TextArea Class Diagram

Ancestor class specifications:

java.lang.Object
java.awt.Component
java.awt.TextComponent

TextArea Class Specification

Invariant

A TextArea object...

- is drawn as a rectangular region.

- should be added to a container object with its upper-left corner x pixels from the left and y pixels from the top. (The upper left corner of the container is (0, 0).)

- when it is contained within a proper GUI container the rectangle appears with dimensions of the rectangle given by width and height.

- if necessary, the rectangle image is clipped to the boundaries of its GUI container.

- the content text is displayed within this rectangular region. Lines can be separated by including end-of-line (“\n”) characters. (Scrollbars are displayed within the text area if needed.)

Constructor Methods

public TextArea( )

post: A new TextArea object is created

and x == 0 and y == 0 and width == 0 and height == 0

and content == ""

(Note that TextAreas don't appear until added.)

Update Methods

public void append( String s )

post: content == content@pre concatenated_to s

public void repaint( )

post: Causes the Java virtual machine to update the display of this object as soon as possible.

public void setBounds( int intX, int initY, int w, int h )

post: x == initX and y == initY and width == w and height == h

public void setLocation( int intX, int initY )

post: x == initX and y == initY

public void setSize( int w, int h )

post: width == w and height == h

public void setText( String s )

post: content == s

Query Methods

public int getX( )

post: result == x

public int getY( )

post: result == y

public int getWidth( )

post: result == width

public int getHeight( )

post: result == height

public java.awt.Container getParent( )

post: this Rectangle is added to a Container

implies result == the Container to which this is added

and this Rectangle is not added implies result == null

publicString getText( )

post: result == content