CD Ware Multimedia 1999 February/CDW0299.iso/Demos/Cafe/Source.bin/StateCheckBox.java

Java Source | 1998-03-18 | 15.8 KB | 540 lines

package symantec.itools.awt;


import java.awt.*;
import java.awt.event.*;
import java.beans.PropertyVetoException;
import java.beans.PropertyChangeListener;
import java.beans.VetoableChangeListener;
import java.beans.PropertyChangeEvent;
import symantec.itools.beans.VetoableChangeSupport;
import symantec.itools.beans.PropertyChangeSupport;

//    06/01/97    RKM    Updated to support Java 1.1
//                    Made properties bound & constrained
//                    Converted events
//                    Removed internal enabled (it's in component)
//                    Removed enable & disable overrides, no one else calls repaint
//                    Changed invalidates to repaint
//  07/25/97    CAR marked fields transient as needed
//                  innerclasses implement java.io.Serializable
//                  changed visibility of fields "pressed", "released", "state" and "type" from private to package

/**
 * A two- or three-state checkbox that doesn't have an associated text label.
 * A two-state checkbox behaves just like the standard checkbox. In three-state
 * mode clicking the checkbox can switch the checkbox to a third state that
 * appears both gray and checked.
 * <p>
 * The third state is often used to indicate that an attribute of the current
 * selection varies across the selected items. For example, a checkbox used to
 * indicate "bold text" might use the third state if the currently selected
 * text included both bold and plain characters.
 * <p>
 * It is also used to indicate a default action or state.
 * <p>
 * @version 1.0, Nov 26, 1996
 *
 * @author  Symantec
 *
 */
public class StateCheckBox
    extends Canvas
{
    //--------------------------------------------------
    // constants
    //--------------------------------------------------

    private static final int WIDTH            = 14;
    private static final int HEIGHT           = 14;
    /**
     * A style constant indicating that this is a two-state checkbox.
     */
    public static final int TWO_STATE         = 0;
    /**
     * A style constant indicating that this is a three-state checkbox.
     */
    public static final int THREE_STATE       = 1;
    /**
     * A state constant indicating that the current state is "unchecked".
     */
    public static final int STATE_UNCHECKED   = 0;
    /**
     * A state constant indicating that the current state is "checked".
     */
    public static final int STATE_CHECKED     = 1;
    /**
     * A state constant indicating that the current state is "default".
     * Default is the third state of a three-state checkbox.
     */
    public static final int STATE_DEFAULT     = 2;

    //
    // Constructors
    //

    /**
     * Constructs a two-state StateCheckBox that is currently unchecked.
     */
    public StateCheckBox()
    {
        this.type   = TWO_STATE;
        this.state  = STATE_UNCHECKED;

        width       = WIDTH;
        height      = HEIGHT;

        state       = 0;

        pressed     = false;
        released    = true;
    }


    //--------------------------------------------------
    // accessor methods
    //--------------------------------------------------

    /**
     * Sets the current style to two-state or three-state.
     * @param newStyle new StateCheckBox state; either TWO_STATE or THREE_STATE
     * @see #getStyle
     * @see #TWO_STATE
     * @see #THREE_STATE
     * @exception PropertyVetoException
     * if the specified property value is unacceptable
     */
    public void setStyle(int newStyle)
        throws PropertyVetoException
    {
        if (type != newStyle)
        {
            Integer oldStyleInt = new Integer(type);
            Integer newStyleInt = new Integer(newStyle);

            vetos.fireVetoableChange("Style",oldStyleInt,newStyleInt);

            type = newStyle;

            changes.firePropertyChange("Style",oldStyleInt,newStyleInt);

            repaint();
        }
    }

    /**
     * Gets the current style: two-state or three-state.
     * @return the current StateCheckBox style; either TWO_STATE or THREE_STATE
     * @see #setStyle
     * @see #TWO_STATE
     * @see #THREE_STATE
     */
    public int getStyle()
    {
        return type;
    }

    /**
     * Sets the current checkbox state to unchecked, checked, or default.
     * @param newState the new state: STATE_UNCHECKED, STATE_CHECKED, or STATE_DEFAULT
     * @see #getState
     * @see #STATE_UNCHECKED
     * @see #STATE_CHECKED
     * @see #STATE_DEFAULT
     * @exception PropertyVetoException
     * if the specified property value is unacceptable
     */
    public void setState(int newState)
        throws PropertyVetoException
    {
        if (state != newState)
        {
            Integer oldStateInt = new Integer(state);
            Integer newStateInt = new Integer(newState);

            vetos.fireVetoableChange("State",oldStateInt,newStateInt);

            state = newState;

            changes.firePropertyChange("State",oldStateInt,newStateInt);

            repaint();
        }
    }

    /**
     * Gets the current checkbox state: unchecked, checked, or default.
     * @return the current state: STATE_UNCHECKED, STATE_CHECKED, or STATE_DEFAULT
     * @see #getState
     * @see #STATE_UNCHECKED
     * @see #STATE_CHECKED
     * @see #STATE_DEFAULT
     */
    public int getState()
    {
        return state;
    }

    //
    // Methods
    //

    /**
     * Adds the specified action listener to receive action events
     * from this button.
     * @param l the action listener
     */
    public synchronized void addActionListener(ActionListener l)
    {
        actionListener = AWTEventMulticaster.add(actionListener, l);
    }

    /**
     * Removes the specified action listener so it no longer receives
     * action events from this button.
     * @param l the action listener
     */
    public synchronized void removeActionListener(ActionListener l)
    {
        actionListener = AWTEventMulticaster.remove(actionListener, l);
    }

    /**
     * Adds a listener for all event changes.
     * @param listener the listener to add.
     * @see #removePropertyChangeListener
     */
    public synchronized void addPropertyChangeListener(PropertyChangeListener listener)
    {
        //super.addPropertyChangeListener(listener);
        changes.addPropertyChangeListener(listener);
    }

    /**
     * Removes a listener for all event changes.
     * @param listener the listener to remove.
     * @see #addPropertyChangeListener
     */
    public synchronized void removePropertyChangeListener(PropertyChangeListener listener)
    {
        //super.removePropertyChangeListener(listener);
        changes.removePropertyChangeListener(listener);
    }

    /**
     * Adds a vetoable listener for all event changes.
     * @param listener the listener to add.
     * @see #removeVetoableChangeListener
     */
    public synchronized void addVetoableChangeListener(VetoableChangeListener listener)
    {
         //super.addVetoableChangeListener(listener);
        vetos.addVetoableChangeListener(listener);
    }

    /**
     * Removes a vetoable listener for all event changes.
     * @param listener the listener to remove.
     * @see #addVetoableChangeListener
     */
    public synchronized void removeVetoableChangeListener(VetoableChangeListener listener)
    {
        //super.removeVetoableChangeListener(listener);
        vetos.removeVetoableChangeListener(listener);
    }

    //
    // Implmentation
    //

    class Mouse extends MouseAdapter implements java.io.Serializable
    {
        /**
         * Processes MOUSE_DOWN events.
         * This is a standard Java AWT method which gets called by the AWT
         * method handleEvent() in response to receiving a MOUSE_DOWN
         * event. These events occur when the mouse button is pressed while
         * inside this component.
         *
         * This method notes that the mouse is pressed inside the box and repaints it.
         *
         * @param e the event
         * @param x the component-relative horizontal coordinate of the mouse
         * @param y the component-relative vertical coordinate of the mouse
         *
         * @return always true since the event was handled
         *
         * @see #mouseUp
         * @see java.awt.Component#handleEvent
         */
        public void mousePressed(MouseEvent e)
        {
            pressed  = true;
            released = false;

            repaint();
        }

        /**
         * Processes MOUSE_UP events.
         * This is a standard Java AWT method which gets called by the AWT
         * method handleEvent() in response to receiving a MOUSE_UP
         * event. These events occur when the mouse button is released while
         * inside this component.
         *
         * If the mouse was pressed inside the box then the component is repainted
         * and an event is posted.
         *
         * @param e the event
         * @param x the component-relative horizontal coordinate of the mouse
         * @param y the component-relative vertical coordinate of the mouse
         *
         * @return always true since the event was handled
         *
         * @see #mouseDown
         * @see java.awt.Component#handleEvent
         */
        public void mouseReleased(MouseEvent e)
        {
            if (pressed)
            {
                pressed = false;

                state = (state + 1) % (type == TWO_STATE ? 2 : 3);

                repaint();

                sendActionEvent();
            }

            released = true;
        }

        /**
         * Processes MOUSE_ENTER events.
         * This is a standard Java AWT method which gets called by the AWT
         * method handleEvent() in response to receiving a MOUSE_ENTER
         * event. These events occur when the mouse first moves over this
         * component.
         *
         * @param e the event
         * @param x the component-relative horizontal coordinate of the mouse
         * @param y the component-relative vertical coordinate of the mouse
         *
         * @return always true since the event was handled
         *
         * @see #mouseExit
         * @see java.awt.Component#handleEvent
         */
        public void mouseEntered(MouseEvent e)
        {
            if (!released)
                mousePressed(e);
        }

        /**
         * Processes MOUSE_EXIT events.
         * This is a standard Java AWT method which gets called by the AWT
         * method handleEvent() in response to receiving a MOUSE_EXIT
         * event. These events occur when the mouse first leaves this
         * component.
         *
         * @param e the event
         * @param x the component-relative horizontal coordinate of the mouse
         * @param y the component-relative vertical coordinate of the mouse
         *
         * @return always true since the event was handled
         *
         * @see #mouseEnter
         * @see java.awt.Component#handleEvent
         */
        public void mouseExited(MouseEvent e)
        {
            if (pressed)
            {
                pressed = false;
                repaint();
            }
        }
    }

    /**
     * Moves and/or resizes this component.
     * This is a standard Java AWT method which gets called to move and/or
     * resize this component. Components that are in containers with layout
     * managers should not call this method, but rely on the layout manager
     * instead.
     *
     * It is overriden here to note the requested width and height.
     *
     * @param x horizontal position in the parent's coordinate space
     * @param y vertical position in the parent's coordinate space
     * @param width the new width
     * @param height the new height
     */
    public void reshape(int x, int y, int width, int height)
    {
        this.width  = WIDTH;
        this.height = HEIGHT;

        super.reshape(x, y, width, height);
    }

    /**
     * Returns the recommended dimensions to properly display this component.
     * This is a standard Java AWT method which gets called to determine
     * the recommended size of this component.
     *
     * If this component has been reshaped, then the width and height of that
     * request are returned.
     *
     * @see java.awt.Component#minimumSize
     */
    public Dimension preferredSize()
    {
        return new Dimension(width, height);
    }

    /**
     * Paints this component using the given graphics context.
     * This is a standard Java AWT method which typically gets called
     * by the AWT to handle painting this component. It paints this component
     * using the given graphics context. The graphics context clipping region
     * is set to the bounding rectangle of this component and its [0,0]
     * coordinate is this component's top-left corner.
     *
     * @param g the graphics context used for painting
     * @see java.awt.Component#repaint
     * @see java.awt.Component#update
     */
    public void paint(Graphics g)
    {
        g.clipRect(0, 0, width, height);

        g.setColor(Color.white);
        g.fillRect(0, 0, width, height);

        int w = width - 1, h = height - 1;

        if (pressed)
        {
            g.setColor(Color.lightGray);
            g.fillRect(2, 2, w - 4, h - 4);
        }

        g.setColor(Color.gray);
        g.drawLine(0, h - 1, 0, 0);
        g.drawLine(0, 0, w - 1, 0);

        g.setColor(Color.lightGray);
        g.drawLine(1, h - 2, w - 2, h - 2);
        g.drawLine(w - 2, h - 2, w - 2, 1);

        g.setColor(Color.black);
        g.drawLine(1, h - 2, 1, 1);
        g.drawLine(1, 1, w - 2, 1);

        switch (state)
        {
            case STATE_DEFAULT :
            {
                g.setColor(Color.lightGray);
                g.fillRect(2, 2, w - 4, h - 4);
                g.setColor(Color.black);
                // fall through
            }
            case STATE_CHECKED :
            {
                for (int i = 0; i < 3; ++i)
                {
                    g.drawLine(3, 5 + i, 5, 7 + i);
                    g.drawLine(5, 7 + i, 9, 3 + i);
                }
                break;
            }
            default :
            {
                break;
            }
        }
    }

    /**
     * Tells this component that it has been added to a container.
     * This is a standard Java AWT method which gets called by the AWT when
     * this component is added to a container. Typically, it is used to
     * create this component's peer.
     *
     * @see #removeNotify
     */
    public synchronized void addNotify()
    {
        super.addNotify();

        //Hook up listeners
        if (mouse == null)
        {
            mouse = new Mouse();
            addMouseListener(mouse);
        }
    }

    /**
     * Tells this component that it is being removed from a container.
     * This is a standard Java AWT method which gets called by the AWT when
     * this component is removed from a container. Typically, it is used to
     * destroy the peers of this component and all its subcomponents.
     *
     * @see #addNotify
     */
    public synchronized void removeNotify()
    {
        //Unhook listeners
        if (mouse != null)
        {
            removeMouseListener(mouse);
            mouse = null;
        }

        super.removeNotify();
    }

    /**
     * Sends an action performed event to any action listeners, as needed.
     */
    protected void sendActionEvent()
    {
        if (actionListener != null)
            actionListener.actionPerformed(new ActionEvent(this, ActionEvent.ACTION_PERFORMED, null));
    }

    // Protected members
    /**
     * Handles tracking vetoable change listeners and notifying them of each change
     * to this component's properties.
     */
    protected VetoableChangeSupport vetos = new VetoableChangeSupport(this);
    /**
     * Handles tracking non-vetoable change listeners and notifying them of each change
     * to this component's properties.
     */
    protected PropertyChangeSupport changes = new PropertyChangeSupport(this);
    /**
     * The this component's mouse event listener.
     */
    protected Mouse mouse = null;
    /**
     * The action listener to keep track of listeners for our action event.
     */
    protected ActionListener actionListener = null;

    // Private members
    transient boolean pressed;
    transient boolean released;
    private int width;
    private int height;
    int state;
    int type;
}