CIS 3020 Part 1 - Revision history

Jka: CIS 3020 moved to CIS 3020 Part 1: More structured this way

2007-02-22T15:40:48Z

CIS 3020 moved to CIS 3020 Part 1: More structured this way

Jka at 16:27, 21 February 2007

2007-02-21T16:27:54Z

Show changes

Jka: /* Characteristics of Object Oriented Programming */

2007-02-21T16:26:34Z

Characteristics of Object Oriented Programming

Jka: /* Final Improvement for Reusability */

2007-02-21T16:00:51Z

Final Improvement for Reusability

Jka: /* Implementation 3 - the right way! */

2007-02-21T15:30:31Z

Implementation 3 - the right way!

Jka: /* Tempting, but wrong! */

2007-02-21T15:12:18Z

Tempting, but wrong!

Jka: /* Implementation 2 */

2007-02-20T19:44:38Z

Implementation 2

Jka: /* Implementation */

2007-02-20T19:42:19Z

Implementation

Jka: /* Implementation */

2007-02-20T19:39:10Z

Implementation

Jka: /* Problem */

2007-02-20T19:35:05Z

Problem

@@ Line 376: / Line 376: @@
 *** etc.
 ** All of these are coordinated by the general contractor (the main program/procedure) who specifies what will be done when
 ==Characteristics of Object Oriented Programming==
 These characteristics were first developed by [[Alan Kay]].
@@ Line 399: / Line 400: @@
 ====Classes are organized into a single rooted inheritance hierarchy (or tree)====
 * States and behaviors associated with a particlar class are accessible to descendant classes
 ==Unified Modeling Language==
 Graphical notation used to describe object-oriented software systems

← Older revision		Revision as of 16:00, 21 February 2007
Line 848:		Line 848:
	</pre>		</pre>
	===Final Improvement for Reusability===		===Final Improvement for Reusability===
		+	* It is likely that we will need to draw other shapes than squares
		+	* For example, a rectangle
		+	* Since a square is a general case of a rectangle (width=height) we could use the drawRectangle method to implement drawSquare
		+	===Implementation 4===
		+	<pre>
		+	class SquareDrawingTurtle extends RectangleDrawingTurtle {
		+	public void drawSquare( double len) {
		+	this.drawRectangle(len,len);
		+	} // end drawSquare() method
		+	} // end SquareDrawingTurtle
		+	</pre>
		+	===Using the new Class===
		+	<pre>
		+	class DrawSquare4 {
		+	public static void main(String[] args) {
		+	// Initialization
		+	Island maui = new Island(200,200);
		+	SquareDrawingTurtle tim = new SquareDrawingTurtle();
		+	maui.putTurtleAtCenter(tim);
		+
		+	// Draw the square
		+	tim.drawSquare(75.0);
		+	} // End main
		+	} // End Class DrawSquare4
		+	</pre>
		+	===Implementation 5===
		+	<pre>
		+	class GeoTurtle extends Turtle {
		+	public void drawSquare( double len ) {
		+	this.drawRectangle(len,len);
		+	} // end drawSquare() method
		+
		+	public void drawRectangle ( double sideA, double sideB ) {
		+	// code to implement drawRectangle
		+	} // end drawRectangle() method
		+	} // end GeoTurtle class
		+	</pre>
		+	===Using the new class===
		+	<pre>
		+	class DrawSquare5 {
		+	public static void main(String[] args) {
		+	// Initialization
		+	Island maui = new Island(200,200);
		+	GeoTurtle tim = new GeoTurtle();
		+	maui.putTurtleAtCenter(tim);
		+
		+	// Draw the square
		+	tim.drawSquare(75.0);
		+	} // End main
		+	} // End Class DrawSquare5
		+	</pre>

← Older revision		Revision as of 15:30, 21 February 2007
Line 833:		Line 833:
	} // end class GeoTurtle		} // end class GeoTurtle
	</pre>		</pre>
		+	===Using the new Class===
		+	<pre>
		+	class DrawSquare3 {
		+	public static void main(String[] args) {
		+	// Initialization
		+	Island maui = new Islans(200,200);
		+	GeoTurtle tim = new GeoTurtle();
		+	maui.putTurtleAtCenter(tim);
		+
		+	// Draw the square
		+	tim.drawSquare(75.0);
		+	} // End main
		+	} // End Class DrawSquare3
		+	</pre>
		+	===Final Improvement for Reusability===

← Older revision		Revision as of 15:12, 21 February 2007
Line 775:		Line 775:
	** Since we do not know who the turtle will be, "tim" is replaced with "this" which references the current instance of the class (i.e. whichever turtle is being told to draw the square)		** Since we do not know who the turtle will be, "tim" is replaced with "this" which references the current instance of the class (i.e. whichever turtle is being told to draw the square)
	===Tempting, but wrong!===		===Tempting, but wrong!===
		+	<pre>
		+	class GeoTurtle extends Turtle {
		+	public void drawSquare() {
		+	// same code as before dropping the
		+	// initialization section and replacing "tim"
		+	// with "this"
		+	double len = 75.0;
		+
		+	// Draw Square
		+	this.tailDown();
		+	// Draw first side
		+	this.move(len);
		+	// Draw second side
		+	this.turnLeft(90);
		+	this.move(len);
		+	// Draw third side
		+	this.turnLeft(90);
		+	this.move(len);
		+	// Draw fourth side
		+	this.turnLeft(90);
		+	this.move(len);
		+
		+	// Cleanup
		+	// Face in starting direction and pickup tail
		+	this.turnLeft(90);
		+	this.tailUp();
		+	} // End drawSquare()
		+	} // end class GeoTurtle
		+	</pre>
		+	===Implementation 3 - the right way!===
		+	<pre>
		+	class GeoTurtle extends Turtle {
		+	public void drawSquare( double len ) {
		+	// same code as before dropping the
		+	// initialization section and replacing "tim"
		+	// with "this"
		+
		+	// Draw Square
		+	this.tailDown();
		+	// Draw first side
		+	this.move(len);
		+	// Draw second side
		+	this.turnLeft(90);
		+	this.move(len);
		+	// Draw third side
		+	this.turnLeft(90);
		+	this.move(len);
		+	// Draw fourth side
		+	this.turnLeft(90);
		+	this.move(len);
		+
		+	// Cleanup
		+	// Face in starting direction and pickup tail
		+	this.turnLeft(90);
		+	this.tailUp();
		+	} // End drawSquare()
		+	} // end class GeoTurtle
		+	</pre>

← Older revision		Revision as of 19:44, 20 February 2007
Line 768:		Line 768:
	} // end class DrawSquare2		} // end class DrawSquare2
	</pre>		</pre>
		+	===Next Improvement for Reusability===
		+	* Code allows one specific turtle, tim, to draw a square
		+	* Better to define a specialized Turtle class that supports drawing squares
		+	* Changes:
		+	** Initialization no longer needed
		+	** Since we do not know who the turtle will be, "tim" is replaced with "this" which references the current instance of the class (i.e. whichever turtle is being told to draw the square)
		+	===Tempting, but wrong!===

← Older revision	Revision as of 15:40, 22 February 2007
(No difference)

@@ Line 701: / Line 701: @@
 ; Note: Sometimes one or more of these steps will require refinement. Just repeat the Analysis & Design process for each of these.
 ==Implementation==
 <pre>
 class DrawSquare1 {
@@ Line 729: / Line 730: @@
    } // End main()
 } // end class DrawSquare1
 </pre>

← Older revision		Revision as of 19:39, 20 February 2007
Line 701:		Line 701:
	; Note: Sometimes one or more of these steps will require refinement. Just repeat the Analysis & Design process for each of these.		; Note: Sometimes one or more of these steps will require refinement. Just repeat the Analysis & Design process for each of these.
	==Implementation==		==Implementation==
		+	<pre>
		+	class DrawSquare1 {
		+	public static void main(String args[]) {
		+	// Initialization
		+	Island maui = new Island(200,200);
		+	Turtle tim = new Turtle();
		+	maui.putTurtleAtCenter(tim);
		+
		+	// Do the work - Draw Square
		+	tim.tailDown();
		+	// Draw first side
		+	tim.move(75.0);
		+	// Draw second side
		+	tim.turnLeft(90);
		+	tim.move(75.0);
		+	// Draw third side
		+	tim.turnLeft(90);
		+	tim.move(75.0);
		+	// Draw fourth side
		+	tim.turnLeft(90);
		+	tim.move(75.0);
		+
		+	// Cleanup
		+	// Face in starting direction and pickup tail
		+	tim.turnLeft(90);
		+	tim.tailUp();
		+	} // End main()
		+	} // end class DrawSquare1
		+	</pre>

← Older revision		Revision as of 19:35, 20 February 2007
Line 700:		Line 700:

	; Note: Sometimes one or more of these steps will require refinement. Just repeat the Analysis & Design process for each of these.		; Note: Sometimes one or more of these steps will require refinement. Just repeat the Analysis & Design process for each of these.
		+	==Implementation==