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ERP 2.50:Developers Guide/Main Development Concepts

ERP 2.50:Developers Guide



Design principles

Openbravo ERP is a software application which is being developed with the following design principles in mind:

The aim of Openbravo is, while following these principles, to deliver an application which is state-of-the-art from both a technological as well as a functional point of view.

Open Source

Openbravo is an open source project built on open source technologies. We aim to leverage on the excellent infrastructure components developed by the open source community to ensure our platform benefits from the advantages and stability of components supported by a large community. Whenever necessary we contribute our developments back to the community.

ERP application framework

Openbravo ERP is an application developed through an integrated development framework included in Openbravo ERP distribution. This integrated development framework takes care of a wide range of concerns in all the areas involved during the development process. Most relevant from low level to high level:

Model Driven Development

Openbravo ERP follows a Model Driven Development (MDD) approach. This means that Openbravo uses a technology agnostic model to define application components, such as windows and processes. Based on this application model, java code and other software artifacts are generated.

Openbravo model information -so called metadata- is stored in the Openbravo Application Dictionary. The process to generate the code from metadata is called Wizard for Application Development (WAD).

Model Driven Development aims to increase productivity and re-use through separation of concerns and abstraction. The model is an abstract definition of system components which contains enough information to drive the generation of one (or more) implementations of the system in a concrete technology.

This separation of concerns -abstract functional description in the model and implementatation of model components in a concrete technology- hides technology complexities to ERP domain experts in their process to define and implement new ERP functionality and simplifies the evolution of the implementation technology

In some cases it is needed to code a solution externally from the model. This is fully supported by Openbravo. Developers can freely develop their own solutions on top of the Openbravo ERP technology stack.


Modularity is a new capability introduced in the Openbravo ERP 2.50 release which allows to define and package additional functionality and configurations as extension modules, independently from the core product.

Modularity changes the way in which Openbravo ERP can be adapted to user needs. Instead of customizing the code to match user requirements, it is possible to externally -from an independent module- extend Openbravo ERP functionality and to configure it.

This new approach has several advantages. Most important:

Pure web application - Rich client

Openbravo ERP is, by its very nature, a pure web application. Ubiquity of web browsers provides an universal point of access. Openbravo understands the network as a platform, delivering and allowing users to use applications entirely through a browser.

The requirements are minimum: a web browser is available on virtually all computer systems. Moreover, being web-based means the product can be delivered over the Internet, allowing to update the application without distributing and installing software on potentially hundreds of client computers.

Traditionally web applications had big limitations in regards of user interface. This has changed with the introduction of new web technologies such as AJAX. With AJAX and similar frameworks it is possible to develop a rich, interactive and user-friendly interface

Java - Lightweight J2EE

Openbravo uses Java as its backend programming language. There are many reasons for choosing Java as the server-side language:

Openbravo follows Java 2 Enterprise Edition architecture (J2EE) without making use of the EJB container. Instead of that Openbravo uses lightweight infrastructure to implement access to data and business logic. In Openbravo 2.50 Openbravo has delivered a new Data Access Layer (DAL) based on Hibernate that provides a powerful but still lightweight persisting mechanism.

Support for multiple databases

Openbravo is committed to avoid vendor locking in any technology it uses including database. In Openbravo 2.50 Openbravo runs on PostgreSQL (8.3) and Oracle SE (10g-11g).

In future releases Openbravo aims to be database independent. The new Data Access Layer (DAL) based on Hibernate is a first step in that transition

Openbravo main concepts

System requirements

Openbravo runs on top of a group of well-known third party applications:

All of these applications can be installed both on Linux or Windows.

Development Environment

Openbravo developers have three different ways to develop their code. Following the MDD approach, most common is to edit Openbravo Application dictionary through a web browser connected to Openbravo ERP. Based on the new model definition the software artifacts can be generated automatically. A developer can also connect directly to the Openbravo database through a sql client (eg. pgAdmin, sqlDeveloper) to manage database schema objects (tables, procedures, etc.). Finally developers can develop their own code through an integrated development environment such as Eclipse.

OpenBravo development environment

All openbravo software artifacts are stored in text files in the development project. This includes the database definition and content. The large advantage of using text files for storing all software artifacts is that it is much easier to share and compare changes made by developers in a distributed environment.

Openbravo uses a tool called DBSourceManager to manage database source code. DBSourceManager is able to read from the database schema objects and application dictionary data and export them to xml files. It can also create or update an Openbravo database from those xml files

The process to build the system from openbravo source code includes a number of steps to generate the code at different levels (DAL, WAD and others) and put together that code with other code directly written by developers. Openbravo has automated this process through an ant task.

Build and deploy process

The automation of code generation is achieved by using the Application Dictionary and the WAD (Wizard for Application Development). WAD automatically generates all the files of the application with an MVC architecture using Openbravo MVC framework

MVC Foundation Framework (MVC-FF)

The Openbravo web user interface follows a model-view-controller approach. Openbravo uses an advanced runtime generation and templating technology (MVC-FF) to generate the user interface (the html page) on request.

MVC-FF is composed of a set of utilities developed by Openbravo: XmlEngine, SQLC and HttpBaseSecureServlet. MVC-FF is needed to allow the development of decoupled files for the Model, View and Control components of the MVC architecture.

This set of utilities has been used in the development of many other MVC applications, and it has proven to be very efficient for the Openbravo development team


XmlEngine is a utility used to create XML/HTML documents from a template in XML/HTML format and an XML configuration file with the dynamic data to be inserted in the template.

XmlEngine is easy to use because the design of the template is the identical to that of the final document desired. The input of data is made identifying the places where data will be displayed by using standard XML/HTML attributes like “id” or tags such as “DIV”. The configuration file maps the data source fields with the places identified in the template. To improve performance, the templates are read and stored in memory.

When a page is required, the template creates a document and fills it with data. The XmlEngine tool is responsible for generating the forms for editing a record, list a selection of records, create reports with grouping levels or print specific forms of the application.

The XmlEngine is described in more detail on this page.


SQLC (SQL Compiler) is a utility used to avoid the repetitive task of writing Java classes to interact with the database. The input is an XML file that contains standard SQL statements and the parameters used in the statements. SQLC reads this file and generates a Java class that has all the code necessary to connect to the database, execute the statement, read the record and create standard Java types as return for the methods.


HttpBaseServlet and HttpBaseSecureServlet are the servlets from which all of the servlets of the system that implement the Control component of MVC are derived. These servlets implement common functionalities such as authentication, authorization, database connectivity and error handling. The servlets deriving from HttpBaseSecureServlet make the standard control of reading data, interacting with the database with classes generated by SQLC and providing the output with XmlEngine. For more information on the Openbravo base servlet structure visit this page.

Data Access Layer (2.50)

In the 2.50 release a new component has been added to the Openbravo Architecture: the Data Access Layer (DAL). The DAL uses hibernate to make Openbravo entities and business objects available to the Java developer.

The DAL provides the application developer with the following functionality:

The DAL consists of a development-time and runtime part. The development-time part takes care of generating Java business object classes. The runtime part takes care of mapping Java classes to the database and supporting functionality such as querying, security and validation.

For more information about the Data Access Layer please visit this page.

ERP 2.50:Developers Guide/Development Environment/Setting up Development Environment with Eclipse IDE | ERP 2.50:Developers Guide/What's new 

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