> From: Berin Loritsch [mailto:[EMAIL PROTECTED]] > > Vadim Gritsenko wrote: > > > Hi to Avalon guys on this list, > > > > I guess I found a bug (thanks to Mark Butler) in an > > ExcaliburComponentManager. Manager has a feature to have different > > results for hasComponent and lookup methods: it could return false even > > if lookup returns component. > > > I will take a look at the patch. > > The issue behind this is that unless a Component has been defined in > the configuration file, there is a good chance you don't want it. This > allows us to have entries in the roles file that will resolve to an > implementation if we really need the component--but will be ignored > if we don't want it, or it is optional. > > Case and point would be the TraxTransformer and the DELI Component > (BrowserCapabilities Component to be more precise). Not everyone want's > to use the DELI component in their systems (I currently don't have a > direct need yet--but will later). In the mean time, if we simply ask > the ECM (ExcaliburComponentManager) if the component exists we won't > ever load the Component implicitly. This is a good thing. It makes > DELI truly optional. However, if the DELI component had an entry in > the configuration file, we explicitly state we want this component > in our systems. > > If a Component merely looks up another Component from the ECM without > checking if it exists yet, the ECM will attempt to devine the > implementation from the RoleManager. It assumes that the Component > is *required* for operation.
This is clear. The problem is that I have a situation (current Cocoon in CVS), that: 1. Component is declared in xconf 2. Component is initialized according to the System.out (chage deliCocoonConfig.xml to print debug) 3. hasComponent returns false! > > If this is a bug, patch is attached. If this is a feature (reading the > > comment on this method suggests that it could be so), then we have some > > amount of bugs in Cocoon code. > > > And these are probably points of artificial requiring other Components. > > The general rule of thumb is this: > > 1) If the existence of a Component is optional (i.e. your Component can > get along without it--but will have more features if it exists), > use the hasComponent() method first. If it returns false, don't > look it up. But it is there, up and running, and hasComponent returns false :( > > PS Patch also contains fix for NPE in hasComponent() > > ?? Ok, I will look at it. Role == null - check is present in lookup, but not in hasComponent Vadim --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, email: [EMAIL PROTECTED]
