Thanks, again, Martin for the pointer to the right direction.
On Wed, Mar 9, 2011 at 8:48 PM, Arthur Yeo <artyyeo_at_gmail.com> wrote:
> I guess an even simpler approach is to use a Singleton bean with @Startup
> declared... like the example here
>
> http://download.oracle.com/javaee/6/tutorial/doc/gipvi.html
>
> <http://download.oracle.com/javaee/6/tutorial/doc/gipvi.html>
>
> On Wed, Mar 9, 2011 at 7:20 PM, Arthur Yeo <artyyeo_at_gmail.com> wrote:
>
>> Thanks Martin, for opening my eyes to Singletons and Context.
>>
>> I found something in *The Java EE 6 Tutorial (*PartNo:
>> 821–1841–11, August 2010) on these topics and a simple prototype seems to
>> prove it is working. However, I found that even without the presence of
>>
>> 1. @ApplicationScoped or
>> 2. @Singleton
>>
>> declared, the lifetime of my Java object is still spanning across HTTP
>> service calls in Jersey. I am not complaining, just wondering if things have
>> been changed since the tutorial was released.
>>
>> Here's the code I have prototyped:
>>
>> ---------------------
>> @Stateless
>> @Path("/BlahRsrc")
>> public class TransRsrc {
>> @Context
>> private UriInfo context;
>>
>> @Inject MyCachedData mcache;
>>
>> @GET
>> @Produces("text/html")
>> @ApplicationScoped // <<---- does not seem to make a difference
>> @Path("/test")
>> public String Getdbo(){
>> System.out.println("Entering Getdbo()...");
>> if (mcache == null) {
>> mcache = new MyCachedData();
>> }
>> return ("AccId ==" + mcache.TellMeAccId().toString());
>> }
>>
>> }
>> -------------------
>> @Default
>> @Singleton // <<---- does not seem to make a difference
>> public class MyCachedData {
>> private dbObj dbo;
>>
>> public MyCachedData(){
>> System.out.println("Entering ctor of MyCachedData...");
>> if (dbo == null) {
>> dbo = new dbObj();
>> }
>> }
>>
>> public Integer TellMeAccId(){
>> return dbo.getAccId();
>> }
>> }
>> ---------------------
>> public class dbObj {
>> private Integer accId;
>>
>> public dbObj(){
>> System.out.println("Instantiating dbObj and accId is populated.");
>> accId = new Integer(50);
>> }
>>
>> public Integer getAccId(){
>> return accId;
>> }
>> }
>>
>> ========================
>>
>>
>>
>>
>> On Wed, Mar 9, 2011 at 10:01 AM, Martin Matula <martin.matula_at_oracle.com>wrote:
>>
>>> You can create your own provider class which can be a singleton and can
>>> be injected on your resources.
>>> See
>>> http://jersey.java.net/nonav/apidocs/latest/jersey/com/sun/jersey/spi/inject/SingletonTypeInjectableProvider.html
>>>
>>> Something like:
>>> @Provider
>>> public class MyCacheProvider extends
>>> SingletonTypeInjectableProvider<Context, MyCache> {
>>> public MyCacheProvider() {
>>> super(MyCache.class, new MyCache());
>>> }
>>> }
>>>
>>> Then in your resources you can do:
>>>
>>> @Context MyCache cache;
>>>
>>> @GET
>>> public String get() {
>>> return cache.getCachedItem();
>>> }
>>>
>>> Hope you get the idea.
>>> Martin
>>>
>>>
>>> On 9.3.2011 18:15, Arthur Yeo wrote:
>>>
>>> Martin,
>>>
>>> May be I should ask if there is "global" place in Jersey where I can
>>> store something that's accessible by all RESTful services answering to
>>> incoming requests?
>>>
>>>
>>> On Wed, Mar 2, 2011 at 11:52 AM, Arthur Yeo <artyyeo_at_gmail.com> wrote:
>>>
>>>> Hi Martin,
>>>>
>>>> Jersey is beautiful and I love it.
>>>>
>>>> Since RESTful services are event-driven, what's the best practices to
>>>> cache a bunch of static data (mainly configs stuffs) from the Db when my GF
>>>> webapp *initially starts up*?
>>>> I ask this because this operation is not exactly an HTTP event to
>>>> response to incoming requests --- it's an internal startup op. How do you
>>>> kick off something with no external events driving it?
>>>>
>>>> --
>>>> Arthur Y.
>>>>
>>>
>>>
>>>
>>> --
>>> Arthur Y.
>>>
>>>
>>
>>
>> --
>> Arthur Y.
>>
>
>
>
> --
> Arthur Y.
>
--
Arthur Y.