[Springframework-developer] Creating valid objects at construction time

[Bill S. <bi...@gm...>]

Spring developers,

First off, thank you very much for a wonderful framework.

I am in the process of writing a short paper on the Spring Framework in
which I exclusively use Spring programmatically.  During this process, I've
found quite a few implementations of the InitializingBean interface that
have empty constructors, forcing me to call a few setter() methods, and
finally call an afterPropertiesSet() method to fully construct it.  (I do
understand that when using an XML-based application context, the Spring
container calls the setters and afterPropertiesSet() for you.  I want to use
Spring programmatically).


For example, in my Service Locator, I instantiate a LocalSessionFactoryBean
as follows:

    private void initializeSessionFactory() throws Exception {
        _localSessionFactoryBean = new LocalSessionFactoryBean();
        Properties hibernateProperties = new Properties();
        hibernateProperties.setProperty("hibernate.dialect","
org.hibernate.dialect.PostgreSQLDialect");
        _localSessionFactoryBean.setDataSource(_dataSource);
        _localSessionFactoryBean.setMappingResources(new
String[]{"com/billsix/examples/atm/DomainObjects.hbm.xml"});

_localSessionFactoryBean.setHibernateProperties(hibernateProperties);
        _localSessionFactoryBean.afterPropertiesSet();
    }


I prefer to create valid objects at construction time, so I would like the
following constructor.

     public LocalSessionFactoryBean(DataSource dataSource, Properties
hibernateProperties, String[] mappingResources)
     {
       setDataSource(dataSource);
       setHibernateProperties(hibernateProperties);
       setMappingResources(mappingResources);
        afterPropertiesSet();
     }


This would allow me to instantiate a LocalSessionFactoryBean as follows:

    private void initializeSessionFactory() throws Exception {
        Properties hibernateProperties = new Properties();
        hibernateProperties.setProperty("hibernate.dialect","
org.hibernate.dialect.PostgreSQLDialect ");
        _localSessionFactoryBean = new
LocalSessionFactoryBean(_dataSource,hibernateProperties,new
String[]{"com/billsix/examples/atm/DomainObjects.hbm.xml"} );
    }



I have found that some Spring classes offer both empty constructors as well
as constructors in the style I described above, such as the hibernate3
HibernateTransactionManager and the TransactionInterceptor.  (Although,
TransactionInterceptor's constructors currently don't have calls
afterPropertiesSet() in the last line of each.)



If I create patches for InitializingBeans in which I'd like a constructor
with arguments, will they be accepted?  If not, why not?

I've never contributed to an open source project before - I assume all I
have to do is to create "improvement" issues in JIRA, submitting patches for
each InitializingBean.  Is that correct?

Thanks again,
Bill Six