Mapping problem: not-null property references a null value

austvold · **Posted:** Wed Jun 09, 2004 8:41 am

I am having some trouble solving a problem where Hibernate complaints about "not-null property references a null or transient value" during flush after a delete.

Basically I can not decide wether my model is wrong or if I am using Hibernate incorretly. It surely is not a Hibernate bug :-)

Our product uses Hibernate upon a model of roughly 40 entines which are thightly coupled. We use a variant of the thread-local pattern by allocating a Hibernate session per API-call within a dynamic proxy. JBossCache is our 2nd level cache.

To simplify the scenario for this posting I have put together two entities -- user and authorization. Users can authorize other users.

Mapping file for users:

Code:

<hibernate-mapping>
    <class name="com.foo.PWVUser" table="wvUser" lazy="true">
        <id name="id" type="string" length="32" unsaved-value="null">
            <generator class="uuid.hex"/>
        </id>
         <cache usage="transactional"/>
        <map name="reactiveAuthorizations" inverse="true" cascade="all-delete-orphan" lazy="true"> 
            <cache usage="transactional"/>
            <key column="wvUserId"/>
            <index column="authorizedWVUserId" type="string"/>
            <one-to-many class="com.foo.PReactiveAuthorization"/>
        </map>
    </class>
</hibernate-mapping>

Mapping for authorizations:

Code:

<hibernate-mapping>
    <class name="com.foo.PReactiveAuthorization" table="reactiveAuth" lazy="true">
        <id name="id" type="string" length="32" unsaved-value="null">
            <generator class="uuid.hex"/>
        </id>

         <cache usage="transactional"/>

        <many-to-one name="authorizingWVUser" not-null="true" class="com.foo.PWVUser">
            <meta attribute="field-description">Authorizing user.</meta>
            <column name="wvUserId" index="reactWvUserId"/>
        </many-to-one>

        <many-to-one name="authorizedWVUser" column="authorizedWVUserId" not-null="true" class="com.foo.PWVUser"/>
            <meta attribute="field-description">Authorized user.</meta>
        </many-to-one>
    </class>
</hibernate-mapping>

User class:

Code:

ublic class PWVUser {
    private String id;
    private Map reactiveAuthorizations;

    public PWVUser() {}

    public String getId() {
        return this.id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public Map getReactiveAuthorizations() {
        return this.reactiveAuthorizations;
    }

    public void setReactiveAuthorizations(Map reactiveAuthorizations) {
        this.reactiveAuthorizations = reactiveAuthorizations;
    }
}

Authorization class:

Code:

public class PReactiveAuthorization {
    private String id;
    private PWVUser authorizingWVUser;
    private PWVUser authorizedWVUser;

    public PReactiveAuthorization() {}
    }

    public String getId() {
        return this.id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public PWVUser getAuthorizingWVUser() {
        return this.authorizingWVUser;
    }

    public void setAuthorizingWVUser(PWVUser authorizingWVUser) {
        this.authorizingWVUser = authorizingWVUser;
    }

    public PWVUser getAuthorizedWVUser() {
        return this.authorizedWVUser;
    }

    public void setAuthorizedWVUser(PWVUser authorizedWVUser) {
        this.authorizedWVUser = authorizedWVUser;
    }
}

If a user B wants to authorize a user A, an authorization is created and added to the collection of authorizations on user B.

The problem with not-null field arises when I try to delete the authorized user (user A). Since I do not have a any references of authorizations given upon a user (should I?), I simply do a query to locate all users authorizing the user I am trying to delete, and then update their collection of authorizations:

Code:

 List reactivlyAuthorizingUsers = session.createQuery("select auth.authorizingWVUser from " + PReactiveAuthorization.class.getName() + " auth where auth.authorizedWVUser.id = :wvUserId")
        .setParameter("wvUserId", userA.getId())
        .list();
for (Iterator i = reactivlyAuthorizingUsers.iterator(); i.hasNext();) {
     ((PWVUser) i.next()).getReactiveAuthorizations().remove(userA.getId());
}

When I then do a delete on the userA and flush the session, Hibernate throws a PropertyValueException compliainging about PReactiveAuthorization.authorizedWVUser is null.

I guess that this has something to do with link-owners, but I can not figure out what it is.

Could I use any other relational mapping (ternary?), or should I manage two collections on the user; One for authorizations given to other users and one for authorizations given upon a user. Other suggestions?

System setup:
Hibernate: 2.1.4
Oracle: 9.2.0.1.0
Tomcat: 5.0.19
JVM: Sun 1.4.2_03
Cache: JBoss TreeCache 1.01

Simple test that fails:

Code:

public class LinkOwnerBugOnDeleteTest extends TestCase {
    private net.sf.hibernate.SessionFactory factory;

    public LinkOwnerBugOnDeleteTest(String s) throws Exception {
        super(s);
        SessionFactory.initializeHibernate();
        factory = SessionFactory.getFactory();
    }

    protected void setUp() throws Exception {
        super.setUp();
    }

    protected void tearDown() throws Exception {
        super.tearDown();
    }

    public void testDeleteBug() throws Exception {
        // create user A and B
        PWVUser userA = new PWVUser();
        userA.setUserRef("userA");

        PWVUser userB = new PWVUser();
        userB.setUserRef("userB");
        userB.setReactiveAuthorizations(new HashMap(0));

        Session session;
        Transaction t = null;
        try {
            session = factory.openSession();
            session.setFlushMode(FlushMode.NEVER);
            session.save(userA);
            session.save(userB);
            t = session.beginTransaction();
            session.flush();
            t.commit();
            session.close();
        } finally {
            if (t != null && !t.wasCommitted()) {
                t.rollback();
            }
            t = null;
        }

        Serializable userAId = userA.getId();
        Serializable userBId = userB.getId();

        // add authorization for user A on user B
        try {
            session = factory.openSession();
            session.setFlushMode(FlushMode.NEVER);
            userA = (PWVUser) session.load(PWVUser.class, userAId);
            userB = (PWVUser) session.load(PWVUser.class, userBId);
            PReactiveAuthorization pra = new PReactiveAuthorization();
            pra.setAuthorizedWVUser(userA);
            pra.setAuthorizingWVUser(userB);
            userB.getReactiveAuthorizations().put(userA.getId(), pra);
            t = session.beginTransaction();
            session.flush();
            t.commit();
            session.close();
        } finally {
            if (t != null && !t.wasCommitted()) {
                t.rollback();
            }
            t = null;
        }

        // delete user A
        try {
            session = factory.openSession();
            session.setFlushMode(FlushMode.COMMIT);
            userA = (PWVUser) session.load(PWVUser.class, userAId);
            // delete authorization made upon userA
            List reactivlyAuthorizingUsers = session.createQuery("select auth.authorizingWVUser from " + PReactiveAuthorization.class.getName() + " auth where auth.authorizedWVUser.id = :wvUserId")
                    .setParameter("wvUserId", userA.getId())
                    .list();
            for (Iterator i = reactivlyAuthorizingUsers.iterator(); i.hasNext();) {
                PWVUser otherUser = (PWVUser) i.next();
                Map ras = otherUser.getReactiveAuthorizations();
                ras.remove(userA.getId());
            }
            session.delete(userA);
            t = session.beginTransaction();
            session.flush();
            t.commit();
            session.close();
        } finally {
            if (t != null && !t.wasCommitted()) {
                t.rollback();
            }
            t = null;
        }
    }
}

Thanks for your time :-)

austvold · **Posted:** Thu Jun 10, 2004 6:07 am

Hmm... it seems like I'm quering deaf ears here.

Is my question stupid, not ment for this list or simply to difficult to comment?

perja · **Joined:** Tue Nov 18, 2003 11:56 am **Posts:** 16

Hi, (I guess you found an answer to your problem by now, this is just for other users with a similar problem)

A just had a similar problem and it turned out that earlier in the same (Hibernate) session I've tried to create a domain object where not all required fields were set (doing some junit testing). This resulted in a HibernateException. But I never closed the session in the catch block.

So, the next operation (a delete operation on antoher domain object of the same type but with a different id) I got a exception with the message "not-null property references a null or transient value".

The solution for me was to add a finally block where I close the Hibernate session. Then it worked as expected.

Another idea would be to use the Spring framework to avoid all the try/catch/finally of Hibernate.

intenter · **Joined:** Fri Aug 27, 2004 8:27 am **Posts:** 4

Hi. I have same problem.
Here is my code:

Code:

            Session hsess = sessionFactory.openSession();
            Transaction tx=null;
            try {
                tx = hsess.beginTransaction();
                User user = (User) hsess.load(User.class, userName);
                hsess.delete(user);
                tx.commit();
            } catch (HibernateException he){
                if (tx!=null) tx.rollback();
                throw he;
            } finally {
                hsess.close();
            }

Here is hibernate log output:

Code:

SessionImpl:1158 - deleting a persistent instance
SessionImpl:1178 - deleting [com.exshop.User#fghfgh]
JDBCTransaction:59 - commit
SessionImpl:2242 - flushing session
SessionImpl:2435 - Flushing entities and processing referenced collections
AbstractEntityPersister:274 - com.exshop.Country.code2 is dirty
AbstractEntityPersister:274 - com.exshop.Country.code3 is dirty
SessionImpl:2529 - Updating entity: [com.exshop.Country#178]
JDBCTransaction:82 - rollback

I tried to delete com.exshop.User. I didn't change com.exshop.Country.code2 and code3 propertyes in my application. And i even didn't read their values. They couldn't change (i think). But hibernate detected them "dirty", tried to update Country object and finally exception was throwed: PropertyValueException: not-null property references a null or transient value: com.exshop.Country.code3.
Same exception throws when i try to update User object.

Here are mappings for User and Country objects:

Code:

<hibernate-mapping>

    <class name="com.exshop.User" table="exshop.USERS">

        <id name="name" type="string" unsaved-value="null" >
            <column name="UserName" sql-type="VARCHAR(20)" not-null="true"/>
            <generator class="assigned"/>
        </id>

        <property name="password">
            <column name="Password" sql-type="VARCHAR(15)" not-null="true"/>
        </property>

        <property name="FName">
            <column name="FName" sql-type="VARCHAR(35)" not-null="false"/>
        </property>

        <property name="SName">
            <column name="SName" sql-type="VARCHAR(35)" not-null="false"/>
        </property>

                                     <<skiped>>

        <many-to-one name="country" class="com.exshop.Country" column="COUNTRY_ID" unique="true" cascade="none"/>

        <many-to-one name="region" class="com.exshop.Region" column="REGION_ID" unique="true"/>

        <set name="roles" table="exshop.USERS_ROLES" lazy="false">
            <key column="UserName"/>
            <many-to-many class="com.exshop.Role" column="RoleName"/>
        </set>

        <set name="orders" lazy="false">
            <key column="UserName"/>
            <one-to-many class="com.exshop.Order"/>
        </set>
    </class>

</hibernate-mapping>

Code:

<hibernate-mapping>
    <class name="com.exshop.Country" table="exshop.COUNTRIES">

        <id name="id" type="integer" unsaved-value="0" >
            <column name="ID" sql-type="INTEGER" not-null="true"/>
            <generator class="increment"/>
        </id>

        <property name="name">
            <column name="Name" sql-type="VARCHAR(70)" not-null="true"/>
        </property>

        <property name="code2">
            <column name="Code2" sql-type="VARCHAR(2)" not-null="true"/>
        </property>

        <property name="code3">
            <column name="Code3" sql-type="VARCHAR(3)" not-null="true"/>
        </property>

        <property name="regionName">
            <column name="RegionName" sql-type="VARCHAR(20)" not-null="false"/>
        </property>

        <set name="regions" lazy="true">
            <key column="COUNTRY_ID"/>
            <one-to-many class="com.exshop.Region"/>
        </set>

    </class>

</hibernate-mapping>

I don't know what to think about it. Please, help.

gavin · **Posted:** Fri Aug 27, 2004 8:49 am

Use your debugger. It is probably just a broken get/set pair.

intenter · **Joined:** Fri Aug 27, 2004 8:27 am **Posts:** 4

After i removed properties "code2" and "code3" from mapping file exception disappeared. No other changes were made.

Here is code for Country object:

Code:

public class Country {
    String name;
    String code2;
    String code3;
    String regionName;
    Set regions;
    int id;

    public void setId(int id){
        this.id=id;
    }

    public int getId(){
        return this.id;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name){
        this.name=name;
    }

    public String getCode2() {
        return this.code2;
    }

    public void setCode2(String code2){
        this.code2=code2;
    }

    public String getCode3() {
        return this.code3;
    }

    public void setCode3(String code3){
        this.code2=code3;
    }

    public String getRegionName(){
        return this.regionName;
    }

    public void setRegionName(String regionName){
        this.regionName=regionName;
    }

    public Set getRegions(){
        return this.regions;
    }

    public void setRegions(Set regions){
        this.regions=regions;
    }

    public boolean equals(Object other){
        if (this==other) return true;
        if (other instanceof Country){
            Country another=(Country) other;
            boolean eq=true;
            eq = eq && ((name==another.name) ||(name!=null && name.equals(another.name)));
            eq = eq && ((code2==another.code2) ||(code2!=null && code2.equals(another.code2)));
            eq = eq && ((code3==another.code3) ||(code3!=null && code3.equals(another.code3)));
            eq = eq && ((regionName==another.regionName) ||(regionName!=null && regionName.equals(another.regionName)));
            return eq;
        }
        return false;
    }

    public int hashCode(){
        int hash=7;
        hash=31*hash+(null == name ? 0 : name.hashCode());
        hash=31*hash+(null == code2 ? 0 : code2.hashCode());
        hash=31*hash+(null == code3 ? 0 : code3.hashCode());
        hash=31*hash+(null == regionName ? 0 : regionName.hashCode());
        return hash;
    }
}

intenter · **Joined:** Fri Aug 27, 2004 8:27 am **Posts:** 4

Hi.
It seems i was blind. I found error in previous listing. (in setCode3 method).
So, i have no more questions. Thanks to gavin.