[FIXED] How do you intercept a bean reference?

Issue

My Spring configuration looks like

    ...
    <bean id="myWriter" class="org.springframework.batch.item.database.JdbcBatchItemWriter">
        ...
        <property name="sql" value="%[insert.sql.command]" />
 ==>    <property name="dataSource" ref="outDataSource1" />
    </bean>

    <bean id="myWriter" class="org.springframework.batch.item.database.JdbcBatchItemWriter">
        ...
        <property name="sql" value="%[insert.sql.command]" />
 ==>    <property name="dataSource" ref="outDataSource2" />
    </bean>
    ...
    <bean id="outDataSource1" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="%[outds1.driverClassName]" />
        <property name="url" value="%[outds1.url]" />
        <property name="username" value="%[outds1.username]" />
        <property name="password" value="%[outds1.password]" />
    </bean>

    <bean id="outDataSource2" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="%[outds2.driverClassName]" />
        <property name="url" value="%[outds2.url]" />
        <property name="username" value="%[outds2.username]" />
        <property name="password" value="%[outds2.password]" />
    </bean>
    ...

I would like to display information for the DataSource referenced in each writer (JdbcBatchItemWriter class). DataSource is implemented by a Spring DriverManagerDataSource.

For example, display infos :

(DriverManagerDataSource).getUrl()
(DriverManagerDataSource).getUsername()

So I wrapped JdbcBatchItemWriter in a, say JdbcBatchItemWriterWrapper, based on an ApplicationContextAware.

Since JdbcBatchItemWriter DOES NOT HAVE any getDataSource() getter, I need to resolve/instantiate the ref of the property dataSource programatically. How can I do this?

Solution

The only place you could intercept the DataSource is before the setDataSource call implied by the

<property name="dataSource" ref="outDataSource2" />

One solution is to extend the JdbcBatchItemWriter and override its setDataSource, log the value that is passed to it, then delegate to the super implementation.

Instead of providing JdbcBatchItemWriter as the bean class, you provide your subclass.

Answered By - Sotirios Delimanolis
Answer Checked By - Willingham (JavaFixing Volunteer)