Object Hierarchy

[Anon]

In my php application, I have the following object design:

FileUpload Class
ImageUpload Class extends FileUpload
JPGUpload Class extends ImageUpload
GIFUpload Class extends ImageUpload

When a user uploads a file, the ImageUpload is created. Then, when the mimetype is read, I would like to convert my current ImageUpload object to a JPGUOload or GIFUpload object, depending on the mimetype. Is it possible to do such a thing?

[Anon]

No, that's not possible...

You could do this though:

FileUpload Class
ImageUpload Class extends FileUpload
Image Class
JPGImage Class extends Image
GIFImage Class extends Image

Then when ImageUpload determines the mime type, it instantiates a JPGImage or GIFImage depending on the type, e.g.

class ImageUpload extends FileUpload {
var $img;

function determineMIME($mime) {
if ($mime == "image/gif") {
$img = new GIFImage();
} elseof ($mime == "image/jpeg") {
$img = new JPGImage();
} else {
die("Unknown file type");
}
}
}

Diego

[Anon]

THanks, it's a great help!