Integrating Vaadin Applications with other technologies

Preface

The intention of this article is not to show how to integrate Vaadin with some other technology, but to tell user-stories from both easy and hard customer cases where Vaadin has been combined with something else. It should also give you a pointer to what is possible and what is not.

Please see the wiki for more extensive technical articles on various subjects. If you are interested in learning more from our developers, please contact us through our forums. The forum messages are usually answered very rapidly (read: within a few hours during business hours).

User stories

Cloud computing and Vaadin

Amazon’s EC2 really takes creating and serving Vaadin applications to a new level. You can literally have a new server running with server, portal and application in couple of minutes and it all just works. Of course this not only applies to Vaadin applications, but together they are a perfect fit! -Joonas Lehtinen

CMS (ala Liferay) and Vaadin

We wanted to be able to show some pop-up application windows that were part of our Vaadin application and that the customer themselves could write the links in their CMS without hassle. What we did was that we created an invisible Vaadin application that listened to the URL and whenever it changed due to a click on a link, it launched a new pop-up window. The solution was also highly scalable as 30.000+ users are using it daily already. -Johannes Tuikkala

Custom UI components to browser with Java

Creating your own widget for Vaadin is very easy thanks to the new eclipse plugin. All you need to do is select "Create new Widget" in eclipse and all the server and client side code is automatically generated for you. Then you’ll just create the widget using Java and GWT. Using the eclipse plugin it is also much faster to set up a new Vaadin project. -Matti Tahvonen

Drools and Vaadin

We required a flexible way to validate internal dependencies in highly dynamic data structures. We solved our need by integrating the Drools rule engine in our application, and with it we got a powerful content-triggered autocompletion mechanism as a freebie. We wrapped the rule engine behind a general API in a EJB, so the rule mechanism can be used by all components of the application architecture. -Henri Muurimaa

Extending existing components

We had a real business need for few important widgets that just were not available in Vaadin. So we extended the current table and came up with hierarchical table aka treetable. Another simple but important widget was multilingual text field. It acts just like normal textfield but when opened, you get the java field opened with multiple locale instances, it has nice UI too including user friendly flags. Great for handling i18n based data in your UI. We got multiple customer cases that enjoy these new widgets. -Jani Laakso

Flex and Vaadin

Flex is really excellent for animations and flashy things and in this way is an ideal candidate for creating something really good looking together with Vaadin. I created a proof-of-concept flex-Vaadin application that communicates through GWT by wrapping the flex component and implementing Vaadin’s paintable interface. If you know flex from before or have teams that know flex and others that know Java then this is an ideal combination. -Kim Leppänen

Google Analytics Integration

For the Sampler application, we wanted to be able to see which 'samples' are interesting to the users. GWT makes it easy to integrate with JavaScript APIs, and thus making a Google Analytics component was a breeze, even without using existing GWT/Java efforts. -Marc Englund

Graphics with JFreeChart

It turned out surprisingly easy to add various charts to reports generated by a web application. All we needed to do is create the JFreeChart chart object and an Vaadin component automatically displays it as SVG or PNG graphics depending on the browser used. -Henri Sara

GWT Components to Vaadin

I wanted to create a Vaadin component out of Google’s !GoogleMaps GWT Widget. In order to do this you needed to create a widgetset that includes the component and implement two methods that are required for communication between the client and the server. Quite straight forward. See the code in the incubator (link below). -Henri Muurimaa

Javascript libraries and Vaadin

For the Sampler application, I made a code formatting and colorizing component, which makes use of the "google-code-prettify" JavaScript library. I’ve found existing JavaScript libraries are easy to use with GWT on the client-side. -Marc Englund

JQuery, Dojo and Prototype with Vaadin

Combining Vaadin applications and client-side javascript libraries is a very interesting use-case and a very easy one to implement as well. The easiest way to accomplish this is to use a !CustomLayout with the Javascript you want. See a short demo I made below. -Joonas Lehtinen

LaTeX and Vaadin

This was no doubt a very exotic combination. Our customer wanted to be able to create books that could be sent to printing based on huge amounts of data. We wrote an advanced parser (using DOM and SAX parsers) that created a file that LaTeX could interpret. LaTeX then created a PDF that was saved in a database and a link showed up in the webshop. Whenever you clicked on the link, you got finalized PDF that could be sent to printing and as a result you got a full several hundred pages long book. -Jani Laakso

Leveraging existing Java libraries in the browser

Recently, while making a gesture recognition component, I was able to use the Levensthein Distance algorithm implementation from the Jakarta Commons project, without any modification.The use of GWT makes it possible to leverage existing Java code on the client side - within own projects, or by making use of the vast amount of libraries available for Java. -Marc Englund

MOSS and Vaadin through IFrame

The goal was to get a Vaadin application running inside the Microsoft Office Sharepoint Server (MOSS) as a portlet. What we did was that we wrote our Vaadin application and deployed it on a JBoss portal. We then took the application’s URL and used MOSS' !PageViewer Webpart to have it include the application inside an IFrame. It was actually much easier that I thought. -Johannes Tuikkala

MOSS and Vaadin with Sharepoint SSO

The goal was to integrate a Vaadin application to MOSS as portal. Priority was to use SSO by Sharepoint. This was accomplished doing custom integration Webpart with C# that transfered authentication information to Vaadin before it was opened with-in IFRAME. -Mauno Haukila

N-tier JEE architecture with Vaadin

We have found in several larger customer cases that the best possible architecture is to separate the UI-layer from the rest. Never mix your business logic inside UI logic, there’s no need to. This way the UI can be replaced in the future and also when updating old systems to use Vaadin (e.g. SWING applications that are written this way) it has been a breeze when the only thing that needs to be rewritten is the UI. Another very important factor is security, trust your data layer, do not trust your clients, using enterprise beans with JNDI helps you. Scalability and high-availability are also easier to cope with. Scale up with multiple cheap Tomcat machines acting as Vaadin clients, few powerful data servers as JBoss cluster and a good SQL server. -Jani Laakso

Offline / standalone applications

I’ve made offline / standalone Vaadin applications by integrating an embedded servlet container (Jetty and Winstone so far) with Xulrunner. This is actually a quite straightforward process, requiring only a few lines of code for the basic functionality. It’s really the distribution (making installers and such), and the actual application that’s the hard part. -Marc Englund

Opensource stack for customer projects

One of our customers asked us to help them with selecting an open source stack for their open source product portfolio. What we came up with was based on our own experiences and is by no means the only possibility. What it shows though, is how Vaadin is only part of the UI layer and everything beneath it can be almost anything. -Ville Ingman

Pentaho BI Suite and Vaadin

Yet another way to create PDF files, but this time really tightly integrated with Vaadin. We had some data in a Vaadin table that we wanted to print as a PDF file. As each component in Vaadin has a container, the most natural way was to take the data from the container, send it through a wrapper and give it to Pentaho. Pentaho then created the PDF files without any problems. So whenever somebody wanted to print the data they were viewing in a scrollable table, they just clicked a button and everything was taken care of in the background. -Jani Laakso

Portlets with Vaadin

The only thing you have to do in practice when you want to write a portlet is add the portlet.xml file, where you define Vaadin’s !ApplicationPortlet as the entry point. After this your application will work inside the portal. The only situation where you need to edit the Java code as well is when you want to use some portal/portlet specific features. This gives you the possibility to first develop a standard Vaadin application and then later, by just adding the portlet.xml file you have it working inside a portal. -Jonas Granvik

PDFs (FOP+iText) and Vaadin

When creating my printing service I used Apache FOP and iText to create PDF files from multiple XML/XSLT/PDF files just as you would normally in any Java application. The thing I found the most powerful however was the combination with these two products together with Vaadin’s Embedded component. I just created the object, setSource() to my byte array and the PDF showed up in my browser together with all the buttons and widgets I also wanted on the screen. The user experience was significantly enhanced compared to having to download the PDF and click on some button in an external window. -Fredrik Rönnlund

SAAS with Vaadin

When writing our application as a service we had to do some serious planning beforehand as the application was going to be used by so many people. What we did was that we had one database for all users and then inserted the instance ID in all HQL/SQL clauses to be sure we were always accessing the correct instance. The instance was select at login. This didn’t require any specific things from the UI part, which was created using Vaadin. -Jani Laakso

Single Sign On (SSO) to Liferay

Writing a Single Sign On portlet was really easy. A Vaadin application by default only requires to be packaged as a portlet in order to work inside a portal and then by using the provided API to the portal you can easily retrieve all login information. This way the user doesn’t need to login several times and context handling is also done easily. -Jani Laakso

Unit testing Vaadin applications

Unit testing Vaadin applications is no different from unit testing any java application. What we have done however is separate the GUI from the !BusinessLogic (even so far that they are running on physically different servers). This way our most extensive testing is done on the business logic, but also on our Controller in the GUI. Having Unit tests in general has helped us build more solid applications, on all layers. -Kim Leppänen

Web 2.0 APIs and Vaadin

Many "Web 2.0" APIs already have GWT bindings, making it trivial to use these. Even without existing bindings, it’s easy to use JavaScript APIs from GWT, or REST/JSON/XML/etc APIs from the server-side.Google Maps, Google Analytics, Flickr, Youtube - these are some "Web 2.0" APIs that have been used. -Marc Englund

Webservices and Vaadin

Integrating a webservice with Vaadin was really a no brainer. What we had was a UI that had to check something through a service-provider’s Webservice. So when ever the UI launched the check, we called the webservice (with Pojos created by the WSDL file that we got from the service provider) and got some other Pojos as a reply. The reply then dictated what the UI would look like. -Johannes Tuikkala