| /* |
| * 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); |
| } |
| |
| } |