辅导CSE3OAD/CSE4OAD、讲解RESTful API、辅导Java编程、讲解Java设计

CSE3OAD/CSE4OAD Assignment 2

Due Date: 10 AM, Wednesday October 24

th

, 2018

Assessment: This assignment 2 is worth 25% of the final mark for CSE3OAD and CSE4OAD.

This is an individual assignment.

Copying, Plagiarism: Plagiarism is the submission of somebody else’s work in a manner that gives the impression that

the work is your own. The Department of Computer Science and Information Technology treats plagiarism very seriously.

When it is detected, penalties are strictly imposed. Students are referred to the Department of Computer Science and

Information Technology’s Handbook and policy documents with regard to plagiarism.

No extensions will be given: Penalties are applied to late assignments (5% of your total assignment mark given is

deducted per day, accepted up to 5 days after the due date only). If there are circumstances that prevent the assignment

being submitted on time, an application for special consideration may be made. See the departmental Student Handbook

for details. Note that delays caused by computer downtime cannot be accepted as a valid reason for a late submission

without penalty. Students must plan their work to allow for both scheduled and unscheduled downtime. Assignments

submitted more than 5 days late (i.e. after 10 AM, Wednesday October 31st

, 2018) will receive the mark of 0.

Return of Assignments: Students are referred to the departmental Student Handbook for details.

Objectives: To design and implement a RESTful API that will provide an access endpoint to a data source controller similar

to the one you implemented using JDBC in Assignment 1.

CSE3OAD/CSE4OAD Assignment 2, Semester 2, 2018 Page 2 of 6

Introduction

The aims of the assignment are:

To implement web services for making available resources regarding your fridge groceries and items. The

groceries and items are those that you have worked with in Assignment 1.

o Using Java Reflection and Servlet API

To apply the relevant validation strategies to the grocery, using the Validation Framework we built Lab 07.

Files Provided:

The following are provided in the fridge directory (zip file)

The servlet descriptor file web.xml (directory fridge/WEB-INF)

The jar files for JSON conversion and JDBC (MySQL) driver (directory fridge/WEB-INF/lib)

The following in the directory fridge/WEB-INF/classes

o The Java files for the Validation framework (complete files):

Min.java, MinValidator.java

Max.java, MaValidator.java

NotNull.java, NotNullValidator.java

CharCount.java, CharCountValidator.java

Validator.java, ValidationException.java

o The Data Source Controller, FridgeDSC.java

Complete (NOTE: do not use your solution from Assignment 1)

o The Models (complete)

Grocery.java (excluding the validation annotations required for Task 1)

Item.java

o The Controllers (incomplete)

GroceryController.java

ItemController.java

o The Router Servlet (incomplete)

FridgeRouterServlet.java

o A few custom Exception sub-classes to be used throughout this Assignment 2 (complete)

MissingArgumentException.java

ResourceNotFoundException.java

UpdateNotAllowedException.java

o A separate unrelated Model for CSE4OAD students (Task 4)

UserProfile.java

The SQL Script to create and populate your database

o CreateDatabaseScript.sql (MySQL on your own computer)

o CreateDatabaseScript-latcs7.sql (MySQL on latcs7.cs.latrobe.du.au)

CSE3OAD/CSE4OAD Assignment 2, Semester 2, 2018 Page 3 of 6

Task 1

NOTE: you are strongly advised to complete this task before the end of Week 9

1. Study the Validation Framework provided (complete code provided) as well as the lecture and lab materials that

covered Java Reflection, Annotations and the Validation Framework.

2. TODO: Clearly annotate the relevant fields of the Grocery.java model.

o You may want to test if your validation on the model is working (see how we did that in the labs) – a static

main has been provided in Grocery.java for you to add your testing code.

Task 2

NOTE: you are strongly advised to complete this task before the end of Week 10

The controllers are the bridge between the FridgeDSC class and the FridgeRouterServlet class.

Study the complete FridgeDSC.java file provided, paying attention to its constructor (some changes has been

made, which differs from Assignment 1)

o NOTE: the constructor requires database host, username and password as arguments

o NOTE: CSE4OAD students, see Task 4a. before attempting Task 2.

For each controller (GroceryController.java and ItemController.java)

TODO: Complete each of the method stubs provided. Each method stubs needs to make a call to a relevant

FridgeDSC.java method. Identify which one and code it in the controllers.

o You may want to test if the controllers are responding properly when calling each FridgeDSC method – a

static main method has been provided in each class for you to add your testing code.

CSE3OAD/CSE4OAD Assignment 2, Semester 2, 2018 Page 4 of 6

Task 3

Implement the servlet (FridgeRouterServlet class) - The purpose of this servlet class is to:

1. Identify which resource the URL is requesting, using HttpServletRequest

example, the resource from a browser call to http://localhost:8080/fridge/api/grocery will then be “grocery”

(the same applies for a call to http://localhost:8080/fridge/api/GroCerY)

the HTTP method can also be found here (in this example, a browser call means using HTTP GET method)

2. Using the Servlet API,

retrieve your database host, username and password from the servlet descriptor file web.xml. (add your

MySQL username & password where needed in file web.xml)

3. Using the Reflection API,

a. Find if the resource controller exists - from the above example, resource “grocery” should have a matching

controller class GroceryController [hint: using Class.forName(…)]

b. Create an instance of such controller class

NOTE:

HTTP GET (with no parameters identified) maps to controller method get()

HTTP GET (with parameter identified) maps to controller method get(id)

HTTP POST (with parameter identified) maps to controller method add(…)

HTTP PUT (with parameter identified) maps to controller method update(id)

HTTP DELETE (with parameter identified) maps to controller method delete(id)

c. If we have an HTTP GET method, with no identifiable parameters (from the above example), find if

GroceryController class has a no-argument method named get()

then, make a call to this method, and store the returned data

d. Do the same (a, b, c above) if the resource identified is “item”

NOTE: clearly distinguish the difference between controller classes GroceryController and

ItemController

4. Using the Gson package provided and HttpServletResponse

a. Convert any returned data (from controller method call) to JSON data (using Gson)

b. Convert any valid case messages (if any) to JSON data (using Gson)

c. Send the any JSON data back to the browser

d. Making sure any potential errors (throughout steps 1-4 described for this Task 3) are caught, identified and

send back to the browser (using GSON to convert messages to JSON) and using appropriate HTTP Status

Codes and adequate (descriptive) error messages.

You will use Postman to test your API (https://www.getpostman.com/) – More on Postman will be covered in your lab

sessions.

CSE3OAD/CSE4OAD Assignment 2, Semester 2, 2018 Page 5 of 6

Task 4 (only for CSE4OAD)

a. TODO: Update FridgeDSC to be a Singleton, that is, not more than 1 instance of FridgeDSC can ever be created.

(you would want to do this part of task 4 before attempting coding the controllers in task 2, as the controller calls to

the DSC will be different once it has been converted to a Singleton)

b. Study the UserProfile.java class provided.

TODO: Analyse the UserProfile.java class provided and carefully decide which of the provided validation

annotations should be used for each of the attributes

o An attribute may have none, one or more annotations

o You are to come up with the reasons for each attribute validation reason

o For each annotation added to UserProfile.java, briefly comment (code comment) why you are using

such validation annotation and their parameters (if any parameters used)

Look at attribute id as a given example for annotation and comments.

o Create a new Email.java annotation (should your implementation have any parameters?)

o Create its matching EmailValidator.java Validator sub-class (as we did in lab 7), using Regular

Expression as checking measure for the validation rule.

o Annotate the email attribute in the UserProfile.java class with the newly created Email Validation

annotation.

o Follow the directions (TODO) provided in the UserProfile.java class main(…) method to test Task 4b.

CSE3OAD/CSE4OAD Assignment 2, Semester 2, 2018 Page 6 of 6

Consultation and other resources

1. Consultation sessions will be announced (LMS) prior to the submission date of this Assignment 2.

2. You are strongly advised to regularly check the Assignment 2 LMS section for any hints, clarification or corrections

regarding Assignment 2.

What to submit

Electronic copy of all of the classes required to run the application, including those that are provided, are to be submitted to

latcs8 using the submit OAD <directory or filename> command

Note that the submission is not through LMS.

All of your classes must be able to be compiled from their current directory.

This means, they must not be contained in any package.

As for the database, you can use the one on latcs7 or on your local machine. The only requirement is that your program

should work on the database tables grocery and item which must have the same structure as the one in the provided

MySQL script (CreateDatabaseScript.sql).

For each class that you submit, you must include, as part of the comments, at the beginning of each file,

o your full name (with surname in capital),

o your student ID,

o your user name (if different from student ID), and

o the subject code (CSE3OAD or CSE4OAD)

Assignment submissions without any of these will have 5% of the mark deducted.