Jepp, hello,You know about java.security.DigestOutputStream and the similar java.crypt.MD5OutputStream from the cryptix package, right? It should be fairly straightforward to achieve what you want using either of these.
Nope, I didn't (I am clueless in this area), thanks. Markus, any comments?
sorry for the late reply. Currently kind of busy :-(
Anyway, DigestOutputStream handles the digest in the following way:
First of all you have to activate the stream by turn it "on". After it is on, every call of the write method (any of them actually) will update your digest, meaning that it will update you hashcode you will receive. In the HashCodeManager class we use already the DigestInputStream. Obviously the InputStream uses the read instead of the write methods to update the Digest :-)
The big thing is, that we throw away the stream, therefor it is just used for reading the file. Obviously we could extend this a little bit. I am not really sure, where we should implement something like this. Probably the best place would be the common component. another thing is, when this should be executed? during the download, or afterwards? I thing afterward is a pretty good quess, but also this is a waste of resources, since then we are touching the same file three times (downloading, checking and finally copying to the correct name). Also in my opinion there should be an option like "strictSecurityCheck" which is set to true by default but could be turned off. This is especially necessary when you are working in a closed source environment, where not every file gets an MD5 hashcode.
What do you think?
R, Markus
regards
Adam
