Netbeans + Visual Paradigm = EJB Tutorial

The only commercial product in my toolbox is Visual Paradigm, a professional UML and modeling tool that integrates with the Netbeans IDE. If you are sincere about ERD, Use-Case and class models you should look at it. The available Netbeans plugins for UML could not convince me yet, too simple (but free). Visual Paradigm seems to operate at the other end, looks rather overloaded with functionality, but once you know what you want and where the function is located, you can create a nice workflow.

In this tutorial (created for internal purpose) I share the steps to create an EJB and  the ERD model and let VP (Visual Paradigm) create the class source code for me.

Requirements:

• Netbeans 7.x
• Visual Paradigm (Professional Version)
  You can download the 30 days trial, the free community edition is not sufficient.

Tutorial Part 1:

• Create EJB module ‘demoejb’
  

  New EJB module

  

  New EJB module

  

  New EJB module

• Create the VP project file
  If you have properly integrated NB and VP you should see this additional buttons
  

  Integration

  Select the file view, select the project and click the VP icon
  (It makes a difference ! If you select the project in the projects explorer and click the VP icon the file gets created under /src/vpproject and the code creation fails later on, not sure if this is a feature or a bug as of VP version 5.2)

  

  Starting VP

• Create a ERD diagram with our DB table layout
  For this sample we will use the simple name-address sample
  customer_name and customer_address (the tables are not complete, rather a base for the demo walk-through)
  We use a UUID in all tables as primary key.
  

  ERD

  customer_name
  primary key: pk_customer_name

  

  customer_name

  customer_address
  primary key: pl_customer_address

  

  customer_address

  Create a one-to-many relationship
  Click the ‘one-to-many’ tool, then drag from customer_name to customer_address, and enter:
  fk_customername_customeraddress as new column for the relationship

  

  Relationship Mapping

  

  Create column

  Resulting ERD

  

  ERD

• Create classdiagramm
  

  ORM

  

  Class Diagram (default)

  Change the stereotype to entity bean for both classes

  

  Stereotype

  Final Class Diagram

  

  Class Diagram

   

• Synchronize with Netbeans (code creation)
  

  Sync with NB

  Created package and classes

  

  Code Creation

  There is a bug in the code creation, the imports dont get properly created (as in current version 5.2)

  

  Import Problem

  Fix the problem manually by importing
  import java.sql.Date;
  import java.sql.Timestamp;

  You can check the Netbeans Settings in VP
  

  

  NB settings in VP

  
  

• Add Eclipse library to project
  (we need for JPA queries at a later stage)
  

  Eclipse Libraries

• Create Meta Model
  Just clean and build will result in meta class created.
  

  Meta class

• Create Persistence Unit ‘demoejbPU’
  For now we use the default sample DB
  

  Create PU

  

  Create PU

   

• Create Session Bean for Entity Class
  in package facade
  

  Session Bean

  

  Session Bean

   

• Final project structure
  

  Project Structure

   

• Deploy the EJB
  The tables get created (depending on your PU strategy)
  

  Database

Remarks:

• Even VP supports round-trips, means changes in the EJB class can be sync’d back to your VP project, I prefer to maintain all DB changes in VP and recreate class diagram and classes, you better dont touch the class asit gets overwritten.
• Be careful with deletions and name changes of columns, they are not ‘forwarded’ to your already existing classes (source code).

In Part 2 we will create a ZK client web application and tinker with different DB’s (Oracle and PostgreSQL). Stay tuned.

Advertisement