I need implement a system with multithreat in GWT.
What is the best way to do this???
I am using http request, json
and web service building in php
Thanks
GWT code is translated to JavaScript which is not multithreaded (or at least, not in a way accessible to the user).
There are ways to program around tasks and callbacks in GWT. Take a look at the Scheduler class.
Related
I have a Dart project want to reuse the existing GWT service (RemoteServiceServlet), any way can do this?
There is no special support for GWT-RPC included in Dart and there seem to be no 3rd-Party apps available that provide this functionality.
This question is similar (but not Dart)
GWT Data Serialization
If you're feeling ambitious, you can write a Dart client that understand the GWT-RPC wire-protocol and use that to communicate. This is likely to be a great deal of work however.
I had a similar situation where I needed to access GWT-RPC Services from a non-GWT client (it was JavaScript, not Dart, but the same concept applies). Instead of accessing the GWT-RPC service directly, I ended up using jsonrpc4j to setup a JSON-RPC service alongside GWT-RPC. I was able to point jsonrpc4j at the GWT services to use, so there was no code duplication, just the extra code needed to wire up the JSON-RPC.
Then you will need a Dart JSON-RPC client, of which there are a few available: jsonrpc, jsonrpc2.
This all assumes that you have access to the GWT server and can setup the JSON-RPC service.
I have my restful CXF service producing JSON with default JSON provider. I want to know if we can use GWT to build client which will user the restful service. Will it work ? If not, what would be a simple work around for this type ?
Thank you.
regards
It will work. See this. Here's a quote:
GWT does not limit you to this one RPC mechanism or server side development environment. You are free to integrate with other RPC mechanisms, such as JSON using the GWT supplied RequestBuilder class, JSNI methods or a third party library.
Is it possible to write a server side of GWT application in other languages then Java if yes how to use GWT-RPC mechanism, an sample code please
Thanks
Please read the GWT documentation Communication with the Server:
If you can run Java on the backend and are creating an interface for your application's server-side business logic, GWT RPC is probably your best choice. [...]
If your application talks to a server that cannot host Java servlets, or one that already uses another data format like JSON or XML, you can make HTTP requests to retrieve the data.
You can write your server in any language you choose, GWT is just JavaScript to be run in your users' browsers.
If you decide to go that route, you should look into using RequestFactory to communicate with your server instead of GWT-RPC, which is Java-specific. RequestFactory uses standard JSON, which any language can read/write.
Dont waist your time with GWT-RPC. It's bad. Use RequestFactory. I am surprised people are promoting GWT-RPC. It's a broken toy.
I am developing an application in GWT which needs to call a native C++ code in Directshow to do some multimedia processing.I am guessing that I cant use JNI because GWT converts code to javascript.I did have a look at similar posts on the forum(and on GWT site about JSNI) but cant find a example that specifically talks about calling C++ code from GWT(its mostly about calling Java code from Javascript).Can anyone throw some light on this or direct me to a tutorial?
Where exactly is this code supposed run? Surely not on the client-side. Client-side native code is nowhere near mass adoption.
GWT can either interface with JSNI in order to write native JS code inside your GWT Java code, or to interface with Java back-ends, whilst the framework handles the RPC. Even without GWT you have no way to run native code from within the browser (at least in the near future).
Bottom line - if you can't do it in plain vanilla Javascript on the client side, you can't do it in GWT.
What you can do is use this native code in the back-end, and call it via classic JNI from your Java back-end classes (and then what difference does it make if it's part of a GWT project or not?), but it sounds like this is not the case.
First of all, have a clear separation of Client (HTML / Javascript running in the browser) and server components (java service servlets).
If I understood your problem statement right, You need the UI to collect parameters for your transcoders and your transcoders need to run on a Windows box.
You can look up any simple GWT application to figure out how to serve a GWT application in any container (perhaps jetty for the time being) and process basic HTML form inputs. Once you have all the parameters on the server, you need to figure out how to delegate these parameters posted from the browser (your GWT application) from the service servlet (running within a web server) to your DirectShow application. This point onwards its a java application talking to a native process problem.
You can use various ways to communicate parameters to your native directshow application. Simplest solution is to initiate the application with the exec method passing command parameters inline. Otherwise you can communicate to a running native application via TCP sockets or integrate the native app using JNI. It all depends on your architectural design, which approach you wish to take.
I've got a GWT application, which periodically needs to update the screen with new tick items as they come in. We also have messages published by a CometD/Bayeux server (for a different AJAX application) and I'd like to consume them in my GWT.
Of course, I can drop into JavaScript, hook up Dojo, and receive callbacks in the JavaScript layer - and from there, route a call into GWT Java code via a JSNI - but there doesn't appear to be any support in GWT directly for using long push or async calls other than the non-RESTful RPC.
How have you integrated GWT and Bayeux?
Since this question was originally posted there have been a few advances:
http://code.google.com/p/google-web-toolkit-incubator/wiki/ServerPushFAQ
http://code.google.com/p/gwteventservice/
http://code.google.com/p/gwt-comet/
JSNI is not that bad option as it might sound first. There is a DZone refcardz 'GWT: Style, Configuration and JSNI Reference' which I have found helpful.