This functionality is analogous to ice:inputFile's outputStream property ( ICE-2198 ), but has been enhanced to use an interface with explicit notification of beginning and ending of the writing, which helped certain scenarios that go beyond just the typical database BLOB scenario.

All directions for the file processing have to be stored in the session, as it occurs in pre restore view phase, when there is no component tree, and thus no access to the fileEntry component's properties. So, we've decided to store the text of the EL expression to the callback object in the session. That way no actual bean object graph will be stored there. This way the EL expression will be evaluated within the current lifecycle, and not in a previous one, which might have otherwise created issues with stale request object references.

The caveat of this whole scenario is that the EL expression is evaluated in the part of the lifecycle when view and page scopes are likely not available. The application, session and request scopes should all be fine.

Testing of failure scenarios shows that:

1. When the callback EL has an invalid bean reference, no exception is thrown at all, and the callback evaluates to null, so the FileEntryPhaseListener treats it as a file-system upload.

2. When the callback EL has an invalid getter method reference, an exception is thrown: javax.el.PropertyNotFoundException: Property 'callbackish' not found on type org.icefaces.fileentry.FileBean. This results in the the FileEntryPhaseListener stopping, the file not being processed, no RequestParameterMap being created, in the ajax postback returns an empty update of just the ViewState.

3. When the file is prefailed and the callback throws a RuntimeException in it's begin method, the FileEntryPhaseListener has a generic catch(Ecxeption) clause that marks the file as INVALID, then the lifecycles continues, the fileEntryListener is called, the FacesMessage is rendered, and the page is updated.

It's the same for a RuntimeException in the callback's begin (non-prefail) and write methods.

4. When the callback's end method throws a RuntimeException, this results in the the FileEntryPhaseListener stopping, the file not being processed, nothing getting logged, and the error html page being returned to the browser, which does not display it since it's not an xml updates response.

Fixing the failure scenarios:

1. Code now detects when the callback is set but evaluates to null (but no exception, which is scenario 2), and if in Development Project Stage, it logs a warning. The upload still continues on to the file-system.

2. Code now catches the ELException, and if in Development Project Stage, it logs an error. Then re-throws the exception, so that the file will not be saved to the file-system. Shows a FacesMessage that there's a server application issue.

3. and 4. For all scenarios, an error is logged and a FacesMessage is shown.

Added callback support to fileEntry component.
Subversion 24117

Added test code for callback feature of fileEntry component. Test code is in forms 18 - 24 in: icefaces2/ace/test/web/fileEntry.xhtml
Also fixed the test code, which was referencing the old infos property, that had been renamed to results.
Subversion 24118