defaultinputhandler.java

Java写的文本编辑器

/*
 * DefaultInputHandler.java - Default implementation of an input handler
 * Copyright (C) 1999, 2000, 2001 Slava Pestov
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

package org.gjt.sp.jedit.gui;

import javax.swing.KeyStroke;
import java.awt.event.*;
import java.awt.Toolkit;
import java.util.Hashtable;
import java.util.StringTokenizer;
import org.gjt.sp.jedit.*;
import org.gjt.sp.util.Log;

/**
 * The default input handler. It maps sequences of keystrokes into actions
 * and inserts key typed events into the text area.
 * @author Slava Pestov
 * @version $Id: DefaultInputHandler.java,v 1.1.1.1 2001/09/02 05:37:37 spestov Exp $
 */
public class DefaultInputHandler extends InputHandler
{
	/**
	 * Creates a new input handler with no key bindings defined.
	 * @param view The view
	 */
	public DefaultInputHandler(View view)
	{
		super(view);

		bindings = currentBindings = new Hashtable();
	}

	/**
	 * Creates a new input handler with the same set of key bindings
	 * as the one specified. Note that both input handlers share
	 * a pointer to exactly the same key binding table; so adding
	 * a key binding in one will also add it to the other.
	 * @param copy The input handler to copy key bindings from
	 * @param view The view
	 */
	public DefaultInputHandler(View view, DefaultInputHandler copy)
	{
		super(view);

		bindings = currentBindings = copy.bindings;
	}

	/**
	 * Adds a key binding to this input handler. The key binding is
	 * a list of white space separated key strokes of the form
	 * <i>[modifiers+]key</i> where modifier is C for Control, A for Alt,
	 * or S for Shift, and key is either a character (a-z) or a field
	 * name in the KeyEvent class prefixed with VK_ (e.g., BACK_SPACE)
	 * @param keyBinding The key binding
	 * @param action The action
	 */
	public void addKeyBinding(String keyBinding, EditAction action)
	{
	        Hashtable current = bindings;

		StringTokenizer st = new StringTokenizer(keyBinding);
		while(st.hasMoreTokens())
		{
			KeyStroke keyStroke = parseKeyStroke(st.nextToken());
			if(keyStroke == null)
				return;

			if(st.hasMoreTokens())
			{
				Object o = current.get(keyStroke);
				if(o instanceof Hashtable)
					current = (Hashtable)o;
				else
				{
					o = new Hashtable();
					current.put(keyStroke,o);
					current = (Hashtable)o;
				}
			}
			else
				current.put(keyStroke,action);
		}
	}

	/**
	 * Removes a key binding from this input handler. This is not yet
	 * implemented.
	 * @param keyBinding The key binding
	 */
	public void removeKeyBinding(String keyBinding)
	{
		throw new InternalError("Not yet implemented");
	}

	/**
	 * Removes all key bindings from this input handler.
	 */
	public void removeAllKeyBindings()
	{
		bindings.clear();
	}

	/**
	 * Returns either an edit action, or a hashtable if the specified key
	 * is a prefix.
	 * @param keyBinding The key binding
	 * @since jEdit 3.2pre5
	 */
	public Object getKeyBinding(String keyBinding)
	{
		Hashtable current = bindings;
		StringTokenizer st = new StringTokenizer(keyBinding);

		while(st.hasMoreTokens())
		{
			KeyStroke keyStroke = parseKeyStroke(st.nextToken());
			if(keyStroke == null)
				return null;

			if(st.hasMoreTokens())
			{
				Object o = current.get(keyStroke);
				if(o instanceof Hashtable)
					current = (Hashtable)o;
				else
					return o;
			}
			else
			{
				return current.get(keyStroke);
			}
		}

		return null;
	}

	/**
	 * Returns if a prefix key has been pressed.
	 */
	public boolean isPrefixActive()
	{
		return bindings != currentBindings;
	}

	/**
	 * Handle a key pressed event. This will look up the binding for
	 * the key stroke and execute it.
	 */
	public void keyPressed(KeyEvent evt)
	{
		int keyCode = evt.getKeyCode();
		int modifiers = evt.getModifiers();

		if(modifiers == 0
			&& bindings == currentBindings
			&& (keyCode == KeyEvent.VK_ENTER
			|| keyCode == KeyEvent.VK_TAB))
		{
			userInput((char)keyCode);
			evt.consume();
			return;
		}

		if((modifiers & ~KeyEvent.SHIFT_MASK) == 0)
		{
			// if modifier active, handle all keys, otherwise
			// only some
			switch(keyCode)
			{
			case KeyEvent.VK_BACK_SPACE:
			case KeyEvent.VK_DELETE:
			case KeyEvent.VK_ESCAPE:
			case KeyEvent.VK_ENTER:
			case KeyEvent.VK_TAB:
				break;
			default:
				if(!evt.isActionKey())
					return;
				else
					break;
			}
		}

		if(readNextChar != null)
		{
			readNextChar = null;
			view.getStatus().setMessage(null);
		}

		KeyStroke keyStroke = KeyStroke.getKeyStroke(keyCode,
			modifiers);
		Object o = currentBindings.get(keyStroke);
		if(o == null)
		{
			// Don't beep if the user presses some
			// key we don't know about unless a
			// prefix is active. Otherwise it will
			// beep when caps lock is pressed, etc.
			if(currentBindings != bindings)
			{
				Toolkit.getDefaultToolkit().beep();
				// F10 should be passed on, but C+e F10
				// shouldn't
				repeatCount = 0;
				repeat = false;
				evt.consume();
			}
			currentBindings = bindings;
			return;
		}
		else if(o instanceof EditAction)
		{
			currentBindings = bindings;

			invokeAction((EditAction)o);

			evt.consume();
			return;
		}
		else if(o instanceof Hashtable)
		{
			currentBindings = (Hashtable)o;
			evt.consume();
			return;
		}
	}

	/**
	 * Handle a key typed event. This inserts the key into the text area.
	 */
	public void keyTyped(KeyEvent evt)
	{
		char c = evt.getKeyChar();

		// ignore
		if(c == '\b')
			return;

		KeyStroke keyStroke;

		// this is a hack. a literal space is impossible to
		// insert in a key binding string, but you can write
		// SPACE.
		if(c == ' ')
			keyStroke = KeyStroke.getKeyStroke(KeyEvent.VK_SPACE,0);
		else
			keyStroke = KeyStroke.getKeyStroke(c);

		Object o = currentBindings.get(keyStroke);

		if(o instanceof Hashtable)
		{
			currentBindings = (Hashtable)o;
			return;
		}
		else if(o instanceof EditAction)
		{
			currentBindings = bindings;
			invokeAction((EditAction)o);
			return;
		}

		// otherwise, reset to default map and do user input
		currentBindings = bindings;

		if(repeat && Character.isDigit(c))
		{
			repeatCount *= 10;
			repeatCount += (c - '0');
			view.getStatus().setMessage(null);
		}
		else
			userInput(c);
	}

	/**
	 * Converts a string to a keystroke. The string should be of the
	 * form <i>modifiers</i>+<i>shortcut</i> where <i>modifiers</i>
	 * is any combination of A for Alt, C for Control, S for Shift
	 * or M for Meta, and <i>shortcut</i> is either a single character,
	 * or a keycode name from the <code>KeyEvent</code> class, without
	 * the <code>VK_</code> prefix.
	 * @param keyStroke A string description of the key stroke
	 */
	public static KeyStroke parseKeyStroke(String keyStroke)
	{
		if(keyStroke == null)
			return null;
		int modifiers = 0;
		int index = keyStroke.indexOf('+');
		if(index != -1)
		{
			for(int i = 0; i < index; i++)
			{
				switch(Character.toUpperCase(keyStroke
					.charAt(i)))
				{
				case 'A':
					modifiers |= InputEvent.ALT_MASK;
					break;
				case 'C':
					if(macOS)
						modifiers |= InputEvent.META_MASK;
					else
						modifiers |= InputEvent.CTRL_MASK;
					break;
				case 'M':
					if(macOS)
						modifiers |= InputEvent.CTRL_MASK;
					else
						modifiers |= InputEvent.META_MASK;
					break;
				case 'S':
					modifiers |= InputEvent.SHIFT_MASK;
					break;
				}
			}
		}
		String key = keyStroke.substring(index + 1);
		if(key.length() == 1)
		{
			char ch = key.charAt(0);
			if(modifiers == 0)
				return KeyStroke.getKeyStroke(ch);
			else
			{
				return KeyStroke.getKeyStroke(Character.toUpperCase(ch),
					modifiers);
			}
		}
		else if(key.length() == 0)
		{
			Log.log(Log.ERROR,DefaultInputHandler.class,
				"Invalid key stroke: " + keyStroke);
			return null;
		}
		else
		{
			int ch;

			try
			{
				ch = KeyEvent.class.getField("VK_".concat(key))
					.getInt(null);
			}
			catch(Exception e)
			{
				Log.log(Log.ERROR,DefaultInputHandler.class,
					"Invalid key stroke: "
					+ keyStroke);
				return null;
			}

			return KeyStroke.getKeyStroke(ch,modifiers);
		}
	}

	// private members
	private Hashtable bindings;
	private Hashtable currentBindings;

	private static boolean macOS;

	static
	{
		macOS = (System.getProperty("os.name").indexOf("Mac") != -1);
	}
}