Book Image

Apache OFBiz Development: The Beginner's Tutorial

By : Jonathon Wong, Rupert Howell
Book Image

Apache OFBiz Development: The Beginner's Tutorial

By: Jonathon Wong, Rupert Howell

Overview of this book

<p>Apache OFBiz (Open For Business) is versatile open-source enterprise automation software that powers many small and medium sized businesses around the world. It incorporates a number of mature applications such as ERP, e-Commerce, MRP and CRM.<br /><br />Built around an MVC framework with common logic, data model and process components, Ofbiz allows existing and bespoke applications to be added through a component-based architecture. Ofbiz includes a mature suite of enterprise applications that integrate and automate a company's many business needs.<br />&nbsp;<br />This easy-to-read book will quickly enable newcomers to get hands-on with OFBiz. It provides an overview of the main modules and employs illustrated examples that show readers how to build exemplary business applications rapidly. Covering the main aspects of the Model-View-Controller framework, the reader will gain a working knowledge of Widgets, Entities, and The Service Engine. The authors also describe how to tweak OFBiz, and offer valuable performance and development tips. By navigating through the flow of OFBiz and providing insight into the thousands of examples that already exist in the core code they have made this book a must-have for anyone looking to get started with OFBiz.</p>

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Apache OFBiz Development: The Beginner's Tutorial
Jonathon Wong | Rupert Howell
Oct, 2008 | 472 pages
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Table of Contents (20 chapters)
Apache OFBiz Development
Apache OFBiz Development
Credits
Credits
About the Authors
About the Authors
About the Reviewers
About the Reviewers
Preface
Preface
Free Chapter
1
Getting Started with OFBiz
Getting Started with OFBiz
Getting the OFBiz Code
Downloading and Installing SVN
Installing the Java Development Kit (JDK)
Downloading OFBiz Ready to Launch
Setting Up an Eclipse Project
Using Derby—the OFBiz Stock Database
Running OFBiz
Switching Off OFBiz
Our First Tour of OFBiz
Summary
2
Working with OFBiz
Working with OFBiz
Adding Our First Field
Resetting Our Play Area Quickly
The Structure of OFBiz in General
The Model-View-Controller Architectural Pattern
Summary
3
Screen Widgets
Screen Widgets
Equipping Our Webapp with a Screen Widget View Handler
Using the Screen Widget View Handler
Files and Locations
Creating Our First Screen Widget
The Anatomy of the <section> Element
Nested Sections for Nested Conditions
Organizing a Large Screen into Smaller Screens
Screen Widget's Integration with FreeMarker
Cleaning Up in the "party" Component
Commenting Changes to the Core Code
Screen Widgets as Templates
Summary
4
Form Widgets
Form Widgets
Files and Locations
Creating Our First Form Widget
Form Processing via Request Event
Java Events
Submitting and Processing Our First Form
The "list" Type Form Widget
The "multi" Type Form Widget
Alternative Targets in Two-Target Forms
Row-Level Actions
Summary
5
Other View Element Types in Screen Widgets
Other View Element Types in Screen Widgets
Menu Widgets
FreeMarker
Bringing it All Together
Summary
6
The Controller
The Controller
How OFBiz Hears Our Requests—The Control Servlet
Programming a Control Servlet
Summary
7
Entities, View Entities, and Extended Entities
Entities, View Entities, and Extended Entities
Entities
View Entities
Extending Entities
Summary
8
Accessing the Entities and View Entities
Accessing the Entities and View Entities
Setting-Up Our Playground
GenericValue Objects
Creating a Database Record
Updating Database Records
Deleting Database Records
Retrieving Database Records
Using the Entity Engine Cache
Dynamic View Entities
Paginating Using the EntityListIterator
Functions and Dynamic View Entities
Summary
9
The Events
The Events
Java Events
Working with the Database
Summary
10
The Service Engine
The Service Engine
Defining a Service
Creating the Java Code for the Service
Testing Our First Service
Service Parameters
The DispatchContext
Service Security and Access Control
Calling Services from Java Code
Implementing Interfaces
Synchronous and Asynchronous Services.
Using the Job Scheduler
Quickly Running a Service
Naming a Service and the Service Reference
Event Condition Actions (ECA)
Summary
11
Permissions and the Service Engine
Permissions and the Service Engine
Simple Permissions
Two-Part Permissions and Special "_ADMIN" Permissions
Role Checks
Combining Multiple Checks
Nested Checks
Complex Permissions
Summary
12
Minilang
Minilang
What is Minilang?
Defining a Simple Service
Simple Events
Validating and Converting Fields
Checking Security in Minilang
Invoking from Minilang
Minilang in Screen Widgets
Summary
13
Tying Up the Loose Ends
Tying Up the Loose Ends
The OFBiz Look and Feel
Using FreeMarker
OFBiz Utilities
Outputting Different Formats
Summary
14
Tips and Techniques
Tips and Techniques
Debugging Techniques
Debugging Java Code
Managing a Project Using Subversion
Apache HTTP Server and OFBiz using mod_proxy_ajp
Development Tips
Summary
Simple Method User's Guide
Simple Method User's Guide

Using the Entity Engine Cache

OFBiz has a really neat feature that, if used correctly, can drastically increase the application's performance by dramatically cutting down the number of queries sent to the database. It does this by using what is known as the Entity Engine Cache. The principle of a cache is to act as an easily accessible store of data. This store is first checked and if the required data is there then it is retrieved immediately. If the required data is not present in the cache then it is obtained, in the case of the Entity Engine Cache, via a database lookup. The data is then placed into the cache. The next time the same information is required, the cache is again checked and the data is returned immediately from the cache.

Since the cache is held in memory, the lookup is now performed much faster.

Using the cache is easy. Where we would normally use the GenericDelegator object's findByPrimaryKey() method to return one record, we use findByPrimaryKeyCache(). The Cache appendage...

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