Java tutorial
/* Copyright [2011] [Vaadin Ltd] 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.vaadin.dontpush.widgetset.client; import com.google.gwt.core.client.GWT; import com.google.gwt.http.client.URL; import com.google.gwt.user.client.Cookies; import com.google.gwt.user.client.Window; import com.vaadin.terminal.gwt.client.ApplicationConfiguration; import com.vaadin.terminal.gwt.client.ApplicationConnection; import com.vaadin.terminal.gwt.client.BrowserInfo; import com.vaadin.terminal.gwt.client.VConsole; import com.vaadin.terminal.gwt.client.ValueMap; import com.vaadin.terminal.gwt.client.WidgetSet; import java.io.Serializable; import java.util.Date; import java.util.List; import org.atmosphere.gwt.client.AtmosphereClient; import org.atmosphere.gwt.client.AtmosphereListener; /** * Uses WebSockets instead of XHR's for communicating with server. * * @author mattitahvonen */ public class SocketApplicationConnection extends ApplicationConnection { private AtmosphereClient ws; private boolean ownRequestPending; private AtmosphereListener _cb = new AtmosphereListener() { StringBuilder msg = new StringBuilder(); boolean msgOpen; public void onConnected(int heartbeat, int connectionID) { VConsole.log("WS Connected"); if (!applicationRunning) { repaintAll(); } else if (visitServerOnConnect) { // reconnecting, ensure we get sane answers and up to date state sendPendingVariableChanges(); } else { getConnectionGuard().connected(); } } public void onBeforeDisconnected() { VConsole.log("DEBUG: onbeforediconnected"); } public void onDisconnected() { VConsole.log("WS Disconnected"); // reconnect is automatic // TODO I guess this should be configurable for different use cases // TODO how to handle windows forgotten open ? getConnectionGuard().disconnected(); } public void onError(Throwable exception, boolean connected) { VConsole.log("DEBUG: onError"); VConsole.log(exception); getConnectionGuard().errorOccured(); } public void onHeartbeat() { VConsole.log("DEBUG: onHeartbeat"); } public void onRefresh() { VConsole.log("DEBUG: onRefresh"); } public void onMessage(List<? extends Serializable> messages) { for (Serializable serializable : messages) { String message = serializable.toString(); VConsole.log("message"); final Date start = new Date(); if (!msgOpen) { msg.append("{"); msgOpen = true; } boolean terminated = message.endsWith("OZONEEND"); if (terminated) { message = message.substring(0, message.length() - "OZONEEND".length()); } msg.append(message); if (terminated) { if (!ownRequestPending) { startRequest(); VConsole.log("Changeset pushed by the server"); } // TODO add some sort of sequence number so we could check // whether this was really anwer to out request or message // pushed by server ownRequestPending = false; msg.append("}"); message = msg.toString(); msg = new StringBuilder(); msgOpen = false; try { VConsole.log("Received socket message..."); ValueMap json = evaluateUIDL(message); if (applicationRunning) { handleUIDLMessage(start, message, json); } else { applicationRunning = true; handleWhenCSSLoaded(message, json); ApplicationConfiguration.startNextApplication(); } getConnectionGuard().responseHandled(); } catch (Exception e) { VConsole.log("Received socket message, but parsing failed!"); VConsole.log(message); VConsole.log(e); getConnectionGuard().parsingErrorOccured(); } } } } }; private ConnectionGuard errorDisplay; private boolean visitServerOnConnect; @Override public void init(WidgetSet widgetSet, ApplicationConfiguration cnf) { super.init(widgetSet, cnf); // First opening of WS will repaint all -> start the app getWebSocket(); } private ConnectionGuard getConnectionGuard() { if (errorDisplay == null) { errorDisplay = GWT.create(ConnectionGuard.class); errorDisplay.setSocketApplicationConnection(this); } return errorDisplay; } private AtmosphereClient getWebSocket() { if (this.ws == null) { // if timed out or not started, create websocket to server String url = getConfiguration().getApplicationUri() + "UIDL/"; if (url.startsWith("/")) { String hostPageBaseURL = GWT.getHostPageBaseURL(); String[] split = hostPageBaseURL.split("\\/\\/"); String host = split[1].substring(0, split[1].indexOf("/")); String protoAndHost = split[0] + "//" + host; url = protoAndHost + url; } String cmid = Cookies.getCookie("OZONE_CM_ID"); url += cmid + "/" + getConfiguration().getInitialWindowName(); VConsole.log(url); boolean tryWithWebsockets = BrowserInfo.get().isWebkit(); VConsole.log("Creating atmosphere client..."); /* * Ask atmosphere guys to fix this. Automatic degrading from * websockets don't work in others but webkit. */ this.ws = new AtmosphereClient(url, null, _cb, tryWithWebsockets); VConsole.log("...starting..."); this.ws.start(); } return this.ws; } @Override public void start() { VConsole.log("No real start here"); /* * NOP, init when web sockect connected */ } @Override protected void makeUidlRequest(String requestData, String extraParams, boolean forceSync) { if (visitServerOnConnect) { // TODO atmosphere should keep track of unsent changes for us ? GWT // atmosphere or our usage issue? Now repainting to make sure state // is in sync, but that may be bit expensive in some cases. visitServerOnConnect = false; extraParams = "repaintAll=1"; } VConsole.log("->SERVER: " + requestData + "; p: " + extraParams + "; forceSync: " + forceSync); // Due to atmosphere bug/feature/whatever we need to urlencode the // payload as well (linebreaks are not allowed in messages) requestData = URL.encode(requestData); if (forceSync) { /* * TODO Check if this really works. Else we could send the last * "window close event" with synchronous xhr. */ getWebSocket().broadcast(extraParams + "#" + requestData); } else { startRequest(); this.ownRequestPending = true; getConnectionGuard().expectResponse(); getWebSocket().broadcast(extraParams + "#" + requestData); } } private static native ValueMap evaluateUIDL(String jsonText) /*-{ try { return JSON.parse(jsonText); } catch(ignored) { return eval('(' + jsonText + ')'); } }-*/; public void goOffline() { ws.stop(); if (ownRequestPending) { endRequest(); ownRequestPending = false; } } public void reconnect() { visitServerOnConnect = true; ws.start(); } public void restart() { String appUri = getAppUri() + "?restartApplication"; Window.Location.replace(appUri); } @Override public void sendPendingVariableChanges() { // leave stuff in queue if no active connection if (applicationRunning && ws != null && ws.isRunning()) { super.sendPendingVariableChanges(); } } }