I'm looking for a way to have spring beans registering themselves to a job processor bean who in turn will execute the registered beans on a schedule.
I'm hoping that the bean would just have to implement an interface and by some spring mechanism get registered to the job processor bean. Or alternatively inject the job processor bean into the beans and then somehow the job processor bean can keep track of where it's been injected.
Any suggestions appreciated, it might be that spring is not the tool for this sort of thing?
Use a spring context something like this:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<!--Scans the classpath for annotated
components #Component, #Repository,
#Service, and #Controller -->
<context:component-scan base-package="org.foo.bar"/>
<!--Activates #Required, #Autowired,
#PostConstruct, #PreDestroy
and #Resource-->
<context:annotation-config/>
</beans>
And define a pojo like this:
#Component
public class FooBar {}
And inject like this:
#Component
public class Baz {
#Autowired private FooBar fooBar;
}
Spring has a powerful abstraction layer for Task Execution and Scheduling.
In Spring 3, there are also some annotations that you can use to mark bean methods as scheduled (see Annotation Support for Scheduling and Asynchronous Execution)
You can let a method execute in a fixed interval:
#Scheduled(fixedRate=5000)
public void doSomething() {
// something that should execute periodically
}
Or you can add a CRON-style expression:
#Scheduled(cron="*/5 * * * * MON-FRI")
public void doSomething() {
// something that should execute on weekdays only
}
Here's the XML code you'll need to add (or something similar):
<task:annotation-driven executor="myExecutor" scheduler="myScheduler"/>
<task:executor id="myExecutor" pool-size="5"/>
<task:scheduler id="myScheduler" pool-size="10"/>
Used together with
<context:component-scan base-package="org.foo.bar"/>
<context:annotation-config/>
as described by PaulMcKenzie, that should get you where you want to go.
Related
Hello I'm newbie in Spring AOP.
I have writed something like this:
My Annotation:
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.METHOD)
public #interface ExceptionHandling {
String onSuccess();
String onFailture();
}
Aspect Class:
#Aspect
public class ExceptionHandler implements Serializable {
#Pointcut(value="execution(public * *(..))")
public void anyPublicMethod() {
}
#Around("anyPublicMethod() && #annotation(exceptionHandling)")
public Object displayMessage(ProceedingJoinPoint joinPoint,ExceptionHandling exceptionHandling) throws FileNotFoundException {
try{
Object point = joinPoint.proceed();
new PrintWriter(new File("D:\\log.txt")).append("FUUCK").flush();
FacesMessageProvider.showInfoMessage(
FacesContext.getCurrentInstance(),exceptionHandling.onSuccess());
return point;
} catch(Throwable t) {
new PrintWriter(new File("D:\\log.txt")).append("FUUCK").flush();
FacesMessageProvider.showFatalMessage(
FacesContext.getCurrentInstance(),
exceptionHandling.onFailture());
return null;
}
}
}
Method from ManagedBean
#ExceptionHandling(onSuccess=IMessages.USER_UPDATED,onFailture=IMessages.WRONG_DATA)
public void onClickUpdateFromSession(){
onClickUpdate(sessionManager.getAuthenticatedUserBean());
}
And app-config.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.2.xsd
">
<aop:aspectj-autoproxy/>
<bean id="exceptionHandler"
class="eteacher.modules.ExceptionHandler"/>
<bean id="sessionManager"
class="eteacher.modules.SessionManager"
scope="session"/>
</beans
I'm trying to make exception handler using Spring AOP
and JSF messages but it does not fire the advice.
Please help me.
Spring AOP will only work on Spring managed beans i.e. beans in the ApplicationContext. As your JSF beans aren't managed by Spring but by the JSF container the AOP part isn't going to work.
To make it work either make your JSF managed beans Spring managed beans (see the Spring Reference Documentation for that) or switch to loadtime or compile time weaving of your Aspects.
A note on loadtime weaving is that it might nog work if your JSF classes get loaded before the Spring context is loaded, the newly registered custom classloader cannot modify the bytecode of already loaded classes.
I have the code #Inject works in one class but not in other.
Here's my code:
context.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation=" http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
">
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver"></bean>
<context:component-scan base-package="com.myfashions.services"/>
<context:component-scan base-package="com.myfashions.dao"/>
</beans>
SellerRetriever.java
public class SellerRetriever {
#Inject
UserDAO userDAO;
...
...
}
UserDAO class is present in com.myfashions.dao package.
#Inject is not working in Seller.java. Any reason why?
Make sure that both SellerRetriever and the implementation of UserDAO are annotated for the component scan. This will ensure that the latter is injected into the former:
#Service
public class SellerRetriever {
#Inject
UserDAO userDAO;
...
}
Annotate the UserDAO implementation with #Component.
When scanning multiple paths use:
<context:component-scan base-package="com.myfashions.services, com.myfashions.dao"/>
To be eligible to scan, your class must be annotated with either a more generic #Component, or #Service or #Repositories etc.. In your case, #Service logically better fits.
You could then (if you need) define some aspects (AOP) focused specifically on services call.
Besides, you may want to use #Autowired instead of #Inject to retrieve your bean.
For more information about differences concerning these two annotations:
What is the difference between #Inject and #Autowired in Spring Framework? Which one to use under what condition?
and you can see my comment just below explaining one good reason to keep #Autowired instead of #Inject.
I found my mistake, I'm posting this because in case anyone has the same problem. I used new operator to create an SellerRetriver object. Inject won't work if new operator is used to call that particular class.
I'm trying to test a simple Aspect.
The app compiles and runs fine, BUT I do not get the Aspect executed. Or at least, I do not get the output the aspect should produce.
(my aim is to write an exception logger for any ex that occures in the app. but first this test aspect should run...)
Maybe someone who has more experience in aspects see's what I'm doing wrong?
package business;
public interface Customer {
void addCustomer();
}
import org.springframework.stereotype.Component;
#Component
public class CustomerImpl implements Customer {
public void addCustomer() {
System.out.println("addCustomer() is running ");
}
}
#RequestScoped #Named
//this is backing bean for jsf page
public class Service {
#Inject
Customer cust;
add() {
System.out.println("Service is running ");
cust.addCustomer();
}
}
#Aspect
public class AspectComp {
#Before("within(business..*)")
public void out() {
System.out.println("system out works!!");
}
}
Spring:
<beans
xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:beans="http://www.springframework.org/schema/beans"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
">
<context:annotation-config />
<context:component-scan base-package="business" />
<aop:aspectj-autoproxy />
</beans>
Output:
Service is running
addCustomer() is running
The Aspect statement is missing.
You are creating your Component with its constructor, and not getting it from Spring container! That's the problem, or you must use AspectJ's load-time weaver.
Just inject your component (CustomerImpl) in your service and then use the injected instance.
I remember having a similar problem once; Spring wasn't actually loading the proxy as it did not recognize the #Aspect annotation as being an annotation-scanable bean. I added the #Component annotation to the #Aspect notation and Spring started scanning it.
I never looked into the reasons why this happened, and why I needed to do that, so I cannot confirm that is the "proper" way of doing things. My gut would tell me that I had something missing in my config file; I can't imagine why Spring would not scan for #Aspect beans.
The other thing you can do, is to explicitly declare your Aspect bean in the XML config file as well to see if this the same type of problem you're having.
You can also enable debug logging in the Spring framework and see if your bean is being loaded by Spring. If not, then it gives you an idea where to start looking.
I have a ServiceA which has a dependency on ServiceB. The serviceB comes from a spring bean file with lazy-init=true i.e, I only want serviceB to be initialised when and if I ask for that bean.
However I do use ServiceA throughout my application and when we do a setter based injection ServiceB gets initialised.
I want ServiceA to not initialise ServiceB until any method in ServiceA is called that needs ServiceB. One way of doing this was using the Aspects but I was looking at the simplest possible solution for this particularly in the Spring XML file for serviceB or some annotation in serviceB or any proxy flag.
I think LazyInitTargetSource does what you need.
Useful when a proxy reference is needed on initialization but the actual target object should not be initialized until first use. When the target bean is defined in an ApplicationContext (or a BeanFactory that is eagerly pre-instantiating singleton beans) it must be marked as "lazy-init" too, else it will be instantiated by said ApplicationContext (or BeanFactory) on startup.
Another approach that you might want to try is discussed at http://static.springsource.org/spring/docs/3.1.x/javadoc-api/org/springframework/aop/framework/autoproxy/target/LazyInitTargetSourceCreator.html:
[LazyInitTargetSourceCreator is a] TargetSourceCreator that enforces a LazyInitTargetSource for each bean
that is defined as "lazy-init". This will lead to a proxy created for
each of those beans, allowing to fetch a reference to such a bean
without actually initialized the target bean instance.
To be registered as custom TargetSourceCreator for an auto-proxy
creator, in combination with custom interceptors for specific beans or
for the creation of lazy-init proxies only. For example, as
autodetected infrastructure bean in an XML application context
definition:
<bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
<property name="customTargetSourceCreators">
<list>
<bean class="org.springframework.aop.framework.autoproxy.target.LazyInitTargetSourceCreator"/>
</list>
</property>
</bean>
<bean id="myLazyInitBean" class="mypackage.MyBeanClass" lazy-init="true">
...
</bean>
If you find yourself doing this several times in an application context, this will save on configuration.
I don't know about Spring, but in Guice you would use a Provider<ServiceB>, so that when you were ready to use the service you'd go provider.get().callMethodOnB(...).
This is, I believe, part of the JSR-330 spec, so it's possible there's an equivalent thing in Spring (I haven't used an up-to-date version of Spring for quite some time).
You can also use method injection.
As a rule it's required to obtain a new instance of a singleton bean from a context, but it can be used in your case too.
Sample:
package org.test.lazy;
public abstract class ParentBean {
public abstract LazyBean getLazy();
public void lazyDoingSomething() {
getLazy().doSomething();
}
}
package org.test.lazy;
public class LazyBean {
public void init() {
System.out.println("Initialized");
}
public void doSomething() {
System.out.println("Doing something");
}
}
package org.test.lazy;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
#ContextConfiguration
#RunWith(SpringJUnit4ClassRunner.class)
public class LazyTest {
#Autowired
private ParentBean parentBean;
#Test
public void test() {
parentBean.lazyDoingSomething();
parentBean.lazyDoingSomething();
}
}
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
">
<import resource="classpath:org/test/lazy/Lazy-context.xml"/>
<bean id="parentBean" class="org.test.lazy.ParentBean">
<lookup-method bean="lazyBean" name="getLazy"/>
</bean>
</beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
"
default-lazy-init="true">
<bean id="lazyBean" class="org.test.lazy.LazyBean" init-method="init" />
</beans>
So you lazy bean will be initialized only once on demand.
I have next situation:
Connection manager should have each time one object of ConnectionServer and new objects of DataBean
So, I have created these beans and configured out it spring xml.
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<bean id="dataBena" class="com.test.DataBean" scope="prototype"/>
<bean id="servCon" class="com.test.ServerCon"/>
<!--<bean id="test" class="com.test.Test"/>-->
<context:component-scan base-package="com.test"/>
</beans>
and added scope prototype for DataBean
After this I've created simple util/component class called Test
#Component
public class Test {
#Autowired
private DataBean bean;
#Autowired
private ServerCon server;
public DataBean getBean() {
return bean.clone();
}
public ServerCon getServer() {
return server;
}
}
BUT, Each time of calling getBean() method I am cloning this bean, and this is the problem to me.
Can I do it from spring configuration without usning clone method?
Thanks.
You are looking for lookup method functionality in Spring. The idea is that you provide an abstract method like this:
#Component
public abstract class Test {
public abstract DataBean getBean();
}
And tell Spring that it should implement it at runtime:
<bean id="test" class="com.test.Test">
<lookup-method name="getBean" bean="dataBean"/>
</bean>
Now every time you call Test.getBean you will actually call Spring-generated method. This method will ask ApplicationContext for DataBean instance. If this bean is prototype-scoped, you will get new instance each time you call it.
I wrote about this feature here.