Hello
I was trying to implement DWR reverse ajax in Liferay:
Here The following steps I have taken...
In a Custom Class mentioned in dwr.xml :package com.testing.Dwr;
import java.util.Date;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import org.directwebremoting.Browser;
import org.directwebremoting.ScriptSession;
import org.directwebremoting.ScriptSessionFilter;
import org.directwebremoting.ScriptSessions;
import org.directwebremoting.ServerContextFactory;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.impl.DaemonThreadFactory;
import org.directwebremoting.ui.dwr.Util;
public class TryDwr implements Runnable {
protected transient boolean active = false;
protected String timeString = "";
public TryDwr(){
ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1, new DaemonThreadFactory());
executor.scheduleAtFixedRate(this, 1, 50, TimeUnit.MILLISECONDS);
}
@Override
public void run() {
// TODO Auto-generated method stub
if (active)
{
String newTimeString = new Date().toString();
// We check this has not already been sent to avoid duplicate transmissions
if (!newTimeString.equals(timeString))
{
setClockDisplay(newTimeString);
timeString = newTimeString;
}
}
}
/**
* Called from the client to turn the clock on/off
*/
public synchronized void toggle()
{
active = !active;
setClockStatus();
}
private class UpdatesEnabledFilter implements ScriptSessionFilter
{
private String attrName;
public UpdatesEnabledFilter(String attrName)
{
this.attrName = attrName;
}
public boolean match(ScriptSession ss)
{
Object check = ss.getAttribute(attrName);
return (check != null && check.equals(Boolean.TRUE));
}
}
/**
* Send the time String to clients that have an UPDATES_ENABLED_ATTR attribute set to true
* on their ScriptSession.
*
* @param output The string to display.
*/
public void setClockDisplay(final String output)
{
Browser.withAllSessionsFiltered(new UpdatesEnabledFilter(UPDATES_ENABLED_ATTR), new Runnable()
{
public void run()
{
Util.setValue("clockDisplay", output);
}
});
}
/**
* Call a function on the client for each ScriptSession.
* passing the clock's status for display.
*
* @param output The string to display.
*/
public void setClockStatus()
{
Browser.withAllSessions(new Runnable()
{
public void run()
{
ScriptSessions.addFunctionCall("setClockStatus()", active);
}
});
}
public void setEnabledAttribute(Boolean enabled) {
ScriptSession scriptSession = WebContextFactory.get().getScriptSession();
scriptSession.setAttribute(UPDATES_ENABLED_ATTR, enabled);
}
private static String UPDATES_ENABLED_ATTR = "UPDATES_ENABLED";
}
An empty Portlet ClassI will customize it later with ajax request, this is empty as its a Demo for now...
JSP view.jsp<%@ taglib uri="http://java.sun.com/portlet_2_0" prefix="portlet" %>
<portlet:defineobjects />
This is the <b>Dwr Check</b> portlet in View mode.
<script>
window.onload=function()
{
dwr.engine.setActiveReverseAjax(true);
dwr.engine.setErrorHandler(errorHandler);
dwr.engine.setPollStatusHandler(updatePollStatus);
updatePollStatus(true);
Tabs.init('tabList', 'tabContents');
}
function errorHandler(message, ex)
{
dwr.util.setValue("error", "Cannot connect to server. Initializing retry logic.", {escapeHtml:false});
setTimeout(function() { dwr.util.setValue("error", ""); }, 5000)
}
function updatePollStatus(pollStatus)
{
dwr.util.setValue("pollStatus", pollStatus ? "Online" : "Offline", {escapeHtml:false});
}
function enableUpdates(enabled)
{
if (!enabled)
{
dwr.util.setValue("clockDisplay", "This tab/window does not have updates enabled.");
}
Clock.setEnabledAttribute(enabled);
}
function setClockStatus(clockStatus) {
dwr.util.setValue("clockStatus", clockStatus ? "Clock started" : "Clock stopped");
}
</script>
<div id="demoDiv">
<input type="button" value="Start / Stop" onclick="Clock.toggle();">
Server status: <span id="pollStatus"></span>
<div id="error"></div>
<p></p>
<h2 id="clockDisplay"></h2>
</div>
<div>
<h3>Filtering</h3>
<input type="button" value="Enable Updates" onclick="enableUpdates(true);">
<input type="button" value="Disable Updates" onclick="enableUpdates(false);">
</div>
Its not giving any error, But I doesn't enable clockDisplay.....P.S. Codes are copied from DWR website just to understand mechanism. And implement in Liferay.....
Please suggest, I am new in Liferay, browsed in internet to find any solution. i also read through documentations.
BR
Arko
