Hello,

I have been struggling for quite some time with this problem. I have a parent child relationship that I want to save to the database. When I call session.saveOrUpdate(myParent); The program hangs forever. This relationship works fine for reading data already saved in the database, or saving the parent when the child collection is empty. Here is my java code:


Session session = null;
try
{
session = database.getSessionFactory().openSession();
Transaction transaction = session.beginTransaction();
System.out.println("BEFORE SAVE");
session.saveOrUpdate(filter);
System.out.println("SAVED");
session.delete(filter);
System.out.println("DELETED");
transaction.commit();
}
catch(HibernateException e)
{
e.printStackTrace();
}
finally
{
System.out.println("FINALLY");
try
{
session.close();
}
catch(HibernateException e)
{
e.printStackTrace();
}
}

Here is the mapping file:

<?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.atwoodsoft.data.Language" table="Language">
<id name="id" type="int" column="id" unsaved-value="-1" >
<generator class="assigned"/>
</id>
<property name="name" column="name" type="string" length="50" not-null="true"/>
<property name="localName" column="localName" type="string" length="50" not-null="true"/>
<property name="languageCode" column="languageCode" type="string" length="50" not-null="true"/>
</class>
<class name="com.atwoodsoft.tools.translator.LanguageFilter" table="LanguageFilter">
<id name="id" type="int" column="id" unsaved-value="-1" >
<generator class="native"/>
</id>
<property name="nullFilterMode" column="nullFilterMode" type="int" not-null="true"/>
<property name="index" column="index" type="int" not-null="true"/>
<property name="filterExpression" column="filterExpression" type="string" not-null="false"/>
<many-to-one name="language" class="com.atwoodsoft.data.Language" column="language"/>
<many-to-one name="filter" class="com.atwoodsoft.tools.translator.TranslatorFilter" column="filter" not-null="true"/>
</class>
<class name="com.atwoodsoft.tools.translator.TranslatorFilter" table="TranslatorFilter">
<id name="id" type="int" column="id" unsaved-value="-1" >
<generator class="native"/>
</id>
<property name="name" column="name" type="string" not-null="true" length="50" />
<property name="description" column="description" type="string" not-null="false" length="100"/>
<list name="selectedLanguageFilters" cascade="all" inverse="true">
<key column="filter"/>
<index column="index"/>
<one-to-many class="com.atwoodsoft.tools.translator.LanguageFilter"/>
</list>
<!--bag name="selectedLanguageFilters" cascade="all" inverse="true">
<key column="filter"/>
<one-to-many class="com.atwoodsoft.tools.translator.LanguageFilter"/>
</bag-->
</class>
</hibernate-mapping>


And here is the relavent portion of the hibernate log:

BEFORE SAVE
22:57:57,675 DEBUG Cascades:190 - unsaved-value: -1
22:57:57,677 DEBUG SessionImpl:1213 - saveOrUpdate() unsaved instance with id: -1
22:57:57,679 DEBUG SessionImpl:671 - saving [com.atwoodsoft.tools.translator.TranslatorFilter#<null>]
22:57:57,681 DEBUG Cascades:301 - processing cascades for: com.atwoodsoft.tools.translator.TranslatorFilter
22:57:57,684 DEBUG Cascades:308 - done processing cascades for: com.atwoodsoft.tools.translator.TranslatorFilter
22:57:57,738 DEBUG SessionImpl:2506 - Wrapped collection in role: com.atwoodsoft.tools.translator.TranslatorFilter.selectedLanguageFilters


Any suggestions or advice would be greatly appreciated.

John Atwood

No idea. How about you run it in the debugger and pause the program during the hang; see what it is waiting for.

When running the debugger this is what I found:

/**Adds a new <code>LanguageFilter</code> to this <code>TranslatorFilter</code>. If a <code>LanguageFilter</code>
* is already registered with the same language then it is overritten in favor of the new <code>LanguageFilter</code>*/
public void addLanguageFilter(LanguageFilter filter)
{
if(getLanguageFilter(filter.getLanguage()) != null) //if we already have a LanguageFilter for the specified language
{
int index = selectedLanguageFilters.indexOf(getLanguageFilter(filter.getLanguage()));
selectedLanguageFilters.add(index,filter); //GAVIN This is where the program stops
filter.setIndex(index);
}
else
{
selectedLanguageFilters.add(filter);
reOrder();
}
filter.setFilter(this);
}

Here is the stack trace.

addLanguageFilter():171, com.atwoodsoft.tools.translator.TranslatorFilter
setSelectedLanguageFilters():103, com.atwoodsoft.tools.translator.TranslatorFilter
setPropertyValues(), com.atwoodsoft.tools.translator.TranslatorFilterMetaClass0
setPropertyValues():158, net.sf.hibernate.persister.AbstractEntityPersister
doSave():724, net.sf.hibernate.impl.SessionImpl
save():620, net.sf.hibernate.impl.SessionImpl
saveOrUpdate():1214, net.sf.hibernate.impl.SessionImpl

From this stack trace I am guesing that Hibernate saves my data succesfully to the database and then, within the same transaction, tries to reload the object being saved. The problem seems to be caused when hibernate tries to set the languageFilter's property. This is probably because the setSelectedLanguageFilters method implements logic to ensure that the order of LanguageFilters in the list is corrospondent to their index property. I am wondering why does hibernate try to repopulate an object that has just been saved?

Thanks,

John

Hibernate is allowed to call your getters/setters at ANY time. For example, it might like to wrap a collection. Or, it might want to increment a version number. Or, you might have an Interceptor defined.


You should implement get/set pairs so that it is impossible to cause an infinite loop. By the look of the code, you have some dodgy recursion going on.

Thanks Gavin,

Adding the line:

public void setSelectedLanguageFilters(List languageFilters)
{
if(!langaugeFilters.equals(selectedLanguageFilters))
{
//do collection processing work here
}
...
}

seems to have made things work. I will continue to work on it and perhaps switch to a more simple list mapping.

Thanks,
John