Video for lesson 19 of OpenXava course

In this new lesson we're going to continue with validations. We'll see three different ways to do validation with OpenXava, all of them simpler than @EntityValidator you learned in the previous lesson. These three ways are: @PrePersist/@PreUpdate JPA callback methods, putting the validation in the setter and a method with a Bean Validation annotation. Watch the video.

Video for lesson 18 of OpenXava course

In this new lesson of our course we're going to start the part of the course devoted to validations, that is how to verify that the data the user enters is correct. We'll start with the @EntityValidator annotation to add validations at entity level.  Watch the video.

OpenXava in Chinese

Historically OpenXava documentation has been available in English, Spanish, Russian, French and Chinese. However, the latter three were contributed by the community and no longer maintained. Therefore, newcomers using Russian, French or Chinese found documentation obsolete and that did not match with the current OpenXava version, producing a less than optimal learning experience. To fix this, we have decided to completely remove the Russian and French versionS, so Russian and French developers can use the always up-to-date English docs. 

About Chinese, we're translating from scratch directly from the Spanish (up-to-date) documentation to Chinese by a member of our team that is native in both languages. Moreover, we're going to maintain Chinese documentation up-to-date, at the same level as English and Spanish counterparts.

Also, we have translated the complete openxava.org site to Chinese and version 7.0 will have all labels and messages included in OpenXava in Chinese.

We already have many lessons from the OpenXava course translated to Chinese, if you know Chinese we invite you to have a look.  

Video for lesson 17 of OpenXava course

In this new lesson of our course, you'll learn to use the Hibernate @Formula annotation in your OpenXava entities, so you can map a SQL statement to a property. This allows you to have properties with a calculation where you can search and filter in list mode. Watch the video.

Video for lesson 16 of OpenXava course

Calculated properties, those with just a getter, allows you to define any imaginable calculation using Java, but given that they have not a column in the database, your user cannot search or sort for that property. A way to solve this problem is to have a persistent property too, and synchronizing both, persistent and calculated, using a JPA callback method. It's not so difficult, watch the video.