I'm trying to generate Java code from an existing hbm.xml file.

I've read Chapter 4 of the reference documentation, amongst many other documents.
Unfortunately, I'm still totally cluesless as to the relationship between the hibernatetool and hbm2java Ant tasks.

My Ant file is currently as follows:

<taskdef
name="hibernatetool"
classname="org.hibernate.tool.ant.HibernateToolTask"
classpathref="libraries"/>

<taskdef
name="hbm2java"
classname="org.hibernate.tool.ant.Hbm2JavaExporterTask"
classpathref="libraries"/>

<target name="codegen">
<hbm2java output="${gensrc.dir}">
<fileset dir="${gensrc.dir}">
<include name="Centre.hbm.xml"/>
</fileset>
</hbm2java>
</target>

This seems to be the approach that is recommended for 2.1 but it's not clear to me just how beta 3.1 currently is.

I get the following error:

...build.xml:62: Could not create type hbm2java due to java.lang.NoSuchMethodException: org.hibernate.tool.ant.Hbm2JavaExporterTask.<init>(org.apache.tools.ant.Project)


Could someone kindly tell me where I'm going wrong please.

Many thanks
David

read the docs at tools.hibernate.org

I was hoping for something rather more constructive than this.

I read the relevant documents I could find. In particular chapter 4 of the reference guide. A simple example of how to do something simple would be very helpful.

Did you actually try and go to tools.hibernate.org and read the docs ?

afaik we don't have any hbm2java explanation in chapter 4 of the core reference guide it is all in the *tools* doc.

Yes I have.

The Chapter 4 I'm referring to is in the Hibernate Tools Reference - Ant Tools.

It leads me to suspect that my Ant file should look something like the following:


============
<?xml version="1.0" encoding="UTF-8"?>

<project basedir="." default="compile" name="connectHub-build">

<property name="src.dir" value="${basedir}/src"/>
<property name="mappings.dir" value="${basedir}/mappings"/>
<property name="gensrc.dir" value="${basedir}/gensrc"/>
<property name="config.dir" value="${basedir}/config"/>
<property name="dest.dir" value="${basedir}/classes"/>
<property name="libs.dir" value="${basedir}/libs"/>

<path id="hibernate.tools.libraries">
<fileset dir="${libs.dir}">
<include name="hibernate-tools.jar"/>
<include name="hibernate3.jar"/>
<include name="commons-logging-1.0.4.jar"/>
<include name="dom4j-1.6.1.jar"/>
<include name="commons-collections-2.1.1.jar"/>
<include name="ojdbc14.jar"/>
<include name="velocity-1.4.jar"/>
<include name="velocity-tools-generic-1.1.jar"/>
<include name="jtidy-r8-21122004.jar"/>
</fileset>
</path>


<target name="copy-resources">
<copy todir="${dest.dir}">
<fileset dir="${mappings.dir}">
<include name="**/*.hbm.xml"/>
</fileset>
<fileset dir="${config.dir}">
<include name="hibernate.cfg.xml"/>
</fileset>
</copy>
</target>

<taskdef
name="hibernatetool"
classname="org.hibernate.tool.ant.HibernateToolTask"
classpathref="hibernate.tools.libraries"/>

<taskdef
name="hbm2java"
classname="org.hibernate.tool.ant.Hbm2JavaExporterTask"
classpathref="hibernate.tools.libraries"/>

<target name="codegen" depends="copy-resources">
<hibernatetool destdir="${gensrc.dir}">
<classpath refid="project.classpath"/>
<configuration configurationfile="${config.dir}/hibernate.cfg.xml">
<fileset dir="${mappings.dir}">
<include name="Xxx.hbm.xml"/>
</fileset>
</configuration>

<!--<hbm2doc></hbm2doc>-->
<hbm2java jdk5="true" ejb3="false"/>
</hibernatetool>
</target>

</project>
============

But this fails with the bizarre error that:

class Xxx not found while looking for property: xxxSID

which in turn is caused by:

ClassNotFoundException: Xxx

which is rather odd as I have manually created Xxx.hbm.xml from which I'm trying to generate Xxx.java and then Xxx.class.

The Xxx.hbm.xml file:


===========
<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >

<hibernate-mapping>

<class
name="Xxx"
table="XXX">
<meta attribute="class-description">
Javadoc for the Xxx class
@author David Franklin
</meta>
<id name="xxxSID" column="SID">
<generator class="sequence">
<param name="sequence">XXX_SEQ</param>
</generator>
</id>
</class>

</hibernate-mapping>
===========

Something somewhere is going very wrong and I have spent several days going round in circles with this.
I would greatly appreciate some specific suggestions as to what the problem might be.

I am using Hibernate 3.1 and the latest Hibernate Tools beta.

David

Where in that doc do you see something that states this is needed:



?

In any case the error occurs because your mapping files does not contain any time information. (e.g. type="xxx" on <id>, <property> etc.)

/max

I had, perhaps incorrectly, assumed that I needed to do a taskdef for both hibernatetool and hbm2java.
If I remove the hbm2java task I then get the complaint that it can't read the mapping document but this still seems to be caused by the ClassNotFoundException I had previously.

Regarding the required contents of the Ant script, is there a working example anywhere - my sole source of information at the moment is the rather terse Chapter 4 in the Tools Reference.

Could you explain what you mean by the need for "time information" in a mapping file. I have other mapping files with no "time information" in them that work for standard CRUD operations = it's the code generation that is defeating me.

David

sorry a typo.

*type* information. If there is no type information how should hbm2java know which type you want it to generate ? :)

regarding examples i'll try and add one to the doc in the near future (otherwise look in the unit tests of hibernate tools)

I was basing my hbm.xml file on listing 2.2 in HIA - this doesn't specify a type and I thought I'd read that Hibernate tries to infer types where needed (not that I would expect to be able to rely on that). Having specified the type I now get my Java class generated. Hooray. But the error messages I was getting were rather unhelpful given the actual source of the problem.

An example added as part of the documentation would certainly be very helpful - and it might reduce such questions in the future!

Thanks
David

Hibernate != Hibernate Tools code generation - and what information should we use to infer the type when doing the actual code generation ?

I'll try if i can make the error message more clear.

Like I said, I wouldn't expect to rely on type interence. But its absence leads one down a very confusing path - a more informative/relevant error message would have saved a lot of pain.

Hi,

I have to agree: while it is obvious that a "type" attribute is required once being told so, i think it would not hurt to have hbm2java spit out an error indicating that attribute is missing. I wasted some time finding this out as well.

Nicolas