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

Java Source | 1998-03-18 | 15.2 KB | 488 lines

package symantec.itools.awt;

import java.awt.Panel;
import java.awt.Checkbox;
import java.awt.CheckboxGroup;
import java.awt.Component;
import java.awt.AWTEventMulticaster;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.Vector;
import java.beans.PropertyVetoException;
import java.beans.PropertyChangeListener;
import java.beans.VetoableChangeListener;
import java.beans.PropertyChangeEvent;
import java.util.ResourceBundle;

//    01/27/97    RKM    Changed moveIntoGroup to preserve checkbox's state
//    01/29/97    TWB    Integrated changes from Windows and RKM's changes
//     01/29/97    TWB    Integrated changes from Macintosh
//    06/01/97    RKM    Updated to support Java 1.1
//                    Updated mechanism to keep track of contents of panel
//    09/10/97    LAB    Made it extend BorderPanel to give it BorderPanel's properties (Addresses Mac
//                    Bug #3086).  Made it fire an ItemEvent when the "station" changes (Addresses
//                    Mac Bug #3093).
//    10/05/97    LAB    Added mechanism for values passed to setSelectedRadioButtonIndex to be
//                    validated on each call to addImpl to avoid code-gen order specific
//                    dependencies.

/**
 * Creates an rectangular panel area that automatically groups
 * the RadioButtons that it contains.
 * <p>
 * All the RadioButtons within the RadioButtonGroupPanel act together. Only
 * one of the RadioButtons can be "on" at a time.
 * <p>
 * @version 1.1, August 22, 1997
 * @author Symantec
 */
public class RadioButtonGroupPanel extends BorderPanel implements java.awt.ItemSelectable
{
    /**
     * Constructs a RadioButtonGroupPanel.
     */
    public RadioButtonGroupPanel()
    {
        group = new CheckboxGroup();
        try
        {
            setPaddingTop(0);
            setPaddingBottom(0);
            setPaddingLeft(0);
            setPaddingRight(0);
        }
        catch (PropertyVetoException exc) {}

        rbList = new Vector();
        item = new IL();
        tempSelectionIndex = -1;
    }

    /**
     * Returns the selected items or null if no items are selected.
     */
    public Object[] getSelectedObjects()
    {
        Object object[] = {getSelectedRadioButton()};
        return object;
    }

    /**
     * Sets the current choice to the specified RadioButton.
     * @param rb the current RadioButton (CheckBox) choice
     * @exception PropertyVetoException if the recipient wishes the property
     *              change to be rolled back.
     */
    public synchronized void setSelectedRadioButton(Checkbox rb) throws PropertyVetoException
    {
        Checkbox oldValue = getSelectedRadioButton();
        if(! symantec.itools.util.GeneralUtils.objectsEqual(rb, oldValue))
        {
            vetos.fireVetoableChange("selectedRadioButton", oldValue, rb);

            group.setSelectedCheckbox(rb);
            //Fire an event to our listeners, since the previous line doensn't seem to result in an event being fired.
            sourceItemEvent(rb);

            changes.firePropertyChange("selectedRadioButton", oldValue, getSelectedRadioButton());
        }
    }

    /**
     * Gets the current choice.
     */
    public Checkbox getSelectedRadioButton()
    {
        return group.getSelectedCheckbox();
    }

    /**
     * Sets the current choice to the specified RadioButton.
     * @param index the index of the RadioButton to be the selected.
     * @see #getSelectedRadioButtonIndex
     * @exception PropertyVetoException if the recipient wishes the property
     *              change to be rolled back.
     */
    public synchronized void setSelectedRadioButtonIndex(int index) throws PropertyVetoException
    {
        tempSelectionIndex = index;
        if(isAdded)
        {
            Integer oldValue = new Integer(getSelectedRadioButtonIndex());
            if(oldValue.intValue() != index)
            {
                Integer newValue = new Integer(index);
                vetos.fireVetoableChange("selectedRadioButtonIndex", oldValue, newValue);

                setSelectedRadioButton((Checkbox)rbList.elementAt(index));

                changes.firePropertyChange("selectedRadioButtonIndex", oldValue, newValue);
            }
        }
    }

    /**
     * Gets the index of the current choice.
     * @return the index of the selected RadioButton.  -1 if no selection.
     * @see #setSelectedRadioButtonIndex
     */
    public int getSelectedRadioButtonIndex()
    {
        Checkbox cb = getSelectedRadioButton();
        if(cb != null && rbList.contains(cb))
        {
            for(int i = 0; i < rbList.size(); i++)
            {
                if((Checkbox)rbList.elementAt(i) == cb)
                    return i;
            }
        }
        return -1;
    }

    /**
     * Returns the String representation of this RadioButtonGroup's values.
     * Convert to String.
     */
    public String toString()
    {
        return getClass().getName() + "[selectedRadioButton=" + getSelectedRadioButton() + "]";
    }

    /**
     * Removes the component at the specified index from this container.
     * @param index the index of the component to be removed
     * @see java.awt.Container#add
     */
    public void remove(int index)
    {
        Component comp = getComponent(index);

        if(comp instanceof Checkbox)
        {
            ((Checkbox)comp).removeItemListener(item);
            //Remove it from out internal list.
            rbList.removeElement(comp);
        }

        super.remove(index);
    }

    /**
     * Removes all the components from this container.
     * @see java.awt.Container#add
     * @see #remove
     */
    public void removeAll()
    {
        Component[] comp = getComponents();

        for (int i = 0; i < comp.length; ++i)
        {
            if(comp[i] instanceof Checkbox)
                ((Checkbox)comp[i]).removeItemListener(item);
        }

        //Reset our internal list.
        rbList = new Vector();

        super.removeAll();
    }

    /**
     * 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.
     *
     * It has been overridden here to hook-up event listeners.
     *
     * @see #removeNotify
     */
    public synchronized void addNotify()
    {
        super.addNotify();
        errors = ResourceBundle.getBundle("symantec.itools.resources.ErrorsBundle");

        //Hook up listeners
        if (indexVeto == null)
        {
            indexVeto = new IV();
            addSelectedRadioButtonIndexListener(indexVeto);
        }
        isAdded = true;
    }

    /**
     * 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.
     *
     * It has been overridden here to unhook event listeners.
     *
     * @see #addNotify
     */
    public synchronized void removeNotify()
    {
        //Unhook listeners
        if (indexVeto != null)
        {
            removeSelectedRadioButtonIndexListener(indexVeto);
            indexVeto = null;
        }

        super.removeNotify();
    }

    /**
     * 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);
    }

    /**
     * Adds a listener for the SelectedRadioButtonIndex property changes.
     * @param listener the listener to add.
     * @see #removeSelectedRadioButtonIndexListener(java.beans.PropertyChangeListener)
     */
    public synchronized void addSelectedRadioButtonIndexListener(PropertyChangeListener listener)
    {
        changes.addPropertyChangeListener("selectedRadioButtonIndex", listener);
    }

    /**
     * Removes a listener for the SelectedRadioButtonIndex property changes.
     * @param listener the listener to remove.
     * @see #addSelectedRadioButtonIndexListener(java.beans.PropertyChangeListener)
     */
    public synchronized void removeSelectedRadioButtonIndexListener(PropertyChangeListener listener)
    {
        changes.removePropertyChangeListener("selectedRadioButtonIndex", listener);
    }

    /**
     * Adds a vetoable listener for the SelectedRadioButtonIndex property changes.
     * @param listener the listener to add.
     * @see #removeSelectedRadioButtonIndexListener(java.beans.VetoableChangeListener)
     */
    public synchronized void addSelectedRadioButtonIndexListener(VetoableChangeListener listener)
    {
        vetos.addVetoableChangeListener("selectedRadioButtonIndex", listener);
    }

    /**
     * Removes a vetoable listener for the SelectedRadioButtonIndex property changes.
     * @param listener the listener to remove.
     * @see #addSelectedRadioButtonIndexListener(java.beans.VetoableChangeListener)
     */
    public synchronized void removeSelectedRadioButtonIndexListener(VetoableChangeListener listener)
    {
        vetos.removeVetoableChangeListener("selectedRadioButtonIndex", listener);
    }

    /**
     * Adds the specified item listener to receive item events
     * from this component.
     * @param l the item listener
     * @see #removeItemListener
     */
    public synchronized void addItemListener(ItemListener l)
    {
        itemListener = AWTEventMulticaster.add(itemListener, l);
    }

    /**
     * Removes the specified Item listener so it no longer receives
     * Item events from this component.
     * @param l the action listener
     * @see #addItemListener
     */
    public synchronized void removeItemListener(ItemListener l)
    {
        itemListener = AWTEventMulticaster.remove(itemListener, l);
    }

    /**
     * This is the Item Event handling innerclass.
     */
    class IL implements java.awt.event.ItemListener
    {
        /**
         * Handles Item State Changed events
         * @param e the ItemEvent
         */
        public void itemStateChanged(ItemEvent e)
        {
            sourceItemEvent((Checkbox) e.getSource());
        }
    }

    /**
     * This is the PropertyChangeEvent handling inner class for the constrained SelectedRadioButtonIndex property.
     * Handles vetoing SelectedRadioButtonIndex indexes that are not valid.
     */
    class IV implements java.beans.VetoableChangeListener, java.io.Serializable
    {
        /**
         * This method gets called when an attempt to change the constrained Frame property is made.
         * Ensures the given Frame string is valid for this button.
         *
         * @param     e a <code>PropertyChangeEvent</code> object describing the
         *             event source and the property that has changed.
         * @exception PropertyVetoException if the recipient wishes the property
         *              change to be rolled back.
         */
        public void vetoableChange(PropertyChangeEvent e) throws PropertyVetoException
        {
            int i = ((Integer)e.getNewValue()).intValue();
            if (!isValidSelectedRadioButtonIndex(i))
            {
                throw new PropertyVetoException(errors.getString("InvalidSelectedRadioButtonIndex") + i, e);
            }
        }
    }

    /**
     * Is the given index value valid.
     * @param index the given index to test
     * @return true if the given index is acceptable, false if not.
     * To be valid it has to be within the limits of the rbList:
     */
    protected boolean isValidSelectedRadioButtonIndex(int index)
    {
        if(rbList != null && index < rbList.size() && index >= 0)
            return true;
        else
            return false;
    }

    /**
     * Fires an item event to the listeners.
     * @param item the radio button that changed state
     */
    protected void sourceItemEvent(Checkbox item)
    {
        if(item != lastItem)
        {
            if (itemListener != null)
                itemListener.itemStateChanged(new ItemEvent(this, ItemEvent.ITEM_STATE_CHANGED, item, (item.getState() ? ItemEvent.SELECTED : ItemEvent.DESELECTED)));
            lastItem = item;
        }
    }

    protected void addImpl(Component component, Object constraints, int index)
    {
        moveIntoGroup(component);

        super.addImpl(component,constraints,index);
        if(isValidSelectedRadioButtonIndex(tempSelectionIndex))
            try { setSelectedRadioButtonIndex(tempSelectionIndex); } catch (PropertyVetoException exc) { /*Silently verify.*/ }

    }

    /**
     * Internal helper method.
     * Adds the given Checkbox into this panel's CheckboxGroup without changing
     * its "selected" state.
     * @param component the Checkbox to add to this RadioButtonGroupPanel
     */
    protected void moveIntoGroup(Component component)
    {
        if(!(component instanceof Checkbox))
        {
            return;
        }

        //Cast the component to a checkbox
        Checkbox checkBox = ((Checkbox)component);

        //Save the state
        boolean savedState = checkBox.getState();

        //Set up the checkbox group
        checkBox.setCheckboxGroup(group);

        //Restore the state if it was true
        if (savedState)
            checkBox.setState(savedState);

        checkBox.addItemListener(item);

        //Keep the component in our internal vector.
        rbList.addElement(checkBox);
    }

    /**
     * The Checkbox group for the radio buttons.
     */
    protected CheckboxGroup group;
    /**
     * Vector of Checkboxes added to the panel.  Used to set selected RadioButton by index.
     */
    protected Vector    rbList;
    /**
     * Listener(s) that get notified when an ItemEvent is generated.
     */
    protected ItemListener itemListener = null;
    /**
     * Internal use.
     * Remembers the requested selected index so that <code>setSelectedIndex</code>
     * may be called before the appropriate radio button has been added.
     */
    protected int tempSelectionIndex;
    /**
     * is the component added to a container hierarchy?
     */
    protected boolean   isAdded = false;
    /**
     * Error strings.
     */
    transient protected ResourceBundle errors;

    private IL            item        = null;
    private IV            indexVeto    = null;
    private Checkbox    lastItem    = null;
    private symantec.itools.beans.VetoableChangeSupport vetos = new symantec.itools.beans.VetoableChangeSupport(this);
    private symantec.itools.beans.PropertyChangeSupport changes = new symantec.itools.beans.PropertyChangeSupport(this);
}