How to know a priori if a file can be deleted?

Question

My application requires that a collection of files be deleted. I currently loop through an array of File objects to be deleted, and invoke the delete() method on each object, i.e.
for (int i=0; i<collection_of_files.length; i++) {
returnval = collections_of_files.delete();
Problem: If one or more of the files has a "lock" on it, such as in Windows when some other process may be accessing the file, then those files can not be deleted, and returnval = false. How could I know before deleting ~any~ files in the collection, if some of the files can not be deleted? I would prefer not to actually delete any of the files in the collection, if one or more files can not be deleted because of a lock or any other reason. I have tried using SecurityManager to perform this a priori check on the deletability of a file, but no luck! Please advise.
thanks,
Ed

Answer 1

It tries to delete a temp file that doesn't exist, so
it doesn't delete anything in fact.Yes, the statement tempFile.delete() is not actually needed in the function isFileInUse. Other than that, the function isFileInUse does serve its purpose -- it determines true or false if there is a lock on a file. It does so by trying to rename the source file. If it can rename the source file, then we know there is no external lock on that file, and the function renames it back to what it was and returns false. This is a little tricky, but it works great. However, you would think there is a better way.
It was suggested also to try using the java.nio.filechannels.FileChannel class, which may be the proper way to go, but I haven't tried it yet. In particular, the method FileChannel.tryLock() returns "null if the lock could not be acquired because another program holds an overlapping lock."