With a new official add-on in the Vaadin directory, the Vaadin web application framework is taken to a new level: the Vaadin Spreadsheet add-on lets you load Microsoft Excel files in a Vaadin Spreadsheet component to be displayed and edited in the browser. This often requested and never quite achieved requirement can now be very easily fulfilled with a Vaadin application. With this add-on it is now possible to write web applications that let your users work collaboratively on the same set of spreadsheets without having to resort to sending around Excel files by email or working with network shares.
Screenshot from the Vaadin Spreadsheet online demo
The add-on internally makes heavy use of the Apache POI library, so it is based on an already well-known and established Java API for Microsoft Documents.
You should check out the online demo for Vaadin Spreadsheets on the Vaadin homepage.
The add-on is still released as a beta version but with a feature complete and stable API. Vaadin Spreadsheet is a non-free add-on and can be used commercially with a Vaadin Pro Tools subscription.
With version 7.4 Vaadin have released the next minor update of their web framework. This release introduces two very powerful new features: a brand new table component named Grid and declarative layouts.
After several months of development, Balsamiq recently released a public beta for the next major version of its mockup tool: Balsamiq Mockups 3-Public beta.
The propably most important change in this version is the new way of project management which makes it easier to keep track of the contents and to share them with others.
Balsamiq Mockups 3 introduces a new file format for its projects (BMPR). It contains all mockups, images and other required sources, i.e. it no longer requires a special folder structure. Balsamiq Mockups projects from previous versions can be easily imported to the new format.
In addition, it provides an improved user experience by the use of Autosave functionality, a fixed arranged Property Editor, simplified handling of Symbols and some more.
For the moment, these great new features are available in Balsamiq Mockups 3 for Desktop only. But it is planned to bring them on mybalsamiq and the various plugins, as well.
Die Aufgabe klingt erstmals einfach, und die Antwort auf die Frage “geht das auch noch, wenn wir auf Gradle umsteigen?” beantwortet man ganz gerne mit “ja, das müsste out-of-the-box problemlos möglich sein.”
Es geht hierbei um eine gar nicht so nicht-alltägliche Aufgabe. Eine Webapplikation in Form eines WAR Archives soll für das Deployment auf dem Applikationsserver in ein EAR gepackt werden. Für bestehende Buildprozesse, zum Beispiel Ant-basierend oder auch Eclipse, stellt dies keine größere Hürde dar, handelt es sich doch um ein in der Spezifikation vorgesehenes Szenarium.
Als Groovy und Grails Befürworter musste man gerade die überraschende Nachricht von Pivotal verkraften, dass sich das Unternehmen nach dem Release der nächsten Versionen Ende März 2015 aus der direkten Finanzierung beider Open Source-Projekte zurückziehen wird.
com.vaadin.ui.ComboBox the Vaadin Toolkit provides a drop-down selection component that allows you to select an item from a set of values by offering a list of suggestions based on your current input. This works out of the box without having to implement the suggestion logic yourself. You only need to provide a list of selection items that you’ll put into the ComboBox as its data model and then specify the desired filtering mode.
This has one caveat, though. If the list of selectable items contained in the ComboBox is very large, you cannot use this component in a memory-friendly way. That’s because all of the available items in the ComboBox need to be kept in the user session for the suggestion logic to work. You cannot dynamically load suggestions from some external storage and feed them to the drop-down list on demand.
In this article, I’m going to describe a way how you can tweak Vaadin’s ComboBox in such a way that loading suggestions from an external service is possible after all.
A few days ago, Spring Session 1.0 has been released. According to the project page, it provides the following functionality:
- API and implementations (i.e. Redis) for managing a user’s session
- HttpSession – allows replacing the HttpSession in an application container (i.e. Tomcat) neutral way. Additional features include:
- Clustered Sessions – Spring Session makes it trivial to support clustered sessions without being tied to an application container specific solution.
- Multiple Browser Sessions – Spring Session supports managing multiple users’ sessions in a single browser instance (i.e. multiple authenticated accounts similar to Google).
- RESTful APIs – Spring Session allows providing session ids in headers to work with RESTful APIs
- WebSocket – provides the ability to keep the HttpSession alive when receiving WebSocket messages