File resource changes not visible in TimerTask run ()

[adi7]

Hi,

I am passing text file as classpath resource to TimerTask bean and reading in run() method as follows -

<property name="resource" value="classpath:somemap.txt"/>

public void run () {

BufferedReader reader = new BufferedReader(new InputStreamReader(resource.getInputStream()));

}

But the problem is if i change somemap.txt contents at runtime, changes are not picked up in next run of the timer task

any ideas ?

thanks
adi

[Hetal B]

Can you please post some more snippet if possible(bean definition to be specific)

[adi7]

actually i managed to get updates by using

BufferedReader reader = new BufferedReader(new FileReader(resource.getFile()));

instead of
BufferedReader reader = new BufferedReader(new InputStreamReader(resource.getInputStream()));

[adi7]

bean definitions as follows

<bean id="fileReaderTask" class="com.db.gme.analytics.eas.aws.util.RepeatTas k">
<property name="resource" value="classpath:somemap.txt"/>
</bean>

<bean id="scheduledTask" class="org.springframework.scheduling.timer.Schedu ledTimerTask">
<property name="delay" value="0" />
<!-- run every 15 minutes -->
<property name="period" value="900000" />
<property name="timerTask" ref="repeatTask" />
</bean>

<bean id="timerFactory" class="org.springframework.scheduling.timer.TimerF actoryBean">
<property name="scheduledTimerTasks">
<list>
<ref bean="scheduledTask" />
</list>
</property>
</bean>

[denis.zhdanov]

It looks like the class loader used at your application performs resources caching. That may be the case for Tomcat class loader for example (afair it caches last 500 requested resources by default).

The general idea of your solution is correct - use the approach that avoids class loader-level caching. However, it can be implemented more elegantly by automatically replacing injected 'org.springframework.core.io.ClassPathResource' object by implied 'org.springframework.core.io.FileSystemResource' object. You can use the following algorithm:

1. Write the code that has a chance to intercept new resource injection (e.g. by loading resources via custom ResourceLoader or applying aspectj weaving-based AOP);
2. Check if Resource.isReadable() returns 'true' and Resource.getFile() doesn't throw an exception;
3. Create new Resource implementation that wraps given resource and delegates all calls except getInputStream() to it. 'getInputStream()' should be implemented via FileInputStream;
   [I]Inject the object constructed above as a dependency to the target bean instead of initial resource;

Such an approach allows to solve the problem transparently to all defined beans.