some more thoughts ...
thomas, if we make it like you wrote ...
class VirusScanner {
public void scan(InputStream in) throws VirusFoundException {
if(in instanceof DataStoreInputStream) {
DataIdentifier di = ((DataStoreInputStream) in).getDataIdentifier();
if (hasScanned(di)) {
// already exists, no need to copy
return;
} else {
doScan(in);
addScanned(di);
}
} else {
doScan(in);
}
every module must handle this internally.
it would be much finer to handle this more generic with a proxy in front of
'modules'.
such proxy could store the dataIdentifier/result and a module key and if we try
to process a binary a second time this proxy could check this and return
without calling
the module a second time.
greets
claus
