com.sun.faces.push.WebsocketFacesListener Maven / Gradle / Ivy
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package com.sun.faces.push;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import javax.faces.component.UIOutput;
import javax.faces.component.UIViewRoot;
import javax.faces.component.UIWebsocket;
import javax.faces.context.FacesContext;
import javax.faces.context.PartialViewContext;
import javax.faces.event.AbortProcessingException;
import javax.faces.event.ComponentSystemEvent;
import javax.faces.event.PostAddToViewEvent;
import javax.faces.event.PreRenderViewEvent;
import javax.faces.event.SystemEvent;
import javax.faces.event.SystemEventListener;
import javax.faces.push.Push;
/**
*
* This JSF listener for {@link UIViewRoot} ensures that the necessary JavaScript code to open or close the
* WebSocket is properly rendered depending on rendered and connected attributes.
*
* @author Bauke Scholtz
* @see Push
* @since 2.3
*/
public class WebsocketFacesListener implements SystemEventListener {
// Constants ------------------------------------------------------------------------------------------------------
private static final String SCRIPT_OPEN = "jsf.push.open('%s');";
private static final String SCRIPT_CLOSE = "jsf.push.close('%s');";
// Initialization -------------------------------------------------------------------------------------------------
public static void subscribeIfNecessary(FacesContext context) {
UIViewRoot view = context.getViewRoot();
List listeners = view.getListenersForEventClass(PostAddToViewEvent.class);
if (listeners == null || !listeners.stream().anyMatch(l -> l instanceof WebsocketFacesListener)) {
view.subscribeToViewEvent(PreRenderViewEvent.class, new WebsocketFacesListener());
}
}
public static boolean isNew(FacesContext context, UIWebsocket websocket) {
return getInitializedWebsockets(context).putIfAbsent(websocket.getClientId(context), websocket.isConnected()) == null;
}
// Actions --------------------------------------------------------------------------------------------------------
/**
* Only listens on {@link UIViewRoot}.
*/
@Override
public boolean isListenerForSource(Object source) {
return source instanceof UIViewRoot;
}
/**
* If the websocket has just switched its rendered or connected attribute, then
* render either the open() script or the close() script. During an ajax request with
* partial rendering, it's added as <eval> by partial response writer, else it's just added
* as a script component with target="body".
*/
@Override
public void processEvent(SystemEvent event) throws AbortProcessingException {
if (!(event instanceof PreRenderViewEvent)) {
return;
}
FacesContext context = ((ComponentSystemEvent) event).getFacesContext();
for (Entry initializedWebsocket : getInitializedWebsockets(context).entrySet()) {
String clientId = initializedWebsocket.getKey();
UIWebsocket websocket = (UIWebsocket) context.getViewRoot().findComponent(clientId);
boolean connected = websocket.isRendered() && websocket.isConnected();
boolean previouslyConnected = initializedWebsocket.setValue(connected);
if (previouslyConnected != connected) {
String script = String.format(connected ? SCRIPT_OPEN : SCRIPT_CLOSE, clientId);
PartialViewContext pvc = context.getPartialViewContext();
if (pvc.isAjaxRequest() && !pvc.isRenderAll()) {
context.getPartialViewContext().getEvalScripts().add(script);
}
else {
UIOutput outputScript = new UIOutput();
outputScript.setRendererType("javax.faces.resource.Script");
UIOutput content = new UIOutput();
content.setValue(script);
outputScript.getChildren().add(content);
context.getViewRoot().addComponentResource(context, outputScript, "body");
}
}
}
}
// Helpers --------------------------------------------------------------------------------------------------------
@SuppressWarnings("unchecked")
private static Map getInitializedWebsockets(FacesContext context) {
Map viewScope = context.getViewRoot().getViewMap();
Map initializedWebsockets = (Map) viewScope.get(WebsocketFacesListener.class.getName());
if (initializedWebsockets == null) {
initializedWebsockets = new HashMap<>();
viewScope.put(WebsocketFacesListener.class.getName(), initializedWebsockets);
}
return initializedWebsockets;
}
}