Welcome!

IBM Cloud Authors: Elizabeth White, Yeshim Deniz, Pat Romanski, Liz McMillan, Stefan Bernbo

Related Topics: Java IoT, Open Source Cloud, Machine Learning , Apache

Java IoT: Article

OpenXava 4.5: Rapid Java Web Development

OpenXava allows you develop applications just by writing simple domain classes with Java or Groovy

OpenXava is a framework for Rapid Java Web Development, well-suited for business and database oriented applications.

OpenXava allows you develop applications just by writing simple domain classes with Java or Groovy. The user interface is generated automatically in runtime, without code generation.

OpenXava 4.5 has some new interesting features such as:

  • Support for all strategies of JPA inheritance mapping.
  • Data for list and collections is obtained via JPA, before JDBC was used.
  • Automated Business Logic (ABL) library added.
  • All new layout architecture (the code that paints the UI). It still in BETA but can be activated with layout.painter in xava.properties.

And many other useful new features and bug fixes.

Support for all strategies of JPA inheritance mapping

This feature has been demanded for long time by the community. Until now only single table per class hierarchy mapping strategy was supported, that is the case where all classes hierarchy is stored in the same table. Since OpenXava 4.5 you can also use joined and table per class mapping strategies.
That is, you can write some classes in this way:

@Entity
@Inheritance(strategy=InheritanceType.JOINED)
class Computer extends Identifiable {
String name
}

@Entity
class Tablet extends Computer {
int screenSize
}

In this case, you have a table for Computer with ID and NAME columns  and a table for Tablet with ID and SCREENSIZE columns. JPA will do a JOIN of the two table when needed.
Also you can write:

@Entity
@Inheritance(strategy=InheritanceType.TABLE_PER_CLASS)
class Shop extends Identifiable {
String name
}

@Entity
class InternetShop extends Shop {
String url
}

In this case, you have a table for Shop with ID and NAME column and another for InternetShop with ID, NAME and URL columns.
From now on OpenXava will generate a correct user interface for the above classes.

Data for list and collections is obtained via JPA

Until now OpenXava has used JDBC to get the data for list and collections. It was in this way for historical reasons, specially because the very first version of OpenXava used EJB 1.0 CMP entities for persistence and EJB CMP is too slow and rigid to implement the OpenXava list behavior, so we used JDBC. But now, JPA is rapid and flexible enough to be used for obtaining the list data, so we have written a new JPATabProvider to read the data of the list, and it is the one used by default. This allows us to support all the inheritance JPA types, but also opens many interesting posibilities for the future, such as using DataNucleus instead of Hibernate as JPA engine to access to non-relational databases.

Automated Business Logic (ABL) library added

The folk from the California startup Automated Business Logic have been working hard to integrate their library, ABL, in OpenXava. ABL allows you to define business logic declaratively using annotations. The wiki explains how to use ABL from OpenXava.

All new layout architecture (the code that paints the UI)

The people from SicFlex, a Dominican company that has developed a complete ERP with OpenXava, have developed a new render engine for OpenXava. This is the more important and complicated part of OpenXava. This new render engine will generate even more complex and beautiful user interfaces for OpenXava applications. It is still in beta and it's disabled by default, but you can activate it with the next entries in xava.properties:

# Layout parser calculate and prepare properties to be renderer.
# This is optional, by default OX uses org.openxava.render.DefaultLayoutParser
layout.parser=org.openxava.web.layout.DefaultLayoutParser

# Layout painter, render all properties in cell forms
# If a valid painter is defined here, view rendering is performed by it.
layout.painter=org.openxava.web.layout.DefaultLayoutPainter

And more

See changelog for the complete list of new features and fixes.

Download OpenXava 4.5 and try it

More Stories By Javier Paniza

Javier Paniza is the project lead for OpenXava project. He works as software developer at Gestión 400, a software company for public administration in Spain. He has been developing with Java Enterprise since 1998. Also he has been J2EE mentor for development teams in banking projects.

IoT & Smart Cities Stories
To Really Work for Enterprises, MultiCloud Adoption Requires Far Better and Inclusive Cloud Monitoring and Cost Management … But How? Overwhelmingly, even as enterprises have adopted cloud computing and are expanding to multi-cloud computing, IT leaders remain concerned about how to monitor, manage and control costs across hybrid and multi-cloud deployments. It’s clear that traditional IT monitoring and management approaches, designed after all for on-premises data centers, are falling short in ...
DXWordEXPO New York 2018, colocated with CloudEXPO New York 2018 will be held November 11-13, 2018, in New York City and will bring together Cloud Computing, FinTech and Blockchain, Digital Transformation, Big Data, Internet of Things, DevOps, AI, Machine Learning and WebRTC to one location.
We are seeing a major migration of enterprises applications to the cloud. As cloud and business use of real time applications accelerate, legacy networks are no longer able to architecturally support cloud adoption and deliver the performance and security required by highly distributed enterprises. These outdated solutions have become more costly and complicated to implement, install, manage, and maintain.SD-WAN offers unlimited capabilities for accessing the benefits of the cloud and Internet. ...
Business professionals no longer wonder if they'll migrate to the cloud; it's now a matter of when. The cloud environment has proved to be a major force in transitioning to an agile business model that enables quick decisions and fast implementation that solidify customer relationships. And when the cloud is combined with the power of cognitive computing, it drives innovation and transformation that achieves astounding competitive advantage.
DXWorldEXPO LLC announced today that "IoT Now" was named media sponsor of CloudEXPO | DXWorldEXPO 2018 New York, which will take place on November 11-13, 2018 in New York City, NY. IoT Now explores the evolving opportunities and challenges facing CSPs, and it passes on some lessons learned from those who have taken the first steps in next-gen IoT services.
SYS-CON Events announced today that Silicon India has been named “Media Sponsor” of SYS-CON's 21st International Cloud Expo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Published in Silicon Valley, Silicon India magazine is the premiere platform for CIOs to discuss their innovative enterprise solutions and allows IT vendors to learn about new solutions that can help grow their business.
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...
SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5–7, 2018, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buye...
Founded in 2000, Chetu Inc. is a global provider of customized software development solutions and IT staff augmentation services for software technology providers. By providing clients with unparalleled niche technology expertise and industry experience, Chetu has become the premiere long-term, back-end software development partner for start-ups, SMBs, and Fortune 500 companies. Chetu is headquartered in Plantation, Florida, with thirteen offices throughout the U.S. and abroad.
The standardization of container runtimes and images has sparked the creation of an almost overwhelming number of new open source projects that build on and otherwise work with these specifications. Of course, there's Kubernetes, which orchestrates and manages collections of containers. It was one of the first and best-known examples of projects that make containers truly useful for production use. However, more recently, the container ecosystem has truly exploded. A service mesh like Istio addr...