FreeCode, Example Code,Free Programming Source Code: The FreeCode-FreeCode blog is the largest collection of free Internet related source code. Free programs are available in the following languages: C/C++, Java, Javascript, Ajax and Perl...
The example code is tested in IE, Firefox and Opare. Probably also works in Netscape as well as others like Safari.
<html>
<head>
<script type="text/javascript">
var obj;
var TAB = 9;
function catchTAB(evt,elem)
{
obj = elem;
var keyCode;
if ("which" in evt)
{// NN4 & FF & Opera
keyCode=evt.which;
} else if ("keyCode" in evt)
{// Safari & IE4+
keyCode=evt.keyCode;
} else if ("keyCode" in window.event)
{// IE4+
keyCode=window.event.keyCode;
} else if ("which" in window.event)
{
keyCode=evt.which;
} else { alert("the browser don't support"); }
if (keyCode == TAB)
{
obj.value = obj.value + "\t";
alert("TAB was pressed");
setTimeout("obj.focus()",1);// the focus is set back to the text input
}
}
</script>
</head>
<body>
<input type="text" onkeydown="catchTAB(event,this);">
</body>
</html>
This example is from the book _Java in a Nutshell_ by David Flanagan.
import java.io.*;
public class FileCopy {
public static void copy(String source_name, String dest_name)
throws IOException
{
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) { ; }
}
}
/* File.getParent() can return null when the file is specified without
a directory or is in the root directory.
This method handles those cases.*/
private static File parent(File f) {
String dirname = f.getParent();
if (dirname == null) {
if (f.isAbsolute()) return new File(File.separator);
else return new File(System.getProperty("user.dir"));
}
return new File(dirname);
}
public static void main(String[] args) {
if (args.length != 2)
System.err.println("Usage: java FileCopy " +
"");
else {
try { copy(args[0], args[1]); }
catch (IOException e) { System.err.println(e.getMessage()); }
}
}
}
class FileCopyException extends IOException {
public FileCopyException(String msg) { super(msg); }
}
