Welcome!

Java IoT Authors: Liz McMillan, Pat Romanski, TJ Randall, Zakia Bouachraoui, Elizabeth White

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
At CloudEXPO Silicon Valley, June 24-26, 2019, Digital Transformation (DX) is a major focus with expanded DevOpsSUMMIT and FinTechEXPO programs within the DXWorldEXPO agenda. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive over the long term. A total of 88% of Fortune 500 companies from a generation ago are now out of business. Only 12% still survive. Similar percentages are found throug...
AI and machine learning disruption for Enterprises started happening in the areas such as IT operations management (ITOPs) and Cloud management and SaaS apps. In 2019 CIOs will see disruptive solutions for Cloud & Devops, AI/ML driven IT Ops and Cloud Ops. Customers want AI-driven multi-cloud operations for monitoring, detection, prevention of disruptions. Disruptions cause revenue loss, unhappy users, impacts brand reputation etc.
At CloudEXPO Silicon Valley, June 24-26, 2019, Digital Transformation (DX) is a major focus with expanded DevOpsSUMMIT and FinTechEXPO programs within the DXWorldEXPO agenda. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive over the long term. A total of 88% of Fortune 500 companies from a generation ago are now out of business. Only 12% still survive. Similar percentages are found throug...
Atmosera delivers modern cloud services that maximize the advantages of cloud-based infrastructures. Offering private, hybrid, and public cloud solutions, Atmosera works closely with customers to engineer, deploy, and operate cloud architectures with advanced services that deliver strategic business outcomes. Atmosera's expertise simplifies the process of cloud transformation and our 20+ years of experience managing complex IT environments provides our customers with the confidence and trust tha...
The Japan External Trade Organization (JETRO) is a non-profit organization that provides business support services to companies expanding to Japan. With the support of JETRO's dedicated staff, clients can incorporate their business; receive visa, immigration, and HR support; find dedicated office space; identify local government subsidies; get tailored market studies; and more.
At CloudEXPO Silicon Valley, June 24-26, 2019, Digital Transformation (DX) is a major focus with expanded DevOpsSUMMIT and FinTechEXPO programs within the DXWorldEXPO agenda. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive over the long term. A total of 88% of Fortune 500 companies from a generation ago are now out of business. Only 12% still survive. Similar percentages are found throug...
As you know, enterprise IT conversation over the past year have often centered upon the open-source Kubernetes container orchestration system. In fact, Kubernetes has emerged as the key technology -- and even primary platform -- of cloud migrations for a wide variety of organizations. Kubernetes is critical to forward-looking enterprises that continue to push their IT infrastructures toward maximum functionality, scalability, and flexibility. As they do so, IT professionals are also embr...
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...
As you know, enterprise IT conversation over the past year have often centered upon the open-source Kubernetes container orchestration system. In fact, Kubernetes has emerged as the key technology -- and even primary platform -- of cloud migrations for a wide variety of organizations. Kubernetes is critical to forward-looking enterprises that continue to push their IT infrastructures toward maximum functionality, scalability, and flexibility.
Today's workforce is trading their cubicles and corporate desktops in favor of an any-location, any-device work style. And as digital natives make up more and more of the modern workforce, the appetite for user-friendly, cloud-based services grows. The center of work is shifting to the user and to the cloud. But managing a proliferation of SaaS, web, and mobile apps running on any number of clouds and devices is unwieldy and increases security risks. Steve Wilson, Citrix Vice President of Cloud,...