Current functionality:
The PDF version of an invoice picks up the logo from a file in the 'resources/logos' directory (see the property 'base_dir' of the file jbilling.properties), called 'entity-X.jpg' where X is the number of the company. The only way to change or create this file is through the operating system.

Desired functionality:
Allow to change this file from the web-based user interface. Add a sub-menu to 'Invoices' named 'Logo'.The logo page shows the current logo and allows to upload a new one. This applies only to the root user profile.

Technical overview:
To learn how the menu system works, and add a new menu option, read the menu section of the document 'more details: client tier'.
The rest is pretty straight forward, the 'logo' page shows the current logo and has one field to put the name of a file from the local directory to be uploaded to the web server. Take a look to jakarta commons file upload. We most probably want to use this library instead of doing everything from scratch, but I'm not sure about this, it requires some analysis of the pros/cons of using it.
We also need to validate that the file to be uploaded is not bigger than a reasonable size. How big can a logo be? You'll have to come up with a reasonable number.

Client tier modifications:
You need to add the new menu, as mentioned above, plus the new screen that allows the file upload. A new screen also means a new tile (tiles-defs.xml). This is a very simple screen that just shows the current logo for the entity (company) that the logged user belongs to, and has a form with just one field for the file name and a 'upload' button. The new tile doesn't have many 'sections': it only extends 'main' and uses directly a jsp page for the 'body' section.
To summarize, there is a new tile and a new jsp page that is going to be the body of the new tile and where you'll put the content of the new page.

Server tier modifications:
The server tier do not have to be modified for this feature. You do have to handle the request in an new struts Action class, but that is still logically the client tier because it is served by the web server (tomcat). The new Action will do the validation (correct file type, file name length, file size...) and the n the file uploading itself.

Database tier modifications:
You need to insert the rows to add the menu option and its permissions.

Changes mostly to be done in these files:
init.sql (for the menu option)
a new jsp page.
tiles-defs.xml (to show the new page)
a new class file (struts Action) to handle the request and file uploading
strust-config.xml (to configure the new Action)

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This feature is completed under SVN revision 97.