Pattern-Oriented Software Design (Fall 2012) Homework #2 (Due: 10/19/2012)

Transcription

1 Pattern-Oriented Software Design (Fall 2012) Homework #2 (Due: 10/19/2012) 1. Introduction In this homework, we will add new features to ADD. Command pattern will be applied to support redo/undo operations. The text-mode interface will be enhanced for users to delete glyphs. 2. Load activity diagram file In this homework, we will define a standard file format for storing (loading) an activity diagram, and ADD will support loading an activity diagram from such a file. Each activity diagram file contains two parts: the first part is the declaration of glyphs of the activity diagram, and the second part represents the connections between these glyphs. In the first part, each list describes the glyph type of glyph x and its text. The first character of the list denotes the glyph type (I: Initial node, F: Final node, A: Activity, E: Edge, D: Decision node) of x. In the connections part, each line implies one connection, which uses two numbers to denote the IDs of the two glyphs to be connected. Table 1 shows a sample activity diagram file (file1.add). The corresponding diagram is shown in Figure 1. Table 1 Sample file file1.add I E A, Go to a movie theater E D E, I like science fiction film A, See movie Inception E F E, I like animated film A, See movie WALL E E 0,1 1,2 2,3 3,4 4,5 5,6 6,7 7,8 4,9 9,10 10,11

2 Figure 1 The user interface is extended to support loading an activity diagram from a file. Table 2 shows the possible operation scenarios of loading files. Table 2 Load activity diagram file > 1 Please key in a file path: C:\ADD\file_not_exist.add File not found error!! > 1 Please key in a file path: C:\ADD\file1.add The activity diagram is displayed as follows:

3 E 1 A 2 Go to a movie theater E 3 D 4 E 5 I like science fiction film A 6 See movie Inception E 7 F 8 E 9 I like animated film A 10 See movie WALL E E Delete glyph In this homework, the text-mode interface will be enhanced for users to delete glyphs. An example is shown in Table 3. The user selects the Delete a glyph command, and enters the glyph ID to delete a glyph. When a user deletes a glyph, ADD deletes all connections that are

4 associated with the glyph. Note that, ADD should warn users if wrong IDs are entered. Each time after the user deletes a glyph, ADD shows all the glyphs and connections there are in the current diagram. Table 3 Delete glyphs > 4 The activity diagram is displayed as follows: A 2 The first activity F

5 > 6 Please enter the glyph ID > X The glyph ID you entered does not exist. Please enter a valid one again. > 2 The glyph 2 has been deleted F Apply Command pattern In this homework, you need to apply command pattern to support redo/undo operations. Table 4 lists the operations that are required to support redo and undo. Figure 2 gives a reference design. In Figure 2, a Command class encapsulates a request. For example, the AddGlyphCmd encapsulates the request of adding a new glyph to the activity diagram. ADD is

6 the receiver of the command. In order to implement redo/undo, two stacks are needed to store command history. Each time when an undo command is performed, the application gets the most recently execute operation from the undo stack (i.e., the top element in the undo stack), executes the unexecute() method to revert application s state to the previous state, and moves the command from the undo stack to the redo stack. When a user executes the redo command, the application retrieves the top element from the redo stack, and automatically executes the execute() method. Figure 3 is the reference class diagram for ADD when the command pattern is applied. Table 4 Operations that must support Undo/Redo Commands Add glyph Delete glyph Connect glyphs TextUi +displaymenu() +processcommand() Receiver ActivityDiagram -_Glyphs +addglyph(in type : int) +deleteglyph(in type : int) +connectglyphs(in fromid : int, in toid : int) +existpathbetween(in fromid : int, in toid : int) : bool CommandManager -_redocommands : stack<command*> -_undocommands : stack<command*> +execute(in cmd : Command*) : void +redo() : void +undo() : void Command Command +execute() : void +unexecute() : void Concrete Command AddGlyphCmd +execute() : void +unexecute() : void DeleteGlyphCmd +execute() : void +unexecute() : void ConnectGlyphsCmd +execute() : void +unexecute() : void Figure 2 Command pattern

7 Figure 3 Class diagram Table 5 shows the new text-mode interface enhanced for users to select redo/undo functionalities. After a user selects redo/undo command, ADD shows all glyphs and connections of the current activity diagram. In addition, ADD should show an error message if there are no commands to redo or undo. Table 5 Redo/Undo

8 > 2 What kind of glyph do you want to add? [I]Initial node [F]Final node [A]Activity [E]Edge [D]Decision node > F A glyph [Final node] has been added. ID: A 2 The first activity F 4 > 3 Please enter the first glyph ID > 3 Please enter the second glyph ID > 4 The glyph 3 has been connected to glyph 4.

9 > 7 Undo! A 2 The first activity F 4 1 2

10 > 7 Undo! A 2 The first activity 1 2 > 8

11 Redo! A 2 The first activity F > 8 Redo!

12 A 2 The first activity F Grading After completion, your program should provide the following features: 1. Applying Command pattern in the design of the ADD (20%) 2. New features of ADD (45%) i. Load activity diagram file (10%) ii. Delete a glyph (10%) iii. Undo (10%) iv. Redo (15%) 3. Draw a class diagram (5%) 4. Time Measurement (0%, but necessary) You are required to record your working time into a time log sheet (reference Table). The following work items should be noticed: i. Reading the requirement of the homework ii. The design of your implementation, including drawing UML diagrams iii. Coding iv. Testing v. Other work items that spend you a lot of time, e.g., reading GoF book. You must submit your time log; otherwise, your homework will not be graded. 5. Summary (0%, but necessary) Before start doing your homework, please estimate (guess) the time (in hours) that you will need to spend on the homework, and write the estimated hours in the homework summary file. In addition, you are required to turn in your time log

13 (the time in hours that you actually spent on the homework, including documentation, as precisely as possible). Please download the summary file template from the instructor s website. 6. Code Quality (30%) Please write a C++ program to perform the features described above. The efficiency of your program is not of concern in this homework. The grading of code quality will be based mainly on whether your programs have bad smells.