ToolbarBuilder – Use the builder pattern to create toolbars

Recently I discovered  Jeremys uber-ButtonUI’s. He provides UI classes to mimic Mac OS Button looks (and more) including segmented Buttons. The UI’s are nice, but while playing around with, I thought a builder approach would fit to easily create toolbars of buttons and components. Basically the problem is that segmentation configuration depends on Button order ( ), so changing the order of elements within a toolbar now also involves updating the segmentation configuration. Jeremy provides a nice installUI method that helps adding the appropriate button UIs, but I thought this could be improved further and I wanted to play with the builder pattern and find a way to make it extensible without copy/pasting the whole builder.

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Tags: builder, Swing, toolbar

Appframework and accelerator keys

Today I re-researched on the topic of assigning accelerator keys to actions depending on the operating system using java appframework. The problem I have is simple. On Mac OS X the “meta” key maps to apples command key. On windows it maps to the “Alt” key. And thats is the beginning of all the trouble. Assume you want to define a “save” action. On Mac the shortcut should be “command-S”, on windows it should be “ctrl-S”. In terms of appframework (or java keystrokes) that means you need:

save.Action.accelerator=meta pressed S

if you are on Mac OS X and

save.Action.accelerator=ctrl pressed S

if you are on Windows. The simple way to to this is

save.Action.accelerator=shortcut S

and “shortcut” will map to the meta key on the mac and to the ctrl key on windows. Remember, this is appframework specific and not a real Keystroke definition. I didn’t find the documentation anywhere ( I am sure it somewhere ), but I found that while browsing the source code. It doesn’t solve all the problems related to accelerator/mnemonic/keystrokes on differen paltforms ! But, at least for me, it solved 90% of the problems, because we develope our app in english (so no other locales involved) and “ctrl” is also fine for the linux/unix/solaris platform. I you want to do more or just want to read more about the problem, there is a thread from the appframwork mailing list.

Tags: appframework, Swing

A simple AbstractBean

Just in case, here is a simple example of an AbstractBean class that can be used as a base class for JavaBeans if you want to use the Eclipse bouded setter plugin.

public abstract class AbstractBean {
    /**
     * Create a new change support
     */
    protected PropertyChangeSupport change = new EDTSafePropertyChangeSupport(this);

    /**
     * @param listener
     * @see java.beans.PropertyChangeSupport#addPropertyChangeListener(java.beans.PropertyChangeListener)
     */
    public void addPropertyChangeListener(PropertyChangeListener listener) {
        change.addPropertyChangeListener(listener);
    }

    /**
     * @param propertyName
     * @param listener
     * @see java.beans.PropertyChangeSupport#addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
     */
    public void addPropertyChangeListener(String propertyName,
            PropertyChangeListener listener) {
        change.addPropertyChangeListener(propertyName, listener);
    }

    /**
     * @param propertyName
     * @param oldValue
     * @param newValue
     * @see java.beans.PropertyChangeSupport#firePropertyChange(java.lang.String, java.lang.Object, java.lang.Object)
     */
    public void firePropertyChange(String propertyName, Object oldValue,
            Object newValue) {
        change.firePropertyChange(propertyName, oldValue, newValue);
    }

    /**
     * @return
     * @see java.beans.PropertyChangeSupport#getPropertyChangeListeners()
     */
    public PropertyChangeListener[] getPropertyChangeListeners() {
        return change.getPropertyChangeListeners();
    }

    /**
     * @param propertyName
     * @return
     * @see java.beans.PropertyChangeSupport#getPropertyChangeListeners(java.lang.String)
     */
    public PropertyChangeListener[] getPropertyChangeListeners(
            String propertyName) {
        return change.getPropertyChangeListeners(propertyName);
    }

    /**
     * @param propertyName
     * @return
     * @see java.beans.PropertyChangeSupport#hasListeners(java.lang.String)
     */
    public boolean hasListeners(String propertyName) {
        return change.hasListeners(propertyName);
    }

    /**
     * @param listener
     * @see java.beans.PropertyChangeSupport#removePropertyChangeListener(java.beans.PropertyChangeListener)
     */
    public void removePropertyChangeListener(PropertyChangeListener listener) {
        change.removePropertyChangeListener(listener);
    }

    /**
     * @param propertyName
     * @param listener
     * @see java.beans.PropertyChangeSupport#removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
     */
    public void removePropertyChangeListener(String propertyName,
            PropertyChangeListener listener) {
        change.removePropertyChangeListener(propertyName, listener);
    }

    /**
     * Simply ensures that events are delivered through the event dispatching thread
     *
     */
    class EDTSafePropertyChangeSupport extends PropertyChangeSupport{
        public EDTSafePropertyChangeSupport(Object sourceBean) {
            super(sourceBean);
        }
        @Override
        public void firePropertyChange(final PropertyChangeEvent evt) {
            if(SwingUtilities.isEventDispatchThread()){
                super.firePropertyChange(evt);
            }else{
                SwingUtilities.invokeLater(new Runnable() {
                    public void run() {
                        firePropertyChange(evt);
                    }
                });
            }
        }
    }
}

This implementation restricts itself to the firePropertyChange(String,Object,Object) method. It also provide a custom extension of PropertyChangeSupport that ensures that events are fired in the EventDispatchingThread.

Tags: AbstractBean, bound properties, JavaBeans