I find no documentation on how to update objects vaadin asynchronously. Can anyone help me? What I need is to render a table and then update the values of a column with a call rather slow, and so I want to make it asynchronous ..
This has been discussed a lot on this thread on the Vaadin forum. You might want to read it, it contains a lot of useful information.
Just do the updates in another thread. UI modifications from background threads must be synchronized to application object. Add icepush, refresher or proggresbar to get changes from server to client.
As far as I know Vaadin provides two add-ons for solving this problem: ServerPush and DontPush. Both add-ons can be imported via maven and both support WebSockets as well as fallback solutions for browsers without WebSocket support. Although ServerPush provides seemingly more features than DontPush, it is lower rated than DontPush, probably because it is more complicated.
For pushing updates to the client DontPush provides a very simple solution that does not require any changes to the web application. Only the servlet-class in web.xml needs to be replaced by org.vaadin.dontpush.server.impl.jetty.DontPushServlet and the widget set has to be updated afterwards via mvn vaadin:update-widgetset. That's all. Any changes on the server will be automatically pushed to the client. I successfully tested this add-on with Chrome 14. Unfortunately, I could not get it working with Firefox 7.
According to the web page of ServerPush the ServerPush add-on should provide this functionality, too. However, I could not figure out how to setup ServerPush to be working with jetty. Moreover, it seems to be more complicated in use. It requires several changes to the web.xml as well as additional configuration files for the atmosphere server.
In contrast to DontPush ServerPush provides also an explicit pushing mechanism which allows to update the GUI manually by calling the push() method of a certain pusher component which needs to be added to the main window beforehand. However, I also failed to get this working.
Related
Looking at some of the sample code for hybrid mobile apps that speak to Node.js on BM (http://mbaas-gettingstarted.ng.bluemix.net/hybrid), you will see various examples that demonstrate how to use a logger on the client side:
var config = {
applicationId:'<applicationId>',
applicationRoute:'<applicationRoute>',
applicationSecret:'<applicationSecret>'
};
IBMBluemix.initialize(config).done(function(status){
// Initialize the Services
}).catch(function(err){
IBMBluemix.getLogger().error("Error intializing SDK");
});
I've confirmed this works fine in a Cordova app. My question is - why does this exist? As far as I can see, it does nothing more than wrap calls to console.log. It does not ever send logs to the Bluemix server app as far as I can tell.
There is documentation here, https://www.ng.bluemix.net/docs/starters/mobile/mobilecloud/nodejsmobile.html#log, that talks about the feature both server-side and client-side, but unless I'm missing it, there's no persistence for the client-side version.
If so - then what exactly is the point of this abstraction then? I have to imagine it was built for some reason, but I'm not seeing it.
this wrapper is used to "wrap" and to make "standard" the console log api, especially because this javascript API isn't available for all the browsers (especially old ones). By wrapping it the library could check the browser and its availability, in order to avoid an execution error
Another reasons is to wrap some configuration utilities, like providing different libraries to use (eg log4js) or other configuration, and so on.
Last but not least, probably it provide a singleton interface for performance optimization
I'm in the process of exposing some of the data generated in one OSGi bundle with a REST interface so it can be consumed with typical http requests afterwards by anyone. To do this I'm using a combination of apache-cxf, JAX-RS and Jetty (for testing purposes mostly).
My whole application is distributed in two ways:
Core: Runs a set of minimal bundles as an OSGi framework.
Full: Core + plus a set of plugins to be used within Eclipse, in a graphical way, to put it that way.
While in the Core launch configuration I can make this work without any problems, have a look at the MANIFEST:
Require-Bundle: cxf-dosgi-ri-singlebundle-distribution;bundle-version="1.3.1",org.eclipse.core.runtime, org.eclipse.osgi.services;bundle-version="3.3.0", org.mortbay.jetty.server;bundle-version="6.1.23", org.mortbay.jetty.util;bundle-version="6.1.23"
When I try to launch the Full distribution, jetty server does not seem to start and thus, the RESTful service is not working properly. Full distribution comes with a lot more plugins, mostly related with wizards, perspectives and so on. Root of this problem is somehow related with the cxf-dosgi-ri-singlebundle-distribution bundle, and can be tackled by "forcing" auto-start of this bundle to true, instead of default (check image below):
While this is OK, my question is ...why is this happening? And second and most important, I distribute the Full distribution via an update site, so users can download it, open perspective and start using it, that said, will this affect the final distribution? Is there a way I can control this auto-start=true for the apache-cxf bundle in the update site?
Hope I can make myself clear...
Thanks!
I don't like answering my own questions, but since I'm getting no feedback and maybe someone else has the same problem...here it goes
I decided to change the whole design of my restful bundle, by not using apache-cxf, since it is really not needed. All I need to do what I want is the embedded Jetty server and javax for dealing with HttpRequests and HttpResponses. Thus, I get rid of dependecies with third party libraries, leveraging the launching problems at the same time.
Got the ideas from these official sites in Eclipe:
Embedding an HTTP server in Equinox
Writing a bundle-based server application
Besides, a more hands-on tutorials can be also found here:
OSGi as a Web Server application
Extending Eclipse: displaying HTML content from a bundled archive
Special thanks to both authors for the enlightenment :).
We're planning on creating a feedreader as a windows desktop- and iPad application. As we want to be able to show Websites AND to run (our own) JavaScript in this application, we thought about delivering the application as HTML/CSS/JavaScript, just wrapped by some .NET control or a Cocoa Touch webbrowser component. So the task at hand is to find out which framework to use to create the HTML/CSS/JS files to embed in the application.
For the development of the HTML/CSS/JavaScript we would be happy to use Vaadin, GWT, or some other framework, as we're a lot better with Java than with JS. We favor Vaadin after a short brainstorming, as the UI components are very nice, but I fear that most of the heavy lifting will be on the server and not in the client (and that wouldn't be too nice). We would also like GWT, but the Java-to-JS compiling takes a lot of time and an extra step, and slowed down development time in the past when using it.
The question is: which development framework would you choose (given you wanted to implement this project and you mostly did Java so far) and why? If there are better framework options (List of Rich Client Frameworks), please let me know.
Edit: The application will need to talk to our server from time to time (sync what has been read for example), but mainly should get the xml feeds itself. Therefore I hope that most of the generated code can be embedded in the application and there doesn't need to be heavy activity with our server.
Edit2: We (realistically even if you doubt) expect at least 10000 users.
Based on my experience with Vaadin, I'd go for that, but your requirements are somewhat favoring pure-GWT instead.
Vaadin needs the server and server connection. If building mostly offline desktop application, this can be solved with an embedded Jetty for example. (synchronize with an online service only when needed), but for iPad you would need to connect online right away to start the Vaadin application.
GWT runs completely at the client-side and you can build a JavaScript browser application that only connects when needed.
Because Vaadin is much quicker to develop, you could build a small Vaadin version first and see if that is actually problem on the iPad.
On the other hand, if you can assume going online right away, you can skip the local server installation altogether. Just run the application online and implement the desktop version using operating systems default browser control (i.e. the .NET control you suggested). Then Vaadin is easier.
Vaadin is just framework base on GWT but have two very important features:
don't need to run GWT compiler. It is pure java. Of course if not add addons because then gwt compiler must run.
you don't need to write communication code. So you don't need to solve DTO problems, non-serializable object mappings and dont need to write servlets.
I use Vaadin in my work for one year and we haven't performance problems yet (desktop like application with ~500 users). IMO very good solution is to use Vaadin just for UI, logic move to independent beans and connect this two elements using Spring or Guice.
In this case you should use MVP pattern and Domain Driven Development.
Bussines beans is domain objects and logic that use view interfaces to send responses.
Custom Vaadin components (could extends standard components) implements view interfaces.
That way is good when you decide to change UI engine if Vaadin is not for you. Just rewrite guice/spring mappings and write new implementations of view interfaces.
My 3 cents:
If you decide to use vaadin, You will benefit from already GOOD LOOKING components. Since you dont want to write (alot of) CSS , vaadin is already good looking out of the box. How ever, Vaadin is a SERVERSIDE framework. User interface interactions will hit the back end even if they dont involve getting any data (e.g moving from one tab to the other) .
If you decide to use GWT, you will have to atleast style the application (this is not hard) . There is also the problem of long compilation time (but you can test and debug on hosted mode which allows you to run the application without compiling , then you compile only when deploying). The main advantage of gwt is that you control what gets sent to the wire, For UI interactions that dont require getting data from the backend, it will work purely on the client side. You the developer will determine when to send a request to the back end. (Doing RPC requests in GWT is very easy)
Hope this will help you make the decision.
I'm in the middle of converting an existing app built on top of zend framework to work as a plugin within wordpress as opposed to the standalone application it currently is.
I've never really used zend so I've had to learn about it in order to know where to begin. I must say that at first I didn't think much of zend, but it's funny because the more I understand how it works the more I keep questioning why I'd want to remove dependency when it's a clearly well thought out framework. Then I'm reminded that it's because of wordpress.
Now I already know there are WP plugins to make zend play nice with WP. In fact I'm aleady using a zend framework plugin just to get the app functional within the WP admin area which is allowing me to review code, modify code, refresh the browser, review changes, debug code, again and again.
Anyway, I really don't have a specific question but instead I'm looking for advice from any zend masters out there to offer advice on how to best go about a task like this one.... so any comments, advice, examples or suggestions would be super.
One area I'm a little stuck on is converting parts of zend->db calls to work as wpdb calls instead... specifically the zend->db->select.... not sure what to do with that one.
Also on how to handle all the URL routing with automatic calls to "whatverAction" within thier respective controllers files.
Any help would be great! Thanks
You're probably facing an uphill battle trying to get some of the more major components of ZF to work in harmony with Wordpress. It sounds like you've got a full MVC app that you're trying to integrate into a second app that has very different architecture.
You probably want to think about which components handle which responsibilities. Wordpress has it's own routing and controller system that revolves around posts, pages and 'The Loop'. This is entirely different from Zend's Action Controllers and routing system.
It's possible you could write a WP hook to evaluate every incoming request and decide if it should be handled by WP or a ZF controller. However, it is doubtful you would be able to replace WP's routing system outright with ZF's or vice versa.
Same idea, where Zend_Db is concerned. There's nothing stopping you from using Zend_Db to access Wordpress's database, but trying to somehow convert or adapt Zend_db calls into wpdb calls sounds painful. If you have a large model layer, you probably want to hang on to it, and find a way to translate data from those models into the posts/pages conventions that Wordpress uses.
Personally, I would use ZF to build a robust business layer that can be queried through an object model via a Wordpress plugin, and then rely on Wordpress to do the routing and handle the views.
Zend_DB_Select is simple SQL query (but created using objects) that can be used like any other query. Just turn it into string. Ex.:
mysql_query((string)$zendDbSelectObject);
Hey guys. We're using OSGi services in an Eclipse RCP application. To track them, we're using the org.osgi.util.tracker.ServiceTracker class. A sample code from the application looks like
mailServiceTracker = new ServiceTracker(context, MailService.class.getName(), null);
mailServiceTracker.open();
MailService service = (MailService) mailServiceTracker.getService();
Now my problem is that the getService() method frequently returns null when I created a new service. The code works very well for services that are existing for a long time in the application, but each time I create a new service, I have to do many things until the service is finally found and tracked. I regularly try for example
'Clean...' in Eclipse
'Refresh' all projects in Eclipse
Rebuild the project on the command line
Sometimes those things help, and sometimes they don't. Does anyone have experiences with those trackers and can tell me how to avoid this behavior and how to get the services tracked immediately upon creation?
Thanks
The problem is that the services you want may not have been created yet (especially in an bundle activator, as some bundles may not yet have started). If you still want to use the service tracker, you will need to provide a ServiceTrackerCustomizer, and keep track (sorry, no pun intended) of the services as they come and go.
Or, you could just switch over to Declarative Services that handle this for you.
There is nothing wrong with using ServiceTrackers other than the fact that it's a fairly low-level way of tracking services. Whilst I agree that declarative services are a nice mechanism, simply dismissing ServiceTrackers because of "all sorts of issues" sounds like bad advice.
Back to the question.
As soon as a service tracker is created and opened, it gives you access to all services that match the filter condition you specified upon creation. There is no delay there. The only thing I can think about is that somehow your bundles are not correctly resolved, so services that are registered from a bundle A are simply not visible to a bundle B using a ServiceTracker. To check this, first locate the bundle that exports the package containing the service interface, and then make sure both A and B are actually wired to it.
Explaining the update/refresh mechanism in OSGi a bit more:
Whenever you update something in OSGi, it's a two step process.
Let's assume you update a bundle that contains a new version of an exported package. Let's also assume there is some consumer that imports it. As long as you only update the bundle but not explicitly refresh the wiring (of which import links to which export) the consumer will still be wired to the old version of the package. As soon as you do a package refresh (something you can do in OSGi via the PackageAdmin service) your consumer will be resolved again and will be wired to the new version.
The reason this is decoupled is that you might want to do updates of several bundles and not "refresh" after each one but instead defer such a refresh until all of them are updated.
It's quite possible that this is the effect you're seeing. Initially you only do an update, and only after the refresh will the tracker actually see the new version of the service.
Not being flippant at all, don't use service trackers. They appear to make your life simple, but there are all sort of issues with them. I'd recommend that you look into using Declarative Services instead. The support for DS in Eclipse has been very good from 3.5 onward.
You might want to check out this book and the associated presentations for more information on why using Service Trackers is a bad idea.
http://equinoxosgi.org/