true if the file specified by this object
* exists; false otherwise.
*/
public boolean exists() {
try {
if (iStream == null)
iStream = urlConn.getInputStream();
return true;
} catch (IOException e) {
return false;
}
}
/**
* Tests if the application can write to this file.
*
* @return true if the application is allowed to
* write to a file whose name is specified by this
* object; false otherwise.
*/
public boolean canWrite() {
try {
if (oStream == null)
oStream = urlConn.getOutputStream();
return true;
} catch (IOException e) {
return false;
}
}
/**
* Tests if the application can read from the specified file.
*
* @return true if the file specified by this
* object exists and the application can read the file;
* false otherwise.
*/
public boolean canRead() {
return exists();
}
/**
* Tests if the file represented by this
* object is a "normal" file.
*
* A file is "normal" if it is not a directory and, in
* addition, satisfies other system-dependent criteria. Any
* non-directory file created by a Java application is
* guaranteed to be a normal file.
*
* @return true if the file specified by this
* XFile object exists and is a "normal"
* file; false otherwise.
*/
public boolean isFile() {
return true;
}
/**
* Tests if the file represented by this XFileAccessor
* object is a directory.
*
* @return true if this XFileAccessor object
* exists and is a directory; false
* otherwise.
*/
public boolean isDirectory() {
return false;
}
/**
* Returns the time that the file represented by this
* XFile object was last modified.
*
* The return value is system dependent and should only be
* used to compare with other values returned by last modified.
* It should not be interpreted as an absolute time.
*
* @return the time the file specified by this object was last
* modified, or 0L if the specified file
* does not exist.
*/
public long lastModified() {
return urlConn.getLastModified();
}
/**
* Returns the length of the file represented by this
* XFileAccessor object.
*
* @return the length, in bytes, of the file specified by
* this object, or 0L if the specified
* file does not exist.
*/
public long length() {
long len = urlConn.getContentLength();
return len < 0 ? 0 : len;
}
/**
* Creates a file whose pathname is specified by this
* XFileAccessor object.
*
* @return true if the file could be created;
* false otherwise.
*/
public boolean mkfile() {
try {
if (oStream == null)
oStream = urlConn.getOutputStream();
return true;
} catch (IOException e) {
return false;
}
}
/**
* Creates a directory whose pathname is specified by this
* XFileAccessor object.
*
* @return true if the directory could be created;
* false otherwise.
*/
public boolean mkdir() {
return false;
}
/**
* Renames the file specified by this XFileAccessor object to
* have the pathname given by the XFileAccessor object argument.
*
* @param dest the new filename.
* @return true if the renaming succeeds;
* false otherwise.
*/
public boolean renameTo(XFile dest) {
return false;
}
/**
* Returns a list of the files in the directory specified by
* this XFileAccessor object.
*
* @return an array of file names in the specified directory.
* This list does not include the current directory or
* the parent directory ("." and
* ".." on Unix systems).
*/
public String[] list() {
return new String[0];
}
/**
* Deletes the file specified by this object. If the target
* file to be deleted is a directory, it must be empty for
* deletion to succeed.
*
* @return true if the file is successfully deleted;
* false otherwise.
*/
public boolean delete() {
return false;
}
/**
* Reads a subarray as a sequence of bytes.
*
* @param b the data to be written
* @param off the start offset in the data
* @param len the number of bytes that are written
* @param foff the offset into the file
* @return number of bytes read; -1 if EOF
* @exception IOException If an I/O error has occurred.
*/
public int read(byte b[], int off, int len, long foff)
throws IOException {
int c;
if (iStream == null)
iStream = urlConn.getInputStream();
if (foff > fp) {
iStream.skip(foff - fp);
fp = foff;
}
c = iStream.read(b, off, len);
if (c > 0)
fp += c;
return (c);
}
/**
* Writes a sub array as a sequence of bytes.
*
* @param b the data to be written
* @param off the start offset in the data
* @param len the number of bytes that are written
* @param foff the offset into the file
* @exception IOException If an I/O error has occurred.
*/
public void write(byte b[], int off, int len, long foff)
throws IOException {
if (oStream == null)
oStream = urlConn.getOutputStream();
oStream.write(b, off, len);
fp += len;
}
/**
* Forces any buffered output bytes to be written out.
*
* * @exception IOException if an I/O error occurs. */ public void flush() throws IOException { if (oStream != null) oStream.flush(); } /** * Close the Streams * * @exception IOException If an I/O error has occurred. */ public void close() throws IOException { if (iStream != null) { iStream.close(); iStream = null; } if (oStream != null) { oStream.close(); oStream = null; } } /** * Returns a string representation of this object. * * @return a string giving the pathname of this object. */ public String toString() { return url.toString(); } }