
+     */
+    protected String string(ObjectNode node, String key, String defValue) {
+        return JsonUtils.string(node, key, defValue);
+    }
+
+}