Do something in beginning of methods with injected spring beans and custom annotation

Question

I want to check user permissions in a service-class before each methods execution. this is my current approach:

appContext.xml:

<bean id="requestSeviceImpl" class="services.impl.RequestSeviceImpl">
    <property name="permissionService" ref="permissionServiceImpl" />
    ...
</bean>

implementation:

public class RequestServiceImpl implements RequestService
{
    private PermissionService permissionService;
    ...

    public void setPermissionService(PermissionService permissionService)
    {
        this.permissionService = permissionService;
    }

    @Override
    @Transactional
    public RequestResultModel submitRequest(Request request)
    {
        if(permissionService.isCurrentUserAuthorized(request,"submit"))
        {
            //submit request
        }
        //throw a permission exception
    }

    @Override
    @Transactional
    public void sendRequest(Request request)
    {
        if(permissionService.isCurrentUserAuthorized(request,"send"))
        {
            //send request
        }
        //throw a permission exception
    }

    ...
}

All i want is handling permission checking in my custom annotation (@Secure); It should check permission with permissionService and throws permission exception when its necessary. And i don't want re-instantiate requestServiceImpl or permissionServiceImpl classes (it should use spring beans):

@Override
@Transactional
@Secure(...)
public RequestResultModel submitRequest(Request request)
{
    //submit request
}

How can i do this?

Answer 1

About the only way I can think of is via Aspect Oriented Programming (AOP) . You could use either Spring AOP or AspectJ. You may want to look at the book AspectJ in Action . The first chapter is available as a sample and will explain what you can do with AspectJ. Subsequent chapters use example code that does exactly what you are trying to do, secure a method.