com.macmillan.nmeyers
Class XClipboard

java.lang.Object
  |
  +--com.macmillan.nmeyers.XClipboard

public class XClipboard

extends java.lang.Object

Implements some X-specific methods for cut and paste.

The X Window System has several mechanisms to support cut and paste:

CLIPBOARD selection

This is the mechanism used by applications that implement an explicit cut and paste mechanism. It's used by the java.awt.datatransfer.Clipboard methods.

PRIMARY selection

This is the mechanism used when you simply drag a selection without cutting or copying. For example, when you drag a selection in one terminal window and paste it into another with the middle mouse button, you're using primary selection.

SECONDARY selection

An adjunct to the primary selection mechanism.

CUTBUFFER0

An outdated way of moving data around. Unlike selection, which supports moving arbitrary data types through an active transfer between programs, the cutbuffer statically stores text data in properties on the root window. Tends to be used only by ancient X clients.

This class provides some simple methods for extracting text selection strings. It can be subclassed to support more generality: the protected readSelection() method can support arbitrary selection atom names and arbitrary target types. More information than you could ever want to know about this can be found in the XConvertSelection() man page and the ICCCM specifications.

Author:

Nathan Meyers

Field Summary

protected byte[]

privateXData Hold platform-specific data here: X window connection and window ID.

Constructor Summary

XClipboard()
The class constructor opens a connection to the X server.

Method Summary

protected void	finalize() Shut down the X connection at finalization.
static void	main(java.lang.String[] argv) A simple test of the selection mechanisms.
java.lang.String	readClipboardSelectionString() Read the clipboard selection as a string.
byte[]	readCutBuffer0() Read the contents of CutBuffer0.
java.lang.String	readPrimarySelectionString() Read the primary selection as a string.
java.lang.String	readSecondarySelectionString() Read the secondary selection as a string.
protected java.lang.Object	readSelection(byte[] dp, byte[] selection, byte[] target) Request and read the current selection.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

privateXData

protected byte[] privateXData

Hold platform-specific data here: X window connection and window ID.

Constructor Detail

XClipboard

public XClipboard()

The class constructor opens a connection to the X server. Since Java will not share its X connections, XClipboard needs one of its own.

Method Detail

finalize

protected void finalize()

Shut down the X connection at finalization.

Overrides:

finalize in class java.lang.Object

readCutBuffer0

public byte[] readCutBuffer0()

Read the contents of CutBuffer0. This is an ancient X cut/paste mechanism, and of very limited use.

readSelection

protected java.lang.Object readSelection(byte[] dp,
                                         byte[] selection,
                                         byte[] target)

Request and read the current selection. The entire selection is read and returned, rather than setting up an InputStream mechanism to pump the bits as needed (which might be preferable for big selections).

This protected class is not the primary interface, but supports adding generality not supported by the various read* functions.

Parameters:

dp - The private X data created by the class constructor.

selection - The selection being requested - name of an X atom. The usual cut/paste buffer is "PRIMARY". Also of interest: "SECONDARY" and "CLIPBOARD".

target - The target type - name of an X atom. "STRING" is the most common.

Returns:

a byte[], short[], or int[] with the selection value. The type is determined by the type returned by the selection.

readPrimarySelectionString

public java.lang.String readPrimarySelectionString()

Read the primary selection as a string. If an application has some text selected, this will return it.

readSecondarySelectionString

public java.lang.String readSecondarySelectionString()

Read the secondary selection as a string. The secondary selection is rarely used.

readClipboardSelectionString

public java.lang.String readClipboardSelectionString()

Read the clipboard selection as a string. If an application has cut or copied some text, this will return it. This duplicates, in a limited way, capabilities in java.awt.datatransfer.Clipboard.

main

public static void main(java.lang.String[] argv)

A simple test of the selection mechanisms. Call the four public read* calls and report any non-null results.