Hi Jerome, Dhanji
From reading your exchanges i think we are in general agreement about
the inheritance of resources and Java methods identified to process HTTP
requests.
As i alluded to there are a couple of edge cases, one highlighted by
Dhanji. If we agree that this is the right direction to take and since
it appears the issue of the location of annotations identifying Java
methods to process HTTP requests is orthogonal we could start
enumerating those edge cases.
Paul.
Jerome Louvel wrote:
> Hi Paul,
>
> Thanks for launching this thread.
>
>> What does it mean for the ClientsResource to inherit the getAccount
>> method from the AccountResource?
>
> For the identification, the annotation @ResourceRef could be inherited
> indeed, but if it is overridden in a subclass, the subclass's annotation
> should have priority.
>
> Also, it seems natural to inherit the representations. In my example, that
> means that ClientsResource would inherit the representation from
> AccountResource (getAccount), which seems unwanted. I will change the
> AccountResource to not have the @Output anno on its getAccount() method.
>
> Best regards,
> Jerome
>
>> -----Message d'origine-----
>> De : Paul.Sandoz_at_Sun.COM [mailto:Paul.Sandoz_at_Sun.COM]
>> Envoyé : mardi 15 mai 2007 19:12
>> À : dev_at_jsr311.dev.java.net
>> Objet : Inheritance of Java classes
>>
>> Hi,
>>
>> In the "resource" programming model Marc and I developed a Java class
>> may extend another Java class and thus inherit the HTTP methods.
>>
>> Jerome, in what you have proposed the ClientsResource (and others)
>> extend from AccountResource:
>>
>> @ApplicationClass(Application.class)
>> public class AccountResource {
>> @Output
>> public Account getAccount() {
>> return account;
>> }
>> }
>>
>> @ResourceRef("/clients")
>> public class ClientsResource extends AccountResource {
>> @Output
>> public List<Client> getClients() {
>> return getAccount().getClients();
>> }
>> }
>>
>> What does it mean for the ClientsResource to inherit the getAccount
>> method from the AccountResource?
>>
>>
>>
>> To explain inheritance more clearly an example might help using Java
>> classes for an Atom-based server. Some APP based examples i have seen
>> use one URI for read only access and another URI for
>> read/write access.
>> For example, given some Java classes (see end of email) the following
>> URI templates to Java classes can be supported:
>>
>> URI Java class
>> -------------------------------------------------------
>> /collection/ FeedResource
>> /collection/{entry} EntryResource
>> /collection/{entry}/media EntryResource
>> /collection/edit/{entry} EditEntryResource
>> /collection/edit/{entry}/media EditEntryResource
>>
>>
>> The EditEntryResource inherits from EntryResource, overrides the URI
>> template (while keeping the same URI template name
>> "{entry}"), inherits
>> the ProduceMime, and inherits the read only HTTP methods of
>> EntryResource. The familiar rules of inheritance are applied
>> (note that
>> the Consume/ProduceMime and UriTemplate use the meta-annotation
>> Inherited). (There are a couple of edge cases but i don't what to
>> highlight those in this email so as not to detract from the
>> main point.)
>>
>>
>>
>> Inheritance may also be useful in another area. An instance
>> of a class
>> returned to proceed further with the matching process may not be the
>> same class as declared by the return type. Thus it is
>> possible to return
>> a concrete instance with additional HTTP methods to those that are
>> supported by the declared returned class. For example, see the
>> FeedResource2 class at the end of the email.
>>
>> Paul.
>>
>>
>> [Note that the use of a constructor can stop the repeating
>> @UriParam("entry") annotation on EntryResource and EditEntryResource]
>>
>> @UriTemplate("/collection/")
>> @ProduceMime("application/atom+xml")
>> @SubResources({EntryResource.class, EditEntryResource.class})
>> public class FeedResource {
>> @Resource HttpContext context;
>>
>> @HttpMethod
>> public Feed getFeed() {
>> }
>>
>> @HttpMethod
>> @ConsumeMime("application/atom+xml")
>> public HttpResponse postEntry(Entry e) {
>> }
>>
>> @HttpMethod
>> public HttpResponse postMediaEntry(Entity<byte[]> entry) {
>> }
>> }
>>
>> @UriTemplate("{entry}")
>> @ProduceMime("application/atom+xml")
>> public class EntryResource {
>>
>> @HttpMethod
>> public Entry getEntry(@UriParam("entry") String entryId) {
>> }
>>
>> @HttpMethod
>> @UriTemplate("media")
>> @ProduceMime("*/*")
>> public Representation<InputStream> getMedia(
>> @UriParam("entry") String entryId) {
>> }
>> }
>>
>> @UriTemplate("edit/{entry}")
>> @ConsumeMime("application/atom+xml")
>> public class EditEntryResource extends EntryResource {
>>
>> @HttpMethod
>> public void putEntry(@UriParam("entry") String entryId,
>> Entry e) {
>> }
>>
>> @HttpMethod
>> public void deleteEntry(@UriParam("entry") String entryId) {
>> }
>>
>> @HttpMethod
>> @UriTemplate("media")
>> @ConsumeMime("*/*")
>> public void putMedia(@UriParam("entry") String entryId,
>> Entity<byte[]> update)
>> }
>> }
>>
>>
>>
>> @UriTemplate("/collection/")
>> @ProduceMime("application/atom+xml")
>> public class FeedResource2 {
>> @Resource HttpContext context;
>>
>> @HttpMethod
>> public Feed getFeed() {
>> }
>>
>> @HttpMethod
>> @ConsumeMime("application/atom+xml")
>> public HttpResponse postEntry(Entry e) {
>> }
>>
>> @HttpMethod
>> public HttpResponse postMediaEntry(Entity<byte[]> entry) {
>> }
>>
>> @UriTemplate("{entry}")
>> public EntryResource getEntryResource() {
>> return new EntryResource();
>> }
>>
>> @UriTemplate("edit/{entry}")
>> public EntryResource getEditEntryResource() {
>> return new EditEntryResource();
>> }
>> }
>>
>> --
>> | ? + ? = To question
>> ----------------\
>> Paul Sandoz
>> x38109
>> +33-4-76188109
>>
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Paul Sandoz
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