1. Lecture 14
CS202

2. Javadoc
Javadoc is a tool that generates html documentation (similar to the reference pages at java.sun.com) from Javadoc comments in the code. 
Javadoc Comments
Javadoc recognizes special comments  /** .... */ which are highlighted blue by default in Eclipse (regular comments // and /* ... */ are highlighted green).
Javadoc allows you to attach descriptions to classes, constructors, fields, interfaces and methods in the generated html documentation by placing Javadoc comments directly before their declaration statements.  
Here's an example using Javadoc comments to describe a class, a field and a constructor:      /** Class Description of MyClass */ public class MyClass { /** Field Description of myIntField */ public int myIntField; /** Constructor Description of MyClass() */ public MyClass() { // Do something ... } }
Javadoc Tags
Tags are keywords recognized by Javadoc which define the type of information that follows.
Tags come after the description (separated by a new line).
Here are some common pre-defined tags:
@author [author name] - identifies author(s) of a class or interface.
@version [version] - version info of a class or interface.
@param [argument name] [argument description] - describes an argument of method or constructor.
@return [description of return] - describes data returned by method (unnecessary for constructors and void methods).
@exception [exception thrown] [exception description] - describes exception thrown by method.
@throws [exception thrown] [exception description] - same
from

3. Javadoc
package demos; /** John 1.0 */ public class Goose { private double weightInKg; weightInKg weight of the goose */ public void setWeightInKg(double weightInKg){ this.weightInKg = weightInKg; } public double getWeightInKg(){ return weightInKg;

4. Javadoc
Mouse-hover over references to other classes to see Javadoc comments

5. Javadoc
This is very handy when you use classes written by other programmers.

6. Javadoc
Generating Javadoc creates html in the same format as Oracle's Java documentation. You can do this generate Javadoc in Eclipse with project/generate javadoc. Choose "Command" and find javadoc.exe, which will be in your jdk's bin directory:

7. Javadoc
View Javadoc by finding it in Eclipse (you will need to refresh the project after generating it), right clicking on index.html and choosing Open With / Web Browser. Eclipse currently puts it in a doc subdirectory of the project.

8. View Declaration and View Call Hierarchy
To see the definition of a method in your code or an imported library which contains code, select code that calls the method, right click, and choose Open Declaration
To find all calls to a method, select the method name, right click, and choose "view call hierarchy"

9. Using Libraries Java has a very strong culture of open-source software
Students, professors, programming hobbyists, and developers who choose to give back to the profession make many projects available for free
This allows you to use functionality you lack the expertise to code or don’t have time for
Quality control is nonexistent and malware is probably sometimes spread this way!
You will learn several other ways to get libraries and integrate them into your projects, but here is the simple way

10. Using Libraries
Find the website for the library you want and download it.
If you have the choice to get the bytecode alone or with the source included, get the version that includes the source
You will usually need to unzip or untar the library. The result will include one or more .jar files, which are archives of class files. Often there is also documentation, tutorials, and other material as well.
Right click on the project name and choose "Build Path/Configure Build Path", then "Add External JARs", then find the .jar you need to add.
The library should now appear under "Referenced Libraries" in your project

11. Using Libraries
This example uses a library called pdfbox to extract plain text from a pdf.

12. Using Libraries

13. Using Libraries
package pdfboxdemo; import java.io.File; import java.io.IOException; import org.apache.pdfbox.pdmodel.PDDocument; import org.apache.pdfbox.text.PDFTextStripper; public class Extractor { // adapted from public static void main(String[] args) { PDDocument pd; File input = new File("rj.pdf"); // The PDF file from where you would // like to extract try { pd = PDDocument.load(input); PDFTextStripper stripper = new PDFTextStripper(); stripper.setEndPage(20); String text = stripper.getText(pd); if (pd != null) { pd.close(); } System.out.println(text); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace();

14. Unified Modeling Language (UML)
The first applications you wrote were easy to think out and code with no intermediate steps.
Lab 7 involved some communication with your lab partner and the use of an interface to define how the parts of the application fit together.
As your applications get larger and involve more people, they will require better planning tools. These often involve documents which specify requirements and describe how the parts of the application fit together.
The textbook has introduced bits and pieces of Unified Modeling Language (UML); this lecture covers it in slightly more depth.

15. Unified Modeling Language (UML)
Most of the following slides are slightly revised versions of slides by Yi Luo, Carnegie-Mellon University:

16. UML Diagrams Types of UML Diagrams: Use Case Diagram Class Diagram
Sequence Diagram
Collaboration Diagram
State Diagram
This is only a subset of diagrams chosen from among the most widely-used types
Source of slides: Yi Luo, Carnegie-Mellon University

17. Use-Case Diagrams A use-case diagram shows a set of use cases
A use case is a model of the interaction between
External users of a software product (actors) and
The software product itself
More precisely, an actor is a user playing a specific role
describing a set of user scenarios
capturing user requirements
contract between end user and software developers
Source of slide: Yi Luo, Carnegie-Mellon University

18. Use-Case Diagrams Use Case Boundary Actor Employee Client Supervisor
Library System
Borrow
Employee
Client
Order Title
Fine Remittance
Supervisor

19. Use-Case Diagrams
Actors: A role that a user plays with respect to the system, including human users and other systems. e.g., inanimate physical objects (e.g. robot); an external system that needs some information from the current system.
Use case: A set of scenarios that describing an interaction between a user and a system, including alternatives.
System boundary: rectangle diagram representing the boundary between the actors and the system.

20. Use-Case Diagrams Association:
communication between an actor and a use case; Represented by a solid line.
Generalization: relationship between one general use case and a special use case (used for defining special alternatives) Represented by a line with a triangular arrow head toward the parent use case.

21. Use-Case Diagrams
Include: a dotted line labeled <<include>> beginning at base use case and ending with an arrows pointing to the include use case. The include relationship occurs when a chunk of behavior is similar across more than one use case. Use “include” in stead of copying the description of that behavior.
<<include>>
Extend: a dotted line labeled <<extend>> with an arrow toward the base case. The extending use case may add behavior to the base use case. The base class declares “extension points”.
<<extend>>

22. Use-Case Diagrams
Figure 16.12
The McGraw-Hill Companies, 2005

23. Use-Case Diagrams
Both Make Appointment and Request Medication include Check Patient Record as a subtask (include)
The extension point is written inside the base case Pay bill; the extending class Defer payment adds the behavior of this extension point. (extend)
Pay Bill is a parent use case and Bill Insurance is the child use case. (generalization)
(TogetherSoft, Inc)

24. Class diagram
A class diagram depicts classes and their interrelationships
Used for describing structure and behavior in the use cases
Provide a conceptual model of the system in terms of entities and their relationships
Detailed class diagrams are used for developers

25. Class diagram
Each class is represented by a rectangle subdivided into three compartments
Name
Attributes
Operations
Modifiers are used to indicate visibility of attributes and operations.
‘+’ is used to denote Public visibility
‘#’ is used to denote Protected visibility
‘-’ is used to denote Private visibility
Sometimes modifiers are not shown. By default, attributes are hidden and operations are visible.

26. UML Class Diagram
Source: Liang

27. Example: Defining Classes and Creating ObjectsTV
Source: Liang
TestTV
Run

28. OO Relationships There are two kinds of Relationships
Generalization (parent-child relationship)
Association (student enrolls in course)
Associations can be further classified as
Aggregation
Composition

29. OO Relationships: Generalization
Supertype
Example:
Customer
Regular
Customer
Loyalty
Customer
Subtype1
Subtype2
-Inheritance is a required feature of OOP
-Generalization expresses a parent/child relationship among related classes.
Used for abstracting details in several layers

30. OO Relationships: Association
Represent relationship between instances of classes
Student enrolls in a course
Courses have students
Courses have exams
Etc.
Association has two ends
Role names (e.g. enrolls)
Multiplicity (e.g. One course can have many students)
Navigability (unidirectional, bidirectional)

31. Association: Multiplicity and Roles
student 1 *
University
Person
0..1 *
teacher
employer
Role
Multiplicity
Symbol Meaning
1 One and only one
0..1 Zero or one
M..N From M to N (natural language)
* From zero to any positive integer
0..* From zero to any positive integer
1..* From one to any positive integer
Role
“A given university groups many people; some act as students, others as teachers. A given student belongs to a single university; a given teacher may or may not be working for the university at a particular time.”

32. Class diagram
[from UML Distilled Third Edition]

33. OO Relationships: Composition
Association
Models the part–whole relationship
Composition
Also models the part–whole relationship but, in addition, every part may belong to only one whole, and If the whole is deleted, so are the parts
Example:
A number of different chess boards: Each square belongs to only one board. If a chess board is thrown away, all 64 squares on that board go as well.
Class W
Whole Class
Class P1
Class P2
Part Classes
[From Dr.David A. Workman]
Example
Figure 16.7
The McGraw-Hill Companies, 2005

34. OO Relationships: Aggregation
Container Class
Aggregation:
expresses a relationship among instances of related classes. It is a specific kind of Container-Containee relationship.
express a more informal relationship than composition expresses.
Aggregation is appropriate when Container and Containees have no special access privileges to each other.
Class C
AGGREGATION
Class E1
Class E2
Containee Classes
Example
Bag
Apples
Milk
[From Dr.David A. Workman]

35. Aggregation vs. Composition
Composition is really a strong form of association
components have only one owner
components cannot exist independent of their owner
components live or die with their owner
e.g. Each car has an engine that can not be shared with other cars.
Aggregations
may form "part of" the association, but may not be essential to it. They may also exist independent of the aggregate. e.g. Apples may exist independent of the bag.

36. Interaction Diagrams show how objects interact with one another
UML supports two types of interaction diagrams
Sequence diagrams
Collaboration diagrams

37. Sequence Diagram(make a phone call)
Caller
Phone
Recipient
Picks up
Dial tone
Dial
Ring notification
Ring
Picks up
Hello

38. Sequence Diagram:Object interaction
Synchronous
Asynchronous
Transmission delayed
Self-Call
[condition] remove()
*[for each] remove()
Self-Call: A message that an
Object sends to itself.
Condition: indicates when a message is sent. The message is sent only if the condition is true.
Condition
Iteration

39. Sequence Diagrams – Object Life Spans
Creation
Create message
Object life starts at that point
Activation
Symbolized by rectangular stripes
Place on the lifeline where object is activated.
Rectangle also denotes when object is deactivated.
Deletion
Placing an ‘X’ on lifeline
Object’s life ends at that point A B
Create X
Deletion
Return
Lifeline
Activation bar

40. Sequence Diagram
Message
Sequence diagrams demonstrate the behavior of objects in a use case by describing the objects and the messages they pass.
The horizontal dimension shows the objects participating in the interaction.
The vertical arrangement of messages indicates their order.
The labels may contain the seq. # to indicate concurrency.

41. Interaction Diagrams: Collaboration diagrams
start
6: remove reservation
3 : [not available] reserve title
User
Reservations
5: title available
6 : borrow title
1: look up
2: title data
4 : title returned
Catalog
5 : hold title
Collaboration diagrams are equivalent to sequence diagrams. All the features of sequence diagrams are equally applicable to collaboration diagrams
Use a sequence diagram when the transfer of information is the focus of attention
Use a collaboration diagram when concentrating on the classes

42. State Diagrams (Billing Example)
State Diagrams show the sequences of states an object goes through during its life cycle in response to stimuli, together with its responses and actions; an abstraction of all possible behaviors.
End
Start
Unpaid
Paid
Invoice created
paying
Invoice destroying

43. State Diagrams (Traffic light example)
Start
Traffic Light
State
Red
Transition
Yellow timer expires
Yellow
Car trips sensor
Green timer expires
Green
Event

44. Installing Eclipse Add Ons
There are thousands of add-ons available to add functionality to Eclipse, many of them open source or otherwise free.
Some look free but are actually evaluation versions
Choose Help/Eclipse Marketplace, then enter text in the search box
Many add ons can be installed with a few clicks

45. Eclipse Add Ons

46. Ways To Generate UML Diagrams
Microsoft Visio
UMLet – Free UML tool
Several Eclipse plug ins support UML diagrams. In Eclipse, go to Help / Eclipse Marketplace and enter "UML" in the find box. Some tools are evaluation versions of commercial software, while others are open-source.
Model Goon provides an easy way to generate class diagrams
Many others available