Push can be controlled by a programmatic API. However a durable topic still needs to be created and registered in both RichFaces and the Java Messaging Service.
The programmatic API consists of a TopicKey which addresses the topic, and a TopicsContext which is used for publishing messages.
For the purpose of observing events from the server, the client creates a permanent connection to the server either by using a WebSocket connection or the long-polling method. Permanent connections are managed by the Atmosphere Framework.
In this example, the message doesn't contain any data - it instructs the client to re-render part of the page. In this case it forces the client to load new unique ID.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <ui:composition xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:a4j="http://richfaces.org/a4j" xmlns:rich="http://richfaces.org/rich"> <h:form> <a4j:push id="pushJms" address="pushTopicsContext"> <a4j:ajax event="dataavailable" render="uuid" /> </a4j:push> <h:panelGrid columns="2"> <h:outputLabel value="New UUID:" /> <a4j:outputPanel id="uuid" layout="block"> #{pushBean.UUID} </a4j:outputPanel> </h:panelGrid> </h:form> </ui:composition>
/** * JBoss, Home of Professional Open Source. * Copyright 2010, Red Hat, Inc., and individual contributors * as indicated by the @author tags. See the copyright.txt file in the * distribution for a full listing of individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ package org.richfaces.demo.push; import org.richfaces.application.push.TopicKey; import org.richfaces.application.push.TopicsContext; import org.richfaces.log.Logger; import org.richfaces.log.RichfacesLogger; /** * Sends message to topic using TopicsContext. * * @author <a href="http://community.jboss.org/people/lfryc">Lukas Fryc</a> */ public class TopicsContextMessageProducer implements MessageProducer { public static final String PUSH_TOPICS_CONTEXT_TOPIC = "pushTopicsContext"; private Logger log = RichfacesLogger.WEBAPP.getLogger(); /* * (non-Javadoc) * * @see org.richfaces.demo.push.MessageProducer#sendMessage() */ public void sendMessage() throws Exception { try { TopicKey topicKey = new TopicKey(PUSH_TOPICS_CONTEXT_TOPIC); TopicsContext topicsContext = TopicsContext.lookup(); topicsContext.publish(topicKey, "message"); } catch (Exception e) { log.info("Sending push message using TopicContext failed (" + e.getMessage() + ") - the JMS subsystem might not be ready yet - operation will be repeated in few seconds"); if (log.isDebugEnabled()) { log.debug(e); } } } /* * (non-Javadoc) * * @see org.richfaces.demo.push.MessageProducer#getInterval() */ public int getInterval() { return 5000; } /* * (non-Javadoc) * * @see org.richfaces.demo.push.MessageProducer#finalizeProducer() */ public void finalizeProducer() { } }
