Thinlets

1
Thinlets

• GUI Seminar
• Princeton 27/4 2004
• Peter Kriens

2
Thinlets
3
Thinlets

• XML Based GUI
• Based on AWT (Java 1.1)
• One class!
• Internationalization
• Reflection for binding XML to code
• Recursive
• Decent set of widgets
• Extensible
• Compressed size 38K!
• GNU Lesser Public License

4
Architecture
Thinlet
5
Calculator, XML File
ltpanel gap"4" top"4" left"4"gt lttextfield
name"number1" columns"4" /gt ltlabel text""
/gt lttextfield name"number2" columns"4" /gt
ltbutton text"" action"calculate(number1.text,
number2.text, result)" /gt lttextfield
name"result" editable"false" /gt lt/panelgt
6
Calculator, Source Code
package thinlet.demo import thinlet. public
class Calculator extends Thinlet public
Calculator() throws Exception
add(parse("calculator.xml")) public void
calculate(String number1, String number2, Object
result) try int i1
Integer.parseInt(number1) int i2
Integer.parseInt(number2)
setString(result, "text", String.valueOf(i1
i2)) catch (NumberFormatException nfe)
getToolkit().beep() public
static void main(String args) throws Exception
new FrameLauncher("Calculator", new
Calculator(), 320, 240)
7
Event Handling

• Parse methods
• public Object parse(String path) throws
  IOExceptionpublic Object parse(String path,
  Object handler) throws IOExceptionpublic Object
  parse(InputStream inputstream) throws
  IOExceptionpublic Object parse(InputStream
  inputstream, Object handler) throws IOException
• The widget (in the same XML file) identified by
  the given name, its type is Object.
• ltbutton action"one" /gt ltlabel name"label1"
  text"..." visible"false" /gt ltbutton
  action"two(thinlet, this, label1)" /gt
• public void one() public void two(Thinlet
  thinlet, Object button, Object label)
• itemThe component part on which the event
  occurred, valid for list item, tree node, table
  row, combobox choice, and tabbedpane tab.
• this/name/item.attribute
• ltbutton action"three(this.text, this.icon,
  label1.visible, label1.colspan)" /gt ltlist
  action"four(item, item.text, item.icon)"gt
    ltitem text"File" icon"file.gif" /gt lt/listgt
• public void three(String buttontext, Image
  buttonicon, boolean labelvisible, int labelcols)
  public void four(Object item, String itemtext,
  Image itemicon)

8
Components

• Component
• PopupMenu
• Label
• Button
• CheckBox
• ToggleButton
• ComboBox
• TextField
• PasswordField
• TextArea
• TabbedPane

• Panel
• Desktop
• Dialog
• SpinBox
• ProgressBar
• Slider
• SplitPane
• List
• Table
• Tree
• Separator
• MenuBar

9
Showcase
10
Theodor, XUL editor
http//www.carlsbadcubes.com/theodore/
11
Skinning
http//www.realchat.com/thinlet/
12
Layout

• Simple Layout Model
• Based on rows and columns
• Panels are used to define a basic layout
• Min size supported
• Rectangular based

13
Coding Style No OO

• Code seems hard to maintain
• Large single class
• Implements method dispatching in code
• Performance might be an issue
• All methods and fields have to be looked up

if ("spinbox" classname) Dimension size
getFieldSize(component) size.width
block return size if ("progressbar"
classname) boolean horizontal ("vertical"
! get(component, "orientation")) return new
Dimension(horizontal ? 76 6, horizontal ? 6
76) if ("slider" classname) boolean
horizontal ("vertical" ! get(component,
"orientation")) return new Dimension(horizontal
? 76 10, horizontal ? 10 76) if
("splitpane" classname)
14
Then Again

• The small size of the total package seems to make
  this problem manageable
• Would like a single component class though

15
Conclusion

• LGPL might be an issue
• Not clear how easy it is to do skinning
• Skinlet 09-Sep-03 - Version 0.4.2 beta, bugfix
  release. Minor bugfixes and improvements. I
  decided to temporarily suspend Skinlet
  development until it gets clear what the future
  refactored Thinlet will look like. This is mainly
  because the current one-class structure makes it
  really hard to keep up-to-date with each Thinlet
  update.
• Rectangular based layout is too restrictive for
  CE
• Basic skin is not very nice
• Performance
• Hard to extend with new widgets

• Basic model is very easy to use
• Thinlets recursive architecture makes it
  suitable to OSGi
• GUI editor available
• Internationalization
• Small
• Checks binding early