THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
Article donated by: Leonard Flournoy, Hernan Cunico
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An entity bean is defined as a representation of persistent data that has the ability to read from database and populate its fields with data. It can be updated and stored back to the database. There are two types of entity beans: Bean-Managed Persistence(BMP) and Container-Managed Persistent(CMP). This article covers an example of a CMP, more specifically, a CMP application migration. For this type of entity bean, actual code must be written to handle persistent operations such as loading, saving and finding data. The developer must use persistence API such as JDBC to select, insert, update, delete from a database.
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CMP implementation may vary from one vendor to another. The purpose of this section is to provide a CMP specific feature-to-feature comparison between JBoss v4 and Apache Geronimo M5 so you can clearly identify the differences and plan accordingly before migration.
Feature | JBoss v4 | Apache Geronimo M5 |
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EJB Container | JBoss AS 4.0 comes with its own EJB Container implementation. | Geronimo uses OpenEJB as its EJB Container. |
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Sample application
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The Loan CMP Sample application is very simple. When the command line client is run, an entry is made into the database. The findByPrimaryKey() method of the CustomerHomeRemote interface is called and the field values of the returned CustomerRemote object are printed to the console. This is followed by a call to the findBySssNo() method after which the field values of the returned CustomerRemote object are printed to the console.
The following figure illustrates the application flow:
The user runs the command line client which then either creates an entity bean (which then adds itself to the datasource) or asks for one, by primary key, which is created from information that is stored in the database.
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In order to build the loan application a Maven script has been provided. Download the Loan application from the following URL:link:
Loan CMP Samplehttp://opensource2.atlassian.com/confluence/oss/download/attachments/1146/cmp.zip
After extracting the zip file, a loan-cmp directory will be created. From now on, this directory will be referred as <cmp_home>. In that directory open the project.properties file. Edit the maven.jboss.home property to match your environment. It is important that you use "//" on the windows platform as is done below.
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You should see the following screen:
Click on Add Customer. Enter the new customer information then click Create, this will take you to the first page showing the updated list of customers.
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CREATE TABLE CUSTOMER(ID INTEGER NOT NULL PRIMARY KEY,NAME VARCHAR(45),BIRTHDATE DATE,SSS_NO VARCHAR(25),ADDRESS VARCHAR(60),ANNUAL_SALARY DOUBLE,LOAN_AMOUNT DOUBLE)
Configure Maven
You should set the maven.geronimo.home property in project.properties to point to your <geronimo_home> directory.
Step-by-step migration
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<?xml version="1.0" encoding="UTF-8"?>
<openejb-jar
xmlns="http://www.openejb.org/xml/ns/openejb-jar"
xmlns:naming="http://geronimo.apache.org/xml/ns/naming"
xmlns:security="http://geronimo.apache.org/xml/ns/security"
xmlns:sys="http://geronimo.apache.org/xml/ns/deployment"
configId="CustomerEJB"
parentId="orggeronimo/apache/geronimo/SystemDatabasesystem-database/1.0/car">
<enterprise-beans>
<entity>
<ejb-name>CustomerEJB</ejb-name>
<jndi-name>CustomerHomeRemote</jndi-name>
<local-jndi-name>CustomerRemote</local-jndi-name>
<resource-ref>
<ref-name>jdbc/ibm-demo</ref-name>
<resource-link>SystemDatasource</resource-link>
</resource-ref>
</entity>
</enterprise-beans>
</openejb-jar> |
This plan sets orggeronimo/apache/geronimo/SystemDatabasesystem-database/1.0/car as the parent. What follows is the definition of the entity bean. The jndi-name element indicates the jndi name of the entity bean's home interface CustomerHomeRemote. This is the name that the Loan CMP sample application will lookup in the jndi context. The element local-jndi-name indicates the jndi name of the local interface, which in this case happens to be a remote interface, CustomerRemote. Next, a reference to the SystemDatasource is defined giving the application access to the database.
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