Question

I have a situation where I need to setup a Proxy of a Pooled DataSource, my code is as follows:

<bean id="dataSourceBean" class="com.mchange.v2.c3p0.ComboPooledDataSource" 
    destroy-method="close">
  <property name="driverClass" value="${jdbc.driverClassName}"/>
  <property name="jdbcUrl" value="${jdbc.url}"/>
  <property name="properties">
    <props>
        <prop key="c3p0.minPoolSize">0</prop>
        <prop key="hc3p0.maxPoolSize">100</prop>
        <prop key="hc3p0.timeout">60000</prop>
        <prop key="c3p0.acquire_increment">10</prop>
        <prop key="c3p0.max_statement">50</prop>
        <prop key="user">${jdbc.username}</prop>
        <prop key="password">${jdbc.password}</prop>
    </props>
  </property>
</bean>

<bean id="dataSourceLockAdvice" 
    class="com.ndot2.datasource.DataSourceLockAdvice"/>

<bean id="dataSource" class="org.springframework.aop.framework.ProxyFactoryBean">
    <property name="target" ref="dataSourceBean"/>

    <property name="interceptorNames">
        <list>
            <value>dataSourceLockAdvice</value>
        </list>
    </property>
</bean>

The problem that I’m having is that the connections aren’t being closed anymore and it would seem that the destroy method of the proxied Datasource is no longer being called…

How would I call the Close method of the Proxied Bean? Or should I be implementing the Advice differently?

I’ve tried searching the Internet but I can’t seem to find the answer to this, Help much appreciated!

EDIT:

As requested, here is my transaction management declarations (I’m using Appfuse)

<aop:config>
    <aop:advisor id="userManagerTx" advice-ref="userManagerTxAdvice" pointcut="execution(* *..service.UserManager.*(..))" order="0"/>
    <aop:advisor id="userManagerSecurity" advice-ref="userSecurityAdvice" pointcut="execution(* *..service.UserManager.saveUser(..))" order="1"/>
    <aop:advisor id="managerTx" advice-ref="txAdvice" pointcut="execution(* *..service.*Manager.*(..))" order="2"/>
</aop:config>

<!-- Enable @Transactional support -->
<tx:annotation-driven/>

<!-- Enable @AspectJ support -->
<aop:aspectj-autoproxy/>

<!-- Activates scanning of @Autowired -->
<context:annotation-config/>

<!-- Activates scanning of @Service -->
<context:component-scan base-package="com.ndot2.service"/>

<tx:advice id="txAdvice">
    <tx:attributes>
        <!-- Read-only commented out to make things easier for end-users -->
        <!-- http://issues.appfuse.org/browse/APF-556 -->
        <!--tx:method name="get*" read-only="true"/-->
        <tx:method name="*"/>
    </tx:attributes>
</tx:advice>

<tx:advice id="userManagerTxAdvice">
    <tx:attributes>
        <tx:method name="save*" rollback-for="UserExistsException"/>
    </tx:attributes>
</tx:advice>

<bean id="userSecurityAdvice" class="com.ndot2.service.UserSecurityAdvice"/>

I don’t have any @Transactional or @AspectJ driven Transaction management…

Answer 1

If you have the connection leaks in your application, the first step to do is to try to localize the place where the leaks occur, using the appropriate monitoring tools. As for c3p0, I believe it provides connection monitoring via JMX, as it’s discussed in the related question.

So you can check with the debugging and monitoring tools if the leak occurs during some specific service call.

Then you should watch for different peculiarities: for example, in your configuration UserManager has more than one transaction advice, which could be the cause. In Spring container with annotated configuration a common error is that the bean in not being wrapped by transaction proxy, because the annotated transaction management is configured for the different IoC container. Another possible cause is that your method tries to manage transactions manually, and don’t succeed in doing this correctly.