globalclipboard.java

一个非常好的ssh客户端实现

/******************************************************************************
 *
 * Copyright (c) 1999-2003 AppGate Network Security AB. All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code as
 * defined in and that are subject to the MindTerm Public Source License,
 * Version 2.0, (the 'License'). You may not use this file except in compliance
 * with the License.
 * 
 * You should have received a copy of the MindTerm Public Source License
 * along with this software; see the file LICENSE.  If not, write to
 * AppGate Network Security AB, Otterhallegatan 2, SE-41118 Goteborg, SWEDEN
 *
 *****************************************************************************/

package com.mindbright.terminal;

import java.util.Vector;
import java.util.Enumeration;

import java.awt.Toolkit;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.StringSelection;

import java.lang.reflect.Method;

public class GlobalClipboard implements TerminalClipboardHandler {

    // Singleton instance of GlobalClipboard
    //
    private static GlobalClipboard globalClipboard = null;

    private Toolkit   toolkit;
    private Vector    menuHandlers;
    private boolean   selectionAvailable;
    private Clipboard jvmClipboard;

    private GlobalClipboard() {
	this.toolkit            = Toolkit.getDefaultToolkit();
	this.selectionAvailable = false;
	this.menuHandlers       = new Vector();
    }

    public static synchronized GlobalClipboard getClipboardHandler() {
	return getClipboardHandler(null);
    }

    public static synchronized GlobalClipboard
	getClipboardHandler(TerminalMenuHandler menuHandler)
    {
	if(globalClipboard == null) {
	    globalClipboard = new GlobalClipboard();
	}
	globalClipboard.addMenuHandler(menuHandler);
	return globalClipboard;
    }

    public void addMenuHandler(TerminalMenuHandler menuHandler) {
	if(menuHandler != null && !menuHandlers.contains(menuHandler)) {
	    this.menuHandlers.addElement(menuHandler);
	}
    }

    public void removeMenuHandler(TerminalMenuHandler menuHandler) {
	if(menuHandlers.contains(menuHandler)) {
	    menuHandlers.removeElement(menuHandler);
	}
    }

    public void setSelection(String selection) {
	// We always try to set both the Clipboard and the SystemSelection
	Clipboard cb = getClipboard();
	Clipboard ss = getSystemSelection();

	if(selection == null)
	    selection = "";
	StringSelection sl = new StringSelection(selection);

	if(cb != null) {
	    cb.setContents(sl, sl);
	}
	if (ss != null) {
	    ss.setContents(sl, sl);
	}
	if (cb != null || ss != null) {
	    selectionAvailable(true);
	}
    }

    public String getSelection() {
	String    sl = null;

	// Prefer to fetch from SystemSelection if available

	Clipboard cb = getSystemSelection();
	if (cb == null) { 
	    cb = getClipboard();
	}
	if(cb == null) {
	    return sl;
	}

	Transferable t = cb.getContents(this);

	if(t != null) {
	    try {
		sl = (String) t.getTransferData(DataFlavor.stringFlavor);
	    } catch (Exception e) {
		try {
		    toolkit.beep();
		} catch (Throwable ee) {
		    // Could not beep, we are probably an unpriviliged applet
		}
	    }
	} else {
	    try {
		toolkit.beep();
	    } catch (Throwable e) {
		// Could not beep, we are probably an unpriviliged applet
	    }
	}

	return sl;
    }

    public void clearSelection() {
	selectionAvailable(false);
    }

    private void selectionAvailable(boolean val) {
	selectionAvailable = val;
	Enumeration e = menuHandlers.elements();
	while(e.hasMoreElements()) {
	    ((TerminalMenuHandler)
	     e.nextElement()).updateSelection(selectionAvailable);
	}
    }

    // This is the clipboard that is used on most systems. On *nix X11 it is
    // the CLIPBOARD that e.g. CDE reads.

    private synchronized Clipboard getClipboard() {
	// !!! OUCH

        if (com.mindbright.util.Util.isNetscapeJava()) {
            try {
                netscape.security.PrivilegeManager.enablePrivilege("UniversalSystemClipboardAccess");
            } catch (netscape.security.ForbiddenTargetException e) {
            }
        }
        
	Clipboard cb;
	if(jvmClipboard == null) {
	    try {
		cb = toolkit.getSystemClipboard();
	    } catch (Throwable e) {
		//
		// If we can't access the system clipboard we use our own
		// "global" one.
		//
		cb = jvmClipboard = new Clipboard("MindTerm-local-clipboard");
	    }
	} else {
	    cb = jvmClipboard;
	}
	return cb;
    }

    // This is the PRIMARY selection on typical *nix systems and e.g. xterm reads it.
    // CDE writes to this as well as CLIPBOARD

    private synchronized Clipboard getSystemSelection() {

        if (com.mindbright.util.Util.isNetscapeJava()) {
            try {
                netscape.security.PrivilegeManager.enablePrivilege("UniversalSystemClipboardAccess");
            } catch (netscape.security.ForbiddenTargetException e) {
            }
        }
        
	Clipboard ss = null;
	try {
	    Class c = toolkit.getClass();
	    Method m = c.getMethod("getSystemSelection", new Class[] {} );
	    
	    ss = (Clipboard) (m.invoke(toolkit, new Object[]{}));
	} catch (Throwable e) {
	    // 
	}
	return ss;
    }
    
}