What problems will occur when you don?t use layout managers?
181
4.1 Supply contracts (in the form of comments specifying
pre- and post conditions)
for the enqueue() method of the LinkedQueue class given in
the Appendix.
(2)
4.2 Let Thing be a class which is capable of cloning
objects, and consider the code
fragment:
Thing thing1 = new Thing(); //(1)
Thing thing2 = thing1; //(2)
Thing thing3 = (Thing) thing1.clone(); //(3)
Explain how the objects thing2 and thing3 differ from each
other after
execution of the statements.
(
20
What is Unicast and Multicast object? Where we will use?
Question 5 [15]
Consider the following classes, illustrating the Strategy
design pattern:
import java.awt.*;
abstract class Text {
protected TextApplet tA;
protected Text(TextApplet tApplet) {
tA = tApplet;
}
abstract public void draw(Graphics g);
}
class PlainText extends Text {
protected PlainText(TextApplet tApplet) {
super(tApplet);
}
public void draw(Graphics g) {
g.setColor(tA.getColor());
g.setFont(new Font("Sans-serif", Font.PLAIN, 12));
g.drawString(tA.getText(), 20, 20);
}
}
class CodeText extends Text {
protected CodeText(TextApplet tApplet) {
super(tApplet);
}
public void draw(Graphics g) {
g.setColor(tA.getColor());
g.setFont(new Font("Monospaced", Font.PLAIN, 12));
g.drawString(tA.getText(), 20, 20);
}
}
public class TextApplet extends java.applet.Applet {
protected Text text;
protected String textVal;
protected Color color;
public String getText() {
return textVal;
}
public Color getColor() {
return color;
}
public void init() {
textVal = getParameter("text");
String textStyle = getParameter("style");
String textColor = getParameter("color");
if (textStyle == "code")
text = new CodeText(this);
else
text = new PlainText(this);
if (textColor == "red")
color = Color.RED;
else if (textColor == "blue")
color = Color.BLUE;
else
color = Color.BLACK;
}
public void paint(Graphics g) {
text.draw(g);
10
}
}
The Text class is more complicated than it should be (there
is too much coupling between the
Text and TextApplet classes). By getting rid of the
reference to a TextApplet object in the
Text class and setting the colour in the paint() method,
one could turn the Text class into an
interface and simplify the strategy classes considerably.
5.1 Rewrite the Text and PlainText classes to do what is
described above. (6)
5.2 Explain the consequent changes that are necessary to
the TextApplet class. (4)
5.3 Write an additional strategy class called FancyText (to
go with your simplified
strategy classes) to allow fancy text to be displayed for
the value "fancy" provided
for the style parameter. It should use the font Font
("Serif", Font.ITALIC, 12).
(3)
5.4 Explain what changes are necessary to the TextApplet
class for this. (2)
21
What is inner class?what is the use of inner class?where we
create the object for inner class? and inner class can
extend any class or inner class can implement any interface?
56
What are advantages of using Java?s layout managers than
windowing systems?
which is advanced deep technology in java launched by the
sun microsystem??? The answer is very logical
If u need correct answer mail me at priya_gupta@gmail.com
along with your userid / name. ThanQ
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