[S2] Equivalent of Servlet init() method?
Hi I'm a struts2 newbie I've just got the hello world app running. I'm now trying to convert a simple servlet app to struts2. In the original servlet I use a singleton factory class which I initialise/setup in the servlets init() method and use it in the servlet service() method. What is the equivalent means of achieving this on Struts2 so that I can set up the factory once and simply use it in my action class. In addition, other than the wiki I'd be grateful if anyone could recommend other documentation/tutorial sources. Should I also be reading up on WebWork /or Struts 1? Regards Roger - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: [S2] Equivalent of Servlet init() method?
I looked for something similar a while back and didn't find anything simple. There are servlet context listeners (but that isn't really struts-2-ish). What I did (and I know it's inelegant) is to create a static initializer block. One main difference to remember between servlets and actions is that servlets are initialized once and remain in memory. Actions seem to be on a one-per-request lifecycle. So, if you have a factory that you want to use, it has to be either static in your action, or static in another class. -Wes -Original Message- From: Roger Varley [mailto:[EMAIL PROTECTED] Sent: Thursday, February 22, 2007 9:10 AM To: user@struts.apache.org Subject: [S2] Equivalent of Servlet init() method? Hi I'm a struts2 newbie I've just got the hello world app running. I'm now trying to convert a simple servlet app to struts2. In the original servlet I use a singleton factory class which I initialise/setup in the servlets init() method and use it in the servlet service() method. What is the equivalent means of achieving this on Struts2 so that I can set up the factory once and simply use it in my action class. In addition, other than the wiki I'd be grateful if anyone could recommend other documentation/tutorial sources. Should I also be reading up on WebWork /or Struts 1? Regards Roger - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] smime.p7s Description: S/MIME cryptographic signature
RE: [S2] Equivalent of Servlet init() method?
I could be wrong, but perhaps you should use the Spring IoC container for this. I can't point you to the correct documentation off hand, but I believe that this is the way to maintain a resource such as what you had previoulsy done with the Servlet's init method and the factory class. Maybe someone with more experience integrating spring and struts2 can chime in with some doc recommendations. I'm a bit of a newbie myself unfortunatley. ___ Join Excite! - http://www.excite.com The most personalized portal on the Web! - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: [S2] Equivalent of Servlet init() method?
On 2/22/07, Wesley Wannemacher [EMAIL PROTECTED] wrote: I looked for something similar a while back and didn't find anything simple. There are servlet context listeners (but that isn't really struts-2-ish). I would strongly disagree that ServletContextListeners are not really struts-2-ish. They are probably the best way to do any one-time initialization for an application, unless there's already some other code to do what you need... On 2/22/07, bob [EMAIL PROTECTED] wrote: I could be wrong, but perhaps you should use the Spring IoC container for this. I can't point you to the correct documentation off hand, but I believe that this is the way to maintain a resource such as what you had previoulsy done with the Servlet's init method and the factory class. Maybe someone with more experience integrating spring and struts2 can chime in with some doc recommendations. I'm a bit of a newbie myself unfortunatley. I don't think you have to use the Spring IoC container for this, but I think it's probably a pretty good way to do it. I am extremely fond of using Spring to establish an application context (not to be confused with the webapp application context) and letting most of my code be blissfully ignorant of how things get set up. This page is the place to start on using the Spring plugin with Struts 2: http://struts.apache.org/2.x/docs/spring-plugin.html In short, Spring can instantiate any beans you want, either as singletons or as prototypes (that is, a new bean is instantiated each time it is called for from the Spring app context). In instantiating, it can also satisfy dependencies automagically. In the Struts2/Spring model, this is usually applied to action classes, which would be instantiated by Spring when requested by Struts. Spring would just give you an Action instance with a reference to your factory (although once you start digging in Spring, you might find that you can even hide the Factory and keep your Actions super simple and flexible.) Joe -- Joe Germuska [EMAIL PROTECTED] * http://blog.germuska.com The truth is that we learned from João forever to be out of tune. -- Caetano Veloso
Re: [S2] Equivalent of Servlet init() method?
I see a couple of options. The first would be to create an interceptor for your singleton factory. In the init of the interceptor you would initialize this factory and then provide some mechanism to inject that factory into your actions. (possibly via a FactoryAware interface) Another option would be to convert your factory to use spring. Spring provides mechanisms to initialize beans: http://static.springframework.org/spring/docs/2.0.x/reference/beans.html#beans-factory-lifecycle-initializingbean Tom bob wrote: I could be wrong, but perhaps you should use the Spring IoC container for this. I can't point you to the correct documentation off hand, but I believe that this is the way to maintain a resource such as what you had previoulsy done with the Servlet's init method and the factory class. Maybe someone with more experience integrating spring and struts2 can chime in with some doc recommendations. I'm a bit of a newbie myself unfortunatley. ___ Join Excite! - http://www.excite.com The most personalized portal on the Web! - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: [S2] Equivalent of Servlet init() method?
On 2/22/07, Joe Germuska [EMAIL PROTECTED] wrote: This page is the place to start on using the Spring plugin with Struts 2: http://struts.apache.org/2.x/docs/spring-plugin.html In short, Spring can instantiate any beans you want, either as singletons or as prototypes (that is, a new bean is instantiated each time it is called for from the Spring app context). In instantiating, it can also satisfy dependencies automagically. In the Struts2/Spring model, this is usually applied to action classes, which would be instantiated by Spring when requested by Struts. Spring would just give you an Action instance with a reference to your factory (although once you start digging in Spring, you might find that you can even hide the Factory and keep your Actions super simple and flexible.) Oh, yes, I just remembered -- the page above has a Spring config file example using the Spring 1.x DTD. If you should instead use the Spring 2.xDTD (which you could, because Struts depends upon Spring 2), you must be aware that the default instantiation model for Spring 2 is singleton, not prototype, and that is at odds with the model behind WebWork, which assumes that each action is instantiated once per request. Thus, the example which is in the page referenced above: bean id=bar class=com.my.BarClass singleton=false/ would become bean id=bar class=com.my.BarClass scope=prototype/ Took me a little bit to realize that that was the source of a few quirks when I was first setting out with Struts2/Spring2. -- Joe Germuska [EMAIL PROTECTED] * http://blog.germuska.com The truth is that we learned from João forever to be out of tune. -- Caetano Veloso
RE: [S2] Equivalent of Servlet init() method?
I guess you're right, it's not that they aren't struts-2-ish... But, one significant advantage of a static initializer block vs. servlet context listeners is easier unit testing. I found it much easier to write the unit tests for my actions if the JVM is in charge of initialization duties. I don't know much about Spring and shied away from servlet context listeners because I didn't want the external dependencies. I'm not suggesting that my way is the best way, but if you have a requirement to write unit tests for all of your code, then it's easier to stay away from the Servlet API. -Wes -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Joe Germuska Sent: Thursday, February 22, 2007 11:58 AM To: Struts Users Mailing List; [EMAIL PROTECTED] Subject: Re: [S2] Equivalent of Servlet init() method? On 2/22/07, Wesley Wannemacher [EMAIL PROTECTED] wrote: I looked for something similar a while back and didn't find anything simple. There are servlet context listeners (but that isn't really struts-2-ish). I would strongly disagree that ServletContextListeners are not really struts-2-ish. They are probably the best way to do any one-time initialization for an application, unless there's already some other code to do what you need... smime.p7s Description: S/MIME cryptographic signature
Re: [S2] Equivalent of Servlet init() method?
On 2/22/07, Wesley Wannemacher [EMAIL PROTECTED] wrote: I don't know much about Spring and shied away from servlet context listeners because I didn't want the external dependencies. I'm not suggesting that my way is the best way, but if you have a requirement to write unit tests for all of your code, then it's easier to stay away from the Servlet API. That is absolutely true. Then again, static initializer blocks can bring headaches of their own. I have never been very comfortable with them. I find that using Spring steers one to design code that is eminently unit testable, to the point where one need not use Spring in testing; one can simply satisfy a few simple dependencies as Spring would, and let the tests run. This is ultimately more a factor of designing for dependency injection than a characteristic of Spring itself, but I like Spring so... One of the great strengths of Struts 2 is that it does a much better job of hiding the Servlet API, making for components which are much more plausibly unit-testable. Joe -- Joe Germuska [EMAIL PROTECTED] * http://blog.germuska.com The truth is that we learned from João forever to be out of tune. -- Caetano Veloso
