代写EE5805留学生、代做Programming、代做Java编程语言、Java代做

日期：2020-08-05 10:38

EE5805 Java Network Programming

Test 1, 2019/20 Summer Term

Question 1. (30 marks)

The simple substitution cipher is a cipher that has been in use for hundreds of years. It basically consists

of substituting every plaintext character for a different ciphertext character. The alphabet set is simplified

to contain only the space character, comma, full-stop, digits (0-9), uppercase letters (A-Z) and lowercase

letters (a-z).

alphabets = { ,.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz}

key = {9fj,.6SpC57aeU VJ4Z0ybLXTx2guqI3Hwtin8GQNP1KFRklEzdrvocWsDhBAMmYO}

You can see from the given key that

• ‘ ‘ is substituted by ‘9’

• ‘,’ is substituted by ‘f’

• ‘.’ is substituted by ‘j’

• ‘0’ is substituted by ‘,’

• ‘1’ is substituted by ‘.’

• ‘2’ is substituted by ‘6’

• and so on.

a) [20 marks] Implement the methods encrypt(String key, String text) and decrypt(String key, String

cipher) in the class Q1.java.

b) [10 marks] Create a test class Q1Test.java with two test cases for the two methods in part (a) using

JUnit.

• For encryption:

key: 9fj,.6SpC57aeU VJ4Z0ybLXTx2guqI3Hwtin8GQNP1KFRklEzdrvocWsDhBAMmYO

text: Cheers, you will see this message if your program is correct.

expected result: VkKKsDf9YoB9Mldd9DKK9hklD9rKDDQRK9lF9YoBs9csoRsQr9lD9PossKPhj

• For decryption:

key: 9fj,.6SpC57aeU VJ4Z0ybLXTx2guqI3Hwtin8GQNP1KFRklEzdrvocWsDhBAMmYO

cipher: VkKKsDf9YoB9Mldd9DKK9hklD9rKDDQRK9lF9YoBs9csoRsQr9lD9PossKPhj

expected result: Cheers, you will see this message if your program is correct.

Question 2. (40 marks)

A video content provider maintains a daily log of the clients’ streaming requests. The streaming requests

are stored in a file (video_data.txt) with one request per line. Each streaming request contains the

following three fields separated by commas:

• a timestamp (represented by a long integer),

• a video ID (a string), and

• a client’s IP address.

Write a Java program to find the top 5 most active clients from the log file, i.e. the five IP addresses with

the highest view count.

Implement the methods readDataFile(String filename) and findTop5Clients(List<VideoRecord> list) in the

class Q2.java. The specification of the methods is written in the comment section.

The expected program output is as follow:

END OF PAPER