Accessing the hibernateSessionFactory bean

[Marten Deinum]

The first one wont work. I am using Spring 2.0 and I need 2.0.1 for that. And it is out of my controll as I get my libraries from Maven and I do not update it.

You could always try and request an update to 2.0.1 or greater. However the second option would work for you.

[mpetrashev]

getHibernateProperties() does not give me any information about the dataSource it was instansiated with, only some properties like hibernate.dialect etc.

What do you mean under dataSource? You can call getDataSource() method or repeat the same magic with "&dataSource" bean. But anyway, can you clarify what do you mean under:

How could I check the session factory bean to check which datasource it uses?

Bean instance? Url? JNDI name? DataSource property has abstract type (interface) ...

[DJViking]

Is Spring 2.0 really the last Maven-distributed release?? Anyway that's really a reason not to upgrade? Very questionable policy IMO.

The other solution of manipulating LocalSessionFactoryBean is even worse. You should not change properties of a singleton bean in general! The same applies to the DataSource IMO.

The best is probable to copy the code for AbstractRoutingDataSource (or the concrete implementation that meets your needs) if you really can't upgrade Spring.

Jörg

Well as it is the repository I use is on an internal server which I do not maintain. I could probally issue a request for the person in charge to download and make avaiable the latest Spring release.

[DJViking]

What do you mean under dataSource? You can call getDataSource() method or repeat the same magic with "&dataSource" bean. But anyway, can you clarify what do you mean under:



Bean instance? Url? JNDI name? DataSource property has abstract type (interface) ...

I do read the datasource bean in my current code from the application context, but I want to know if the session factory uses the new updated datasource or the old that was instansiated with it when the application context was set.

The application context gets its properties for the datasource bean from a properties file. In this properties file I have 8 URL for different databases, but same table structure. When the user choose a new datasource I update the datasource bean I retrieve from the application context.

When I look up in the database does the session factory look up in the datasource object from the application context or does it have a local copy of it which was instansiated when the application context created its bean objects ??

[Jörg Heinicke]

When I look up in the database does the session factory look up in the datasource object from the application context or does it have a local copy of it which was instansiated when the application context created its bean objects ??

It should have a reference, not a copy. So it should have the updated values. BUT you get into concurrency issues with this approach. What happens when a connection is tried to open while you are reconfiguring the datasource? I wonder how you want to preclude this. And even if for any reason the concurrent access can't happen you add a invisible global state to your application. What happens if a database access fails and you have to find out why? Which datasource configuration was actually in use? And so on ... Just don't do this ...

Jörg

[DJViking]

And so on ... Just don't do this ...

Jörg

Well, Somehow I have to do this. One way or the other. Perhaps I can switch to use the AbstractRoutingDataSource

[DJViking]

I just found out that after makeing a change to the datasource the session factory did not use the new datasource, but the default one set up in the application context. It did not matter if I changed the datasource bean.

if(!applicationContextIsSet)
setApplicationContext();
 
BasicDataSource dataSource = (BasicDataSource) applicationContext.getBean("dataSource");
if(!dataSource.getUrl().equals(URL))
dataSource.setUrl(URL);
 
private void setApplicationContext(){
applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
applicationContextIsSet = true;
}

Then later in the code I access the methods that perform the database operations

This is how I have arranged the context file:

 
    <bean id="hibernateSessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"
        init-method="afterPropertiesSet">
 
        <property name="mappingResources" ref="mappingResources"/>
        <property name="hibernateProperties" ref="hibernateProperties"/>
        <property name="dataSource" ref="dataSource"/>
     </bean>
 
   <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="maxActive" value="0"/><!-- 0 means unlimited num of connections -->
        <property name="driverClassName" value="${datasource.driverClassName}"/>
        <property name="url" value="${datasource.url}"/>
        <property name="username" value="${datasource.username}"/>
        <property name="password" value="${datasource.password}"/>
    </bean>
 
    <bean id="someService" class="some.service.SomeServiceImpl">   
      <property name="hibernateTemplate" ref="hibernateTemplate"/>   
    </bean>   
 
    <!-- HibernateTemplate -->
    <bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate">
        <property name="sessionFactory" ref="hibernateSessionFactory"/>
    </bean>

When I access the "someService" and it gets its data with hibernate, first through hibernateTemplate then hibernateSessionFactory which access the dataSource.
But it does not seems like changeing the DataSource URL helps(I change it before I call getBean("someService") ).

[DJViking]

It should have a reference, not a copy. So it should have the updated values.
Jörg

How can that be? I have tried numerous way of changeing the URL of the data source object in the application context, but the session factory does not use a data source with the new URL. It seems like it uses the data source which was created when the application context was set.

[Jörg Heinicke]

It seems like it uses the data source which was created when the application context was set.

There are not two datasources - at least as far as Spring knows. You change the url property of THE datasource directly, so it is automcatically available in the LocalSessionFactoryBean as well.

BUT there is a reason why it does not work the way you are doing it at the moment. (Did I mention you should not do it this way? Couldn't resist ... ) I had a look into the source of BasicDataSource. It's actually only a wrapper around the "real" datasource. Only setting the url does not change anything in it. It does not write through the actual datasource, but only sets the url property of BasicDataSource itself and restartNeeded to true. The latter one is never asked for. And createDataSource only creates a new instance if there is none. So always the same datasource is used. There is also following Javadoc comment in it:

 * Returns whether or not a restart is needed. 
 * Note: restart is not currently triggered by property changes.

It also has an unused method restart() which is private unfortunately. But it only executes the one and only solution at the moment anyway: To reset the internal datasource to null so that it is not reused on next access to getConnection() is to call close() on BasicDataSource.

Jörg