File source_file = new File(source_name);
File destination_file = new File(dest_name);
FileInputStream source = null;
FileOutputStream destination = null;
byte[] buffer;
int bytes_read;
try {
// First make sure the specified source file
// exists, is a file, and is readable.
if (!source_file.exists() || !source_file.isFile())
throw new FileCopyException("FileCopy: no such source file: " +
source_name);
if (!source_file.canRead())
throw new FileCopyException("FileCopy: source file " +
"is unreadable: " + source_name);
// If the destination exists, make sure it is a writeable file
// and ask before overwriting it. If the destination doesn't
// exist, make sure the directory exists and is writeable.
if (destination_file.exists()) {
if (destination_file.isFile()) {
DataInputStream in = new DataInputStream(System.in);
String response;
if (!destination_file.canWrite())
throw new FileCopyException("FileCopy: destination " +
"file is unwriteable: " + dest_name);
System.out.print("File " + dest_name +
" already exists. Overwrite? (Y/N): ");
System.out.flush();
response = in.readLine();
if (!response.equals("Y") && !response.equals("y"))
throw new FileCopyException("FileCopy: copy cancelled.");
}
else
throw new FileCopyException("FileCopy: destination "
+ "is not a file: " + dest_name);
}
else {
File parentdir = parent(destination_file);
if (!parentdir.exists())
throw new FileCopyException("FileCopy: destination "
+ "directory doesn't exist: " + dest_name);
if (!parentdir.canWrite())
throw new FileCopyException("FileCopy: destination "
+ "directory is unwriteable: " + dest_name);
}
// If we've gotten this far, then everything is okay; we can
// copy the file.
source = new FileInputStream(source_file);
destination = new FileOutputStream(destination_file);
buffer = new byte[1024];
while(true) {
bytes_read = source.read(buffer);
if (bytes_read == -1) break;
destination.write(buffer, 0, bytes_read);
}
}
// No matter what happens, always close any streams we've opened.
finally {
if (source != null)
try { source.close(); } catch (IOException e) { ; }
if (destination != null)
try { destination.close(); } catch (IOException e) { ; }
}
