Multiple DWR classes in web.xml (using annotations) - ajax

Question

i want to use annotated DWR classes in my project. So i created 2 classes.
Assume Dwr1.java & Dwr2.java
in my web.xml i have the following entry to load the classes:
<servlet>
<display-name>DWR Servlet</display-name>
<servlet-name>dwr-invoker</servlet-name>
<servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>activeReverseAjaxEnabled</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>classes</param-name>
<param-value>
de.package.Dwr1,
de.another.package.Dwr2
</param-value>
</init-param>
<load-on-startup>3</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dwr-invoker</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
The Proplem is that the Dwr2 Class does not get instantiated. If i remove Dwr1 from my web.xml, Dwr2 gets instantiated. But if i have both entries in my web.xml only Dwr1 gets instantiated.
Dwr1 is a very simple class:
#RemoteProxy
public class Dwr1 {
#RemoteMethod
public String getString(String key) {
return Util.GetString(key);
}
}
Dwr2 is a little bit more complex like:
#RemoteProxy
public class Dwr2 {
#RemoteMethod
public Dwr2() {
ServerUtil.registerOnFE(new UpdateClient());
}
private void updateBrowser(final String arg) {
Browser.withPage("/page.do", new Runnable() {
#Override
public void run() {
ScriptSessions.addFunctionCall("update", arg);
}
});
}
private class UpdateClient {
#Override
onRecieveUpdate(String arg) {
updateBrowser(arg);
}
}
}
Are there any Mistakes in my classes or in my web.xml? Or how can i instantiate multiple DWR Classes with Annotations?

Answer 1

I found a solution to fix this issue. It seems like DWR doesn´t instantiate every class on the server-startup. (But it apparently does if there is only one class defined in the config file). However, I just implemented a "dummy-method" in dwr-classes, called "start()". The Method does nothing, but when it get's called from javascript, the class gets instantiated. My solution looks like this:
<servlet>
<display-name>DWR Servlet</display-name>
<servlet-name>dwr-invoker</servlet-name>
<servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>activeReverseAjaxEnabled</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>classes</param-name>
<param-value>
de.package.Dwr1,
de.another.package.Dwr2
</param-value>
</init-param>
<load-on-startup>3</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dwr-invoker</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
Dwr1
#RemoteProxy
public class Dwr1 {
#RemoteMethod
public String getString(String key) {
return Util.GetString(key);
}
}
Dwr2
#RemoteProxy
public class Dwr2 {
public Dwr2() {
ServerUtil.registerOnFE(new UpdateClient());
}
#RemoteMethod
public void start() {
//Do nothing
}
private void updateBrowser(final String arg) {
Browser.withPage("/page.do", new Runnable() {
#Override
public void run() {
ScriptSessions.addFunctionCall("update", arg);
}
});
}
private class UpdateClient {
#Override
onRecieveUpdate(String arg) {
updateBrowser(arg);
}
}
}
A call of the start()-method of Dwr2 class triggers the insantiation of it.