io Programmo 14/IOPROG_14.ISO/soft/sdkjava/sdkjava.exe/SDKJava.cab/Samples/AFC/JNotepad/src/AcceleratorFeature.java

Java Source | 1998-03-05 | 4.8 KB | 188 lines

//
// (c) 1998 Microsoft Corporation.  All rights reserved.
//

import JNoteKeyFeature;
import com.ms.ui.event.*;
import java.awt.event.*;
import java.awt.*;
import com.ms.ui.*;
import java.util.Hashtable;

/**
*    IFeature plugin. Intercepts accelerator keys (also known as shortcut keys)
*    from the text area and converts them into menu item events.
*
*    @see    IFeature
*    @see    IKeyFeature
*    @see    JNoteKeyFeature
*
*    @version    1.0, 7/23/97
*/

public class AcceleratorFeature extends JNoteKeyFeature
{
    /**
    *    Hashtable to hold keys-event pairs for control-key combinations
    */
    protected Hashtable controlKeysTable;

    /**
    *    Hashtable to hold keys-event pairs for shift-control-key combinations
    */
    protected Hashtable shiftCtrlKeysTable;

    /**
    *    Component to send events to
    */
    protected UIComponent eventTarget;


    /**
    *    Object which handles feedback (components telling menu bars/toolbars what to gray out)
    */
    protected ICommandFeedback feedbackObj;

    /**
    *    Creates a new AcceleratorFeature which sends events to the given target
    *
    *    @param    eventtarget    UIComponent to send command selection events to
    */
    public AcceleratorFeature(UIComponent eventtarget)
    {
        localInit(eventtarget, null);
    }
    /**
    *    Creates a new AcceleratorFeature which sends events to the given target
    *
    *    @param    eventtarget    UIComponent to send command selection events to
    *    @param    feedbackobj    Object which handles command feedback - enabling and disabling menu items
    */
    public AcceleratorFeature(UIComponent eventtarget, ICommandFeedback feedbackobj)
    {
        localInit(eventtarget, feedbackobj);
    }

    /**
    *    Private init function. Handles initialization of variables.
    */
    private void localInit(UIComponent eventtarget, ICommandFeedback feedbackobj)
    {
        controlKeysTable = new Hashtable(11);
        shiftCtrlKeysTable = new Hashtable(11);
        eventTarget = eventtarget;
        feedbackObj = feedbackobj;
    }

    /**
    *    Adds an accelerator key.
    *
    *    @param    accelKey    key to add to accelerator list.
    *    @param    action        Name of command to activate when accelerator key is pressed.
    *    @param    hasShift    false if the command requires control to be held with the accelerator key,
    *                            true if the command requires control and shift to be held down.
    */
    public void addAccelerator(char accelKey, String action, boolean hasShift)
    {
        // convert to uppercase and place in Character object
        Character e1 = new Character(Character.toUpperCase(accelKey));
        // create a new action event which will simulate clicking on the
        //        menu item/toolbar button.
        Event e2 = new Event(eventTarget, 0, Event.ACTION_EVENT, 0, 0,
            0, 0, new UIMenuItem(action));

        // put key-event pair in the right hashtable
        if (!hasShift)
        {
            controlKeysTable.put(e1, e2);
        }
        else
        {
            shiftCtrlKeysTable.put(e1, e2);
        }
    }

    /**
    *    Removes an accelerator key.
    *
    *    @param    accelKey    Key to remove
    *    @param    hasShift    true if removing from control-shift-key accelerator list,
    *                            false if from the control-key acclerator list.
    */
    public void removeAccelerator(char accelKey, boolean hasShift)
    {
        controlKeysTable.remove(new Character(accelKey));
    }

    /**
    *    Called when a key is pressed. Part of IUIKeyListener. Finds out if an
    *    accelerator key has been pressed; if so, find the Event associated with
    *    it and send it to the event target.
    *
    *    @param    ke    KeyEvent which is being handled
    */
    public synchronized void keyPressed(UIKeyEvent ke)
    {
        int iModifiers = ke.getModifiers();

        if ((iModifiers & UIInputEvent.CTRL_MASK) > 0)
        {
            // it's a control-key combo
            Character e1 = new Character((char)ke.getKeyCode());
            Event e = null;

            // pull Event out of right table
            if ((iModifiers & UIInputEvent.SHIFT_MASK) == 0)
            {
                e = (Event)controlKeysTable.get(e1);
            }
            else
            {
                e = (Event)shiftCtrlKeysTable.get(e1);
            }

            // Send a item selected message to the
            // attached event target
            if (e != null)
            {
                // if there's a feedback object, ask it if the item is
                // disabled.
                if (feedbackObj != null)
                {
                    if (!feedbackObj.isEnabled(((UIComponent)e.arg).getName()))
                    {
                        // not enabled, so don't do anything
                        return;
                    }
                }

                try
                {
                    int i = Integer.parseInt(((UIComponent)e.arg).getName());
                    ((IUIComponent)e.arg).setID(i);
                }
                catch ( Exception ex )
                {
                }

                // send the event to the right place
                eventTarget.postEvent(e);
            }
        }

    }

    /**
    *    Resets the feature; done when it is removed from
    *    an edit control. Does nothing since there is no state to reset.
    *    Part of IFeature.
    */
    public void reset()
    {
        // no need to do anything. Accelerator keys don't
        // change between files.
    }

}