Seam Tip Number 3

Seam Tip Number 3

This isn't so much a tip, but a "gotcha" to avoid.

Make sure that you have an <h:messages /> tag in your page and that it does not have "globalOnly" set to "true."

I spent a lot of time wondering my my method wasn't getting called when the problem was a not null value being trapped.

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Seam Tip Number 2

Seam Tip Number 2

Keep insert statements inside the import.sql file on the same line.

One of the coolest things about developing in Seam is the "create-drop" setting for data. 

If you create your project with seam-gen and choose "y" for the prompt, "Do you want to drop and recreate the database tables and data in import.sql each time you deploy?" there will be three files, import-dev.sql, import-test.sql and import-prod.sql.  The data in these files will be used to populate tables generated from your entities.  You can of course do this manually, but I want to be brief.

I mocked up some data and redeployed, but I wasn't seeing anything when I hit the page.  Watching the log files after restarting the server showed an sql error on import which turned out to be the line break.  I was using Eclipse to edit the file so I found that odd, but stranger things have of course happened.  I removed the line breaks and everything worked.

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Seam Tip Number 1

Seam Tip Number 1

Seam-gen saves your defaults in the build.properties (Ant of course) file inside the [Seam dist]/seam-gen folder. 

If like me you have accidentally typed the wrong directory for your project workspace or the wrong directory for your db driver jar file, simply edit the build.properties and the defaults will change.


Seam-gen is a cool part of JBoss Seam.  From the Seam docs,
"This is the easy way to get your feet wet with Seam, and gives you some ammunition for next time you find yourself trapped in an elevator with one of those tedious Ruby guys ranting about how great and wonderful his new toy is for building totally trivial applications that put things in databases."

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Code is design

Everyone has heard the line, "The older I get the more I realize my father was right."  This a cliche of course, but I'm reminded of it pretty often now that I have kids of my own.

The Too Much Code blog, which I found on DZone this morning, reminded me of this.  Unless I have a selective memory, more selective than the average anyway, I remember hearing that we developers needed a complete design before we started coding.  I still hear that a lot actually despite the success of Pragmatic Programmers, XP, Scrum, etc.

I don't remember people telling me that big up front software design was a bad idea, and the older that I get the more I think it is at best a waste of time and worst a serious project risk.

From Too Much Code :
"If we accept that code is design -- a creative process rather than a mechanical one -- the software crisis is explained. Now we have a design crisis: the demand for quality, validated designs far exceeds our capacity to create them. The pressure to use incomplete design is strong."

From the articles (same link as in the quote) that he references,
"We must keep in mind, however, that these tools and notations (UML, CRC Cards, Booch diagrams) are not a software design. Eventually, we have to create the real software design, and it will be in some programming language. Therefore, we should not be afraid to code our designs as we derive them."

Too bad my father never told me anything about software development.

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Seam Lifecycle

I've been playing with JBoss' Seam for a brief while now. I've used Struts for years so I'm completely familiar with its' action based lifecycle. I have considerably less experience with JSF. Knowing a framework's lifecycle is definitely useful, and I wanted a diagram of Seam's.

This article from IBM Developerworks has a gif diagram that nicely outlines Seam's enhancements to the JSF lifecycle. I printed it out and tacked it onto my cube.

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Seam-gen and TestNG problems

I created a project using Seam-gen, taking the database defaults (I wanted hsqldb for development anyway.)

First thing I wrote a test for the Manager/Action class that I was starting with. I also added a testng.xml to the src/test folder. I was using Eclipse so I right clicked on the build.xml's test target and ran it. Nothing.

The testng.xml file wasn't get copied to the test-build directory so I updated the build.xml withe the following :

• test target - changed line 315 to read <xmlfileset dir="${test.dir}" includes="testng.xml" /> instead of <xmlfileset dir="${test.dir}" includes="*Test.xml" />
• copytestclasses target - added <include name="*.xml" /> in the last copy statement so that the testng.xml file was copied from classes/test directory along with the class files
• copytestclasses target - removed "if='eclipse.running'" from the target. I don't know why, but the files weren't copied at all with this qualifier even though I was running out of Eclipse.

The test ran from build.xml.

Right clicking and running the TestNG plugin didn't do anything though. I opened the Run dialog (Run -> Open Run Dialog) and updated the classpath of the TestNG test to include the lib/test folder and ran the test from there. I got a different but no better result. (The stack trace is pasted below in the possibly vain belief that someone may stumble onto this posting while Googling the same problem)

javax.persistence.PersistenceException: org.hibernate.HibernateException: The chosen transaction strategy requires access to the JTA TransactionManager
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:737)
at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:121)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:83)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:60)

I found this entry on JBoss' Forums which suggested using a non-jta-data-source in the persistence-test.xml. I updated my persistence-test.xml to the following (changes in bold) :

<?xml version="1.0" encoding="UTF-8"?>
<!-- Persistence deployment descriptor for tests -->
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
version="1.0">

<persistence-unit name="project_name" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<non-jta-data-source>java:/DefaultDS</non-jta-data-source>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
<property name="hibernate.hbm2ddl.auto" value="create-drop"/>
<property name="hibernate.show_sql" value="true"/>
<property name="jboss.entity.manager.factory.jndi.name" value="java:/project_nameEntityManagerFactory"/>
</properties>
</persistence-unit>

</persistence>

That did the trick; although, it doesn't appear that my test data is getting loaded. I'll blog that solution later.

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Seam and TestNG and a missing rar file

Generated a new project with seam-gen.

Had a problem with the build.xml's "test" task. I got the error "You need to specify at least one testng.xml or one class"

I downloaded last night's snapshot from JBoss. (On a side note, I've started using Hudson after seeing it used by JBoss, and its very nice. I like it more than Continuum and CruiseControl.) Same error.

I added a testng.xml file to src/test directory.

I changed buildxml :
added "<include name="**/*.class"/>" to line 282
added "<copy tofile="${test.dir}/testng.xml" file="${src.test.dir}/testng.xml" overwrite="true"/>" to line 296.
changed line 320 (324 after adding the above) to "<xmlfileset dir="${test.dir}" includes="testng.xml" />"

The test ran, which was good; however, there were errors in the output.
"Error parsing meta data jboss-local-jdbc.rar"

Looking through the output I noticed that there was an io.FileNotFound for "C:\Documents%20%and%20%Settings." The actual file was referenced correctly in several of the other lines, but I decided to start over with seam-gen and put the folder directly on the C drive with no spaces.

It worked.

The moral : put my Eclipse workspaces on the C drive.

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