ClassCastException using hbm2java.CodeGenerator with meta

jeskandarian · **Posted:** Sat Oct 18, 2003 11:04 am

When using net.sf.hibernate.tool.hbm2java.CodeGenerator, if I use any meta tags in the mapping file, I get a ClassCastException when running the codegen. If I comment out all meta tags, it works fine.

I'm using v2.0.3 of the hibernate.jar and v2.1 of the hibernate tools.

It seemed I had to build the hibernate-tools.jar locally to get the hbm2java class in the hibernate-tools.jar. Maybe this is my problem??

Is there a version of the hibernate-tools.jar that includes the hmb2java?
Thanks in advance for any help...

Here's the mapping with a single meta tag UNcommented:

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>


   <meta attribute="extends">com.medengineering.bus.vo.HibernateVOImpl</meta>
   <!--meta attribute="implements">com.medengineering.bus.vo.HibernateVO</meta-->
   <class name="com.medengineering.bus.vo.CatalogItemVO"
        table="catalog_item">
      <!--meta attribute="class-description">
         Items for the catalog
         @author jay
      </meta-->
      <id name="id" type="long">
         <generator class="increment"/>
      </id>
      <property name="catalogItemName" type="string">
         <!--meta attribute="field-description">
            The item's name as will be displayed in search results etc.
         </meta-->
      </property>
      <property name="descLong" type="string">
         <!--meta attribute="field-description">Long description. May contain HTML.</meta-->
      </property>
      <many-to-one name="category" column="category_id"
               class="com.medengineering.bus.vo.CatalogCategoryVO">
      </many-to-one>
      <set name="images" inverse="true">
         <key column="catalog_item_id"/>
         <one-to-many class="com.medengineering.bus.vo.CatalogImageVO"/>
      </set>
   </class>

   <class name="com.medengineering.bus.vo.CatalogCategoryVO"
         table="catalog_category">
      <!--meta attribute="class-description">Category</meta-->
      <id name="id" type="long">
         <generator class="increment"/>
      </id>
      <property name="categoryName" type="string">
         <!--meta attribute="field-description">short category name</meta-->
      </property>
      <property name="parentId" type="java.lang.Long" column="parent_id" insert="false" update="false"/>
      <set name="catalogItems" inverse="true">
         <key column="category_id"/>
         <one-to-many class="com.medengineering.bus.vo.CatalogItemVO"/>
      </set>
      <set name="subCategories" inverse="true" >
         <key column="parent_id"/>
         <one-to-many class="com.medengineering.bus.vo.CatalogCategoryVO"/>
      </set>

      <many-to-one  name="parentCategory" column="parent_id" class="com.medengineering.bus.vo.CatalogCategoryVO" >

      </many-to-one>

   </class>

   <class name="com.medengineering.bus.vo.CatalogImageVO"
        table="catalog_image">
      <id name="id" type="long">
         <!--meta attribute="scope-set">
            protected
         </meta-->
         <generator class="increment"/>
      </id>
      <property name="imageType" type="int"/>
      <property name="description" type="string">
         <!--meta attribute="field-description">
            Some description of the image
         </meta-->
      </property>
      <property name="imagedata" type="blob"/>
      <many-to-one name="parentItem" column="catalog_item_id" class="com.medengineering.bus.vo.CatalogItemVO"/>
   </class>
</hibernate-mapping>

Here's the stack trace:

Code:

java.lang.ClassCastException
   at net.sf.hibernate.tool.hbm2java.MetaAttributeHelper.mergeMetaMaps(MetaAttributeHelper.java:89)
   at net.sf.hibernate.tool.hbm2java.MetaAttributeHelper.loadAndMergeMetaMap(MetaAttributeHelper.java:110)
   at net.sf.hibernate.tool.hbm2java.ClassMapping.initWith(ClassMapping.java:86)
   at net.sf.hibernate.tool.hbm2java.ClassMapping.<init>(ClassMapping.java:73)
   at net.sf.hibernate.tool.hbm2java.CodeGenerator.main(CodeGenerator.java:99)

Here's the ant target:

Code:

<target name="codegen-catalog" description="generate the VO code for the catalog">
      <java classname="net.sf.hibernate.tool.hbm2java.CodeGenerator"
             fork="true"
             failonerror="true">
         <classpath>
            <path refid="base.path"/>
         </classpath>
         <arg value="--output=${src.java}"/>
         <arg value="${conf.dir}/hibernate-catalog-map.hbm.xml"/>

      </java>
   </target>

jeskandarian · **Posted:** Sat Oct 18, 2003 12:58 pm

jdenly · **Posted:** Sat Mar 20, 2004 8:24 am

Hi,

I'm having the same issue with hibernate 2.1 and hibernate extensions 2.0.2. I have also built the cvs HEAD revision of hibernate-extensions and the error occurs in that version too. I am processing the hbm files generated using MiddleGen through ant and receive the following exception, (note the line numbers are slightly different in the cvs version, but it's the same exception):

Code:

 [hbm2java] java.lang.ClassCastException
 [hbm2java]     at net.sf.hibernate.tool.hbm2java.MetaAttributeHelper.mergeMetaMaps(MetaAttributeHelper.java:89)
 [hbm2java]     at net.sf.hibernate.tool.hbm2java.MetaAttributeHelper.loadAndMergeMetaMap(MetaAttributeHelper.java:110)
 [hbm2java]     at net.sf.hibernate.tool.hbm2java.ClassMapping.initWith(ClassMapping.java:160)
 [hbm2java]     at net.sf.hibernate.tool.hbm2java.ClassMapping.<init>(ClassMapping.java:72)
 [hbm2java]     at net.sf.hibernate.tool.hbm2java.CodeGenerator.handleClass(CodeGenerator.java:128)
 [hbm2java]     at net.sf.hibernate.tool.hbm2java.CodeGenerator.main(CodeGenerator.java:103)
 [hbm2java]     at net.sf.hibernate.tool.hbm2java.Hbm2JavaTask.processFile(Hbm2JavaTask.java:145)
 [hbm2java]     at net.sf.hibernate.tool.hbm2java.Hbm2JavaTask.execute(Hbm2JavaTask.java:95)
 [hbm2java]     at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:306)
 [hbm2java]     at org.apache.tools.ant.Task.perform(Task.java:401)
 [hbm2java]     at org.apache.tools.ant.Target.execute(Target.java:338)
 [hbm2java]     at org.apache.tools.ant.Target.performTasks(Target.java:365)
 [hbm2java]     at org.apache.tools.ant.Project.executeTarget(Project.java:1237)
 [hbm2java]     at org.apache.tools.ant.Project.executeTargets(Project.java:1094)
 [hbm2java]     at org.apache.tools.ant.Main.runBuild(Main.java:669)
 [hbm2java]     at org.apache.tools.ant.Main.startAnt(Main.java:220)
 [hbm2java]     at org.apache.tools.ant.Main.start(Main.java:184)
 [hbm2java]     at org.apache.tools.ant.Main.main(Main.java:267)

Here is an example of a hbm file that validates against the dtd and works fine if I comment out the meta tags:

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 2.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
    
<hibernate-mapping>
<!-- 
    Created by the Middlegen Hibernate plugin

    http://boss.bekk.no/boss/middlegen/
    http://hibernate.sourceforge.net/
-->

<class 
    name="jonnydee.nextgemeration.persistence.hibernate.Location" 
    table="location"
>
    <meta attribute="class-description" inherit="false">
       @hibernate.class
        table="location"
    </meta>

    <id
        name="locationid"
        type="java.lang.Long"
        column="locationid"
    >
        <meta attribute="field-description">
           @hibernate.id
            generator-class="assigned"
            type="java.lang.Long"
            column="locationid"

        </meta>
        <generator class="assigned" />
    </id>

    <property
        name="name"
        type="java.lang.String"
        column="name"
        not-null="true"
        length="64"
    >
        <meta attribute="field-description">
           @hibernate.property
            column="name"
            length="64"
            not-null="true"
        </meta>    
    </property>
    <property
        name="sortorder"
        type="int"
        column="sortorder"
        not-null="true"
        length="4"
    >
        <meta attribute="field-description">
           @hibernate.property
            column="sortorder"
            length="4"
            not-null="true"
        </meta>    
    </property>
    <property
        name="version"
        type="long"
        column="version"
        not-null="true"
        length="8"
    >
        <meta attribute="field-description">
           @hibernate.property
            column="version"
            length="8"
            not-null="true"
        </meta>    
    </property>

    <!-- associations -->
    <!-- bi-directional one-to-many association to Costcentrelocation -->
    <set
        name="costcentrelocations"
        lazy="true"
        inverse="true"
    >
        <meta attribute="field-description">
           @hibernate.set
            lazy="true"
            inverse="true"

          @hibernate.collection-key
           column="locationid"

           @hibernate.collection-one-to-many
            class="jonnydee.nextgemeration.persistence.hibernate.Costcentrelocation"
        </meta>
        <key>
            <column name="locationid" />
        </key>
        <one-to-many 
            class="jonnydee.nextgemeration.persistence.hibernate.Costcentrelocation"
        />
    </set>
    <!-- bi-directional one-to-many association to Employee -->
    <set
        name="employees"
        lazy="true"
        inverse="true"
    >
        <meta attribute="field-description">
           @hibernate.set
            lazy="true"
            inverse="true"

          @hibernate.collection-key
           column="locationid"

           @hibernate.collection-one-to-many
            class="jonnydee.nextgemeration.persistence.hibernate.Employee"
        </meta>
        <key>
            <column name="locationid" />
        </key>
        <one-to-many 
            class="jonnydee.nextgemeration.persistence.hibernate.Employee"
        />
    </set>
    <!-- bi-directional one-to-many association to Rolerelationshipmanager -->
    <set
        name="rolerelationshipmanagers"
        lazy="true"
        inverse="true"
    >
        <meta attribute="field-description">
           @hibernate.set
            lazy="true"
            inverse="true"

          @hibernate.collection-key
           column="locationid"

           @hibernate.collection-one-to-many
            class="jonnydee.nextgemeration.persistence.hibernate.Rolerelationshipmanager"
        </meta>
        <key>
            <column name="locationid" />
        </key>
        <one-to-many 
            class="jonnydee.nextgemeration.persistence.hibernate.Rolerelationshipmanager"
        />
    </set>

</class>
</hibernate-mapping>

Anyone else seen this problem or have any ideas? As far as I can tell from the cvs HEAD revision source, there is a problem with this cast at line 91 in net.sf.hibernate.tool.hbm2java.MetaAttributeHelper:

Code:

MetaAttribute element = (MetaAttribute) iterator.next();

Thanks in advance for any assistance.

Jon

jdenly · **Posted:** Sat Mar 20, 2004 9:28 pm

I've delved a bit further into this problem and it is caused by the MetaAttributeHelper being passed an ArrayList when it is expecting a MetaAttribute, hence the ClassCastException. I've added an extremely hacky workaround by modifying the MetaAttributeHelper line 91 as follows:

Code:

MetaAttribute element = (MetaAttribute)((ArrayList)iterator.next()).get(0);

This just extracts the first element from the ArrayList and uses that. Really this is only a workaround as the ArrayList shouldn't be passed in here, but it works for me. Luckily, all of the ArrayLists passed in for my classes only contain one element. Obviously this won't work if that isn't the case. After this change, hbm2java successfully finishes and the classes have the XDoclet tags in place :)

Regards,

Jon

max · **Posted:** Sun Mar 21, 2004 12:06 am

are you 100% sure that you have get this behavior when running from the head cvs version of hibernate-extensions ?

if yes - then submit a bug on it with a SIMPLE mapping file...

jdenly · **Posted:** Mon Mar 22, 2004 4:09 am

I've logged the bug with a simple test case. Issue number HB-829.

Cheers,

Jon

max · **Posted:** Mon Mar 22, 2004 4:24 pm

jdenly wrote:

I've logged the bug with a simple test case. Issue number HB-829.

Cheers,

Jon

yes - and i have now closed as a "cannot reproduce" since the problem ain't in the current cvs as i said !

Please check that the next time - ok ? ;)

/max

jdenly · **Posted:** Mon Mar 22, 2004 6:08 pm

I checked out from CVS the top level directory marked as HibernateExt - I guess that must be a link to the release version, not the current HEAD. Sorry to waste your time with something you've already fixed! Thanks for your efforts on this.

(Embarressed) regards,

Jon

retnuh · **Joined:** Mon Sep 08, 2003 6:52 am **Posts:** 46

So I'm a bit confused - I'm getting the same error with a
_really_ simple mapping file and hibernate-exetensions 2.0.2.

Is it a known problem in hibernate-extensions-2.0.2, but it's
been fixed in the CVS? If so, does that mean I need to
build the latest from CVS, or is there a release soon, or...?

Thanks,

Hunter

retnuh · **Joined:** Mon Sep 08, 2003 6:52 am **Posts:** 46

Sorry to reply to my own post, but I've tried to build
hibernate extensions from CVS, and I still get the error.

I've tried explicitly checking out with -r HEAD, and still get the same
thing. I've noticed that the build still produces directories with
2.0.1 in them, though.

which branch do I need to build from to get a working version?

it looks like v22branch version of MetaAttributeHelper.java is even older...

H

max · **Posted:** Tue Mar 23, 2004 1:52 pm

it is HEAD and i used the hbm.xml file that you had in the jira.

retnuh · **Joined:** Mon Sep 08, 2003 6:52 am **Posts:** 46

Actually, I'm a different person having the same problem :)

It's the latest cvs version (checked out with -r HEAD).

The strange thing is that this works fine in another project,
so I copied over the simplified mapping file, and the mapping file
and code generation work in the other project.

I've done a bit of digging/fiddling, and I've narrowed it down
to the fact that the new project is using the latest copy
of jakarta-commons-collections, version 3.0, which I gather
is a pretty signifigant change.

I haven't looked at the latest source for 3.0, and I won't have time
till tomorrow (it's quitting time here :).

I guess the big question is whether or not hibernate-tools should
support the use of jakarta-commons-collections 3.0?

Hunter

retnuh · **Joined:** Mon Sep 08, 2003 6:52 am **Posts:** 46

Here's the simplified mapping file I use:

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>

  <class name="com.newbay.mixxe.domain.User" table="users" dynamic-update="true" lazy="true">

    <meta attribute="generated-class">UserVO</meta>
    
    <id name="id" type="int" unsaved-value="0" >
      <generator class="native"/>
    </id>

    <property name="userName" not-null="true" type="string" unique="true"/>
    <property name="password" not-null="true" type="string"/>
  </class>

</hibernate-mapping>

[/code]

max · **Posted:** Tue Mar 23, 2004 6:00 pm

so you are using another library than the one in the distribution ? and especially a library which haven't been released yet ? ;)

so - if i'm going to fix that someone has to tell me what has changed between the two multimap implementations since they don't behave the same ? is it fixable by just casting to List instead of ArrayList ?

retnuh · **Joined:** Mon Sep 08, 2003 6:52 am **Posts:** 46

Well, commons-collections doesn't ship with hibernate tools at all,
and it was officially released two months ago :)

Anyway, I'm gonna try and track down the problem, and see if it is
an easy fix. I'll create a new topic for the follow up.

H