Generics return wrong type when subclassing page
------------------------------------------------
Key: TAP5-901
URL: https://issues.apache.org/jira/browse/TAP5-901
Project: Tapestry 5
Issue Type: Bug
Affects Versions: 5.1.0.4
Reporter: Mike Leonardo
I have a custom library that has the following classes:
{{{
public abstract class AbstractViewPage<T extends StaticPage<T, V>, V extends
StaticPageVersion> {
private static final Pattern ID = Pattern.compile("^\\d+$");
@InjectDao(StaticPage.class) private Dao<T> dao;
@Inject private Response response;
private T page;
void onActivate(String key) throws IOException {
if (ID.matcher(key).matches())
page = dao.get(Long.parseLong(key));
else {
page = dao.get(eq("name", key));
}
if (page != null && page.getLive() == null)
page = null;
if (page == null)
response.sendError(404, "Page not found");
}
public T getPage() {
return page;
}
public void setPage(T page) {
this.page = page;
}
/** Returns the versioned content to display. */
public V getContent() {
if (page == null)
return null;
return page.getLive();
}
}
}}}
{{{
/** Displays a static page */
@Public
public class Page extends AbstractViewPage<IFPStaticPage, IFPStaticPageVersion>
{
@Inject private IAuth auth;
@Inject private HttpServletRequest request;
@Inject private HttpServletResponse response;
Object onActivate() {
IFPStaticPage page = getPage();
if (page != null && page.isRestricted() &&
auth.getAccount(request, response) == null)
return "start";
return null;
}
public boolean isTopLevel() {
return getPage() == getPage().getSectionPage();
}
void onEndElementFromBreadcrumb(Element e) {
if ("a".equals(e.getName()))
e.getContainer().raw(" › ");
}
}
}}}
As you can see, based on generics the method "getContent" should return a
IFPStaticPageVersion.
This works fine when I use this Page.class directly.
Recently I wanted to extend this Page.class to add a few features specific to
one project. When I extended this class (no template so that it would use the
Page.class template) I ended up getting an error on the subclass. The error
occurred because getContent returned a completely different class instead of
IFPStaticPageVersion.
I work around I found to fix this is to override the getContent method so that
it explicitly defines the return type. But I had to do this in both Page.class
and the subclass (Page2.class). Here's my addition to both classes:
{{{
@Override
public IFPStaticPageVersion getContent() {
return super.getContent();
}
}}}
Obviously I shouldn't have to do this to get the correct class back (especially
not to both Page.class AND Page2.class.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
