Persistent Storage II: File Connection and PIM API - Beginning J2ME: From Novice to Professional - page 118

File or Directory
An open FileConnection can be referring to either a directory or a file. You can determine if the
connection is associated with a directory via the following method:

public boolean isDirectory()

Some file systems, such as Win32, support hidden files. Hidden files do not appear on
regular directory listings, and are often used for system files. You can determine whether a file
or directory is hidden by calling the following method:

public isHidden()

On a file system that does not support hidden files, isHidden() always returns false. You
can also control the hidden attribute of a file on file systems that support it, by using this method:

public void setHidden(boolean hiddenFlag)

Setting hiddenFlag to true will make the file hidden, while a false value will make it visible.
This method has no effect on file systems that do not support hidden files nor on file systems
where you must rename the file to make files hidden.

Modifying File Attributes
Some file attributes may prevent you from reading or writing to a file. You can determine
whether a file can be read by using this method:

public boolean canRead()

Or find out if a file can be written to using the following:

public boolean canWrite()

To change the read or write attribute of a file on a file system that supports it, use this:

public void setReadable(boolean readable)
throws IOException

public void setWriteable(boolean readable) throws IOException

Note Most of the input/output methods on the FileConnection interface will throw
ConnectionClosedException if the call is made on a closed connection, IllegalModeException if a
write is tried on a connection that is opened as read-only, and SecurityException if the operation would
violate security policy. When a SecurityException is thrown, the operation is not actually performed. For
methods that accept arguments, NullPointerException and IllegalArgumentException may also
be thrown if an error occurs during argument processing.

■