Spring and Hibernate’s getCurrentSession()

If you are using Spring to wrap a Hibernate SessionFactory and you are not using Spring-managed transactions, you may run into an issue. The reason is that Spring by default will wrap Hibernate’s SessionFactory implementation and delegate to its own transactional version. If you are just using the simple ThreadLocal-based session-per-request functionality, then when you attempt to open the Session, you will get an IllegalStateException thrown, with the error message "No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here". This happens because Spring’s SessionFactoryUtils checks if the Session is bound to Spring’s transactional support, and by default throws an error if it is not.

The solution to this is to set the property

<property name="exposeTransactionAwareSessionFactory"><value>false</value></property>

in the Spring config. This will return the “raw” SessionFactory instead of the proxied one. A snippet of code from AbstractSessionFactoryBean shows where the check is done:

 
/**
   * Wrap the given SessionFactory with a transaction-aware proxy, if demanded.
   @param rawSf the raw SessionFactory as built by <code>buildSessionFactory()</code>
   @return the SessionFactory reference to expose
   @see #buildSessionFactory()
   @see #getTransactionAwareSessionFactoryProxy
   */
  protected SessionFactory wrapSessionFactoryIfNecessary(SessionFactory rawSf) {
    if (isExposeTransactionAwareSessionFactory()) {
       return getTransactionAwareSessionFactoryProxy(rawSf);
    }
    else {
      return rawSf;
    }
  }

A sample Spring config is shown below.

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
       http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd">

  <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName" value="org.hsqldb.jdbcDriver"/>
    <property name="url" value="jdbc:hsqldb:hsql://localhost:9001"/>
    <property name="username" value="sa"/>
    <property name="password" value=""/>
  </bean>

  <bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
    <property name="dataSource" ref="dataSource"/>
     <property name="exposeTransactionAwareSessionFactory"><value>false</value></property>
    <property name="annotatedPackages">
      <list>
        <value>uk.co.researchkitchen.hibernate</value>
      </list>
    </property>
    <property name="annotatedClasses">
        <list>
                <value>uk.co.researchkitchen.hibernate.Product</value>
                <value>uk.co.researchkitchen.hibernate.ProductDescription</value>
        </list>
    </property>
    <property name="hibernateProperties">
      <value>
        hibernate.dialect=org.hibernate.dialect.HSQLDialect
        hibernate.show_sql=true
            hibernate.hbm2ddl.auto=create
            hibernate.current_session_context_class=thread
      </value>
    </property>
  </bean>

</beans>

Ignoring Bash Aliases

If you have any aliases defined in your .bashrc or .bash_profile files, occassionally you may run into a situation where you would like to selectively ignore those aliases. In my shell, I have aliased ls like so:

alias ls ‘ls -lF –color’

However, when running a simple command like the following (which searches for filenames within a set of jar files), this breaks, as the output of ls is in long format. Instead of having to use cut or awk to slice off the parts of the output we need, we can escape the aliased command, effectively telling bash to ignore the alias:

for j in $(\ls *.jar); do jar tvf $j | grep -i “gfxjavactask” ; done

Note the \ in front of the command name. This is an obscure one, I know! :-)