Great, lots to play with :)
Before I look into writing my own JSNI bridge, I've still been trying
to use gwt-exporter, but.....
I've three GWT applications:-
(1) Plugin (inherits "Common")
(2) Backend (inherits "Common")
(3) Common
"Plugin"
--------
Contains:-
...
echoButton.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
//Debugging statements shown --> shows 'callback' is not null
PluginCallback<String> callback = getPluginCallback();
Window.alert("Plugin.onModuleLoad.onClick.callback is " +
(callback != null ? "not " : "") + "null");
echo(text.getText(), callback);
}
});
...
private native void echo(String text, PluginCallback<String>
callback) /*-{
//Debugging statements shown --> shows 'callback' is not null
alert("Plugin.echo.callback is " + (callback != null ? "not " :
"") + "null");
$wnd.com.anstis.pluginserver.CommonService.echo(text, callback);
}-*/;
"Backend"
--------
Contains:-
public void onModuleLoad() {
//Use gwt-exporter to generate the JSNI for CommonService.class
GWT.create(CommonService.class);
}
CommonService is:-
@Export
public class CommonService implements Exportable {
private static final EchoServiceAsync echoService =
GWT.create(EchoService.class);
public static void echo(String input, PluginCallback<String>
callback) {
//Debugging statements shown --> shows 'callback' is null
Window.alert("CommonService.echo.callback is " + (callback !=
null ? "not " : "") + "null");
try {
//The guts of the method, invoke a GWT-RPC call --> RTE, as
'callback' is null
echoService.echo(input, callback);
} catch (Exception e) {
e.fillInStackTrace();
e.printStackTrace(System.out);
Window.alert(e.getMessage());
}
}
}
"Common"
--------
Simply defines PluginCallback, as follows:-
public class PluginCallback<T> implements AsyncCallback<T> {
public void onFailure(Throwable caught) {}
public void onSuccess(T result) {}
}
My problem is that the PluginCallback instance is proven to be non-
null in "Plugin" (both Java and JSNI methods), but is reported as null
in "Backends" CommonService.
Somewhere it is getting munged, but I only pass a Java Object from
"Plugin" to JSNI (echo) to Java (CommonService) so don't understand
why it's being nulled?!?!
Any ideas (I'll post as a new question if you don't see anything
wrong, so it gets seen by a new audience as opposed to those just
following this thread).
Thanks,
Mike
On Jun 21, 7:32 pm, lemaiol <[email protected]> wrote:
> Hi Mike,
>
> > I am growing to believe I need to deploy each plug-in as a separate
> > WAR on a web-server. Is this true, or have I missed something?
>
> In the case of my architecture, it is even a requirement that every
> plugin will be deployed as an own WAR file. It allows different teams
> working in parallel in completely independent applications (plugins)
> which have a common "message data model". When inside the plugins
> container, they receive messages with this "common data model". When
> out of the plugins container, the show a simplified UI to let the
> developer pass a "message" generated by hand and therefore test the
> application.
>
> > I am also using gwt-exporter to make the JSNI messaging mechanism;
> > i.e. I just write an "Exportable" class and use the resulting JS API
> > from my plugins. I am hoping to use gwt-api-interop to remove the need
> > to use the JS API.
>
> I have seen gwt-exporter but do not know gwt-api-interop.
>
> > I assume the JS "bridge" between GWT applications handles the
> > messaging between them (i.e. plugins register callbacks to handle
> > messages sent from the "host"?)
>
> Yes.
>
> > If I understand correctly, adding additional script tags to my
> > "loader" page and having each plug-in as a separate WAR I avoid the
> > need to inherit in my gwt.xml file?
>
> My common model and plugin base classes live in a common GWT module
> that each plugin inherits.
>
> > An example of your use of JavaScriptObject in your messaging sub-
> > system would be interesting....
>
> // Application specific common model
> public final class CustomerInfo extends ModuleInfo {
> protected CustomerInfo() {
> }
>
> public native String getId() /*-{
> return this.id;
> }-*/;
>
> public native void setId(String id) /*-{
> this.id = id;
> }-*/;
>
> }
>
> // Base class for common models - no functionality as of now
> public class ModuleInfo extends JavaScriptObject {
> protected ModuleInfo() {
> }
>
> }
>
> // To be implemented by every module
> public interface IModule<T extends ModuleInfo> {
> public String getName();
> public void dispatch(String containerId, T moduleInfo);
>
> }
>
> // To be implemented by the main module or classes interested in
> module lifecycle events
> public interface IModuleAware<T extends ModuleInfo> {
> public void onModuleAttached(Module<T> module);
>
> }
>
> // Durable callback implementation - Because it uses JSNI, can be
> inherited from GWT modules but it is interoperable. Avoids using gwt-
> exporter
> public final class ModuleListener<T extends ModuleInfo> extends
> JavaScriptObject {
> protected ModuleListener() {
> }
>
> public void onModuleAttached(Module<T> module) {
> invokeCallback(getCallback(), module);
> }
>
> private native void invokeCallback(JavaScriptObject callback,
> Module<T> module) /*-{
> this.callback(module);
> }-*/;
>
> private native JavaScriptObject getCallback() /*-{
> return this.callback;
> }-*/;
>
> public native void setCallback(JavaScriptObject callback) /*-{
> this.callback = callback;
> }-*/;
>
> }
>
> // Support for common modules functionality (static methods)
> public abstract class ModulesSupport {
> public static <T extends ModuleInfo> boolean
> registerAsListener(IModuleAware<T> instance) {
> ModulesConfig<T> modulesConfig = getModulesConfig();
> boolean result = null != modulesConfig;
> if (result) {
> modulesConfig.registerListener(createListener(instance));
> }
> return result;
> }
>
> public static <T extends ModuleInfo> boolean
> registerAsModule(IModule<T> module) {
> ModulesConfig modulesConfig = ModulesConfig.get();
> boolean result = null != modulesConfig;
> if (result) {
> modulesConfig.attach(module.getName(),
> createDispatchCallback(module));
> }
> return result;
> }
>
> public static <T extends ModuleInfo> ModulesConfig<T>
> getModulesConfig() {
> return ModulesConfig.get();
> }
>
> private static <T extends ModuleInfo> ModuleListener<T>
> createListener(IModuleAware<T> instance) {
> ModuleListener<T> result =
> JavaScriptObject.createObject().cast();
> result.setCallback(createListenerCallback(instance));
> return result;
> }
>
> private static native JavaScriptObject
> createListenerCallback(IModuleAware instance) /*-{
> return function(module) {
>
> [email protected]::onModuleAttached(Lorg/
> myexample/modules/client/Module;)(module);
> };
> }-*/;
>
> private static native JavaScriptObject
> createDispatchCallback(IModule instance) /*-{
> return function(containerId, moduleInfo) {
>
> [email protected]::dispatch(Ljava/lang/
> String;Lorg/myexample/modules/client/ModuleInfo;)(containerId,
> moduleInfo);
> };
> }-*/;
>
> }
>
> Hope it helps,
> Berto
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