Java Reference
In-Depth Information
posite design pattern
, which is presented on
page 163
of
Design Patterns:
Elements of Reusable Object-Oriented Software
by Erich Gamma, Richard
Helm, Ralph Johnson, and John Vlissides [Addison-Wesley, 1995; ISBN:
0201633612].)
•
Label
describes a single line of static text as a visual aid to the user.
•
List
describes a non-drop-down list of strings.
•
Scrollbar
describes a range of values.
•
TextComponent
describes any component that inputs text. Its
TextArea
subclassdescribesatextcomponentforinputtingmultiplelinesoftext,whereas
its
TextField
subclassdescribesatextcomponentforinputtingasingleline
of text.
Figure 7-2
presents the class hierarchy for menu component classes.
Figure
7-2.
AWT's
menu
component
class
hierarchy
is
rooted
in
java.awt.MenuComponent
.
AWT'sabstract
MenuComponent
class(whichdoesn'textend
Component
)isthe
root class for all AWT menu components. Directly beneath
MenuComponent
are
MenuBar
and
MenuItem
:
•
MenuBar
encapsulatesthewindowingsystemconceptofamenubarboundtoa
framewindow.Itcontainsasequenceof
Menu
components,whereeach
Menu
component contains a sequence of
MenuItem
components.
•
MenuItem
describes a single menuitem. Its
CheckboxMenuItem
subclass
describesamenuitemthat'simplementedviaacheckbox.Its
Menu
subclassde-
scribesapull-downmenucomponentthat'sdeployedfromamenubar.(
Menu
