Chapter 12, Problem 5PE

Program Plan Intro

Mail Box System

Program plan:

Filename: “Mailbox.java”

This program file is used to define a class “Mailbox”. In the code,

• Import the required packages.
• Define a class “Mailbox”.
  • Define the class members.
  • Define a constructor “Mailbox ()”.
    • Set the values for class members.
  • Define a method “getUser()”.
    • Return the “user”.
  • Define a method “addMessage()”.
    • Add “m”.
  • Define a method “getAllMessages()”
    • Create a string “r”.
    • Iterate a “for” loop,
      • Add “m” to “r”.
        • Return “r”.

Filename: “Message.java”

This program file is used to define a class “Message”. In the code,

• Import the required packages.
• Define a class “Message”.
  • Define the class members.
  • Define a constructor “Message()”.
    • Set the class elements.
  • Define the method “read()”.
    • Create a string “line”.
    • If length of “line” is less than 1,
      • Return.
        • If the length of “line” is greater than or equal to 1,
        • • Add “line” to “text”.
  • Define the method “getRecipient()”.
    • Create a string “recipient”.
  • Define the method “toString()”.
    • Return the string.

Filename: “MessageTester.java”

This program file is used to define a class “MessageTester”. In the code,

• Define a class “MessageTester”.
  • Define a method “main()”.
    • Define the object “m” of class “Message”.
    • Read new message.
    • Create a string array “lines”.
    • Print the “lines[0]”.
    • Print expected value.
    • Print the “lines[1]”.
    • Print expected value.
    • Print the “lines[2]”.
    • Print expected value.
    • Print the “lines[3]”.
    • Print expected value.
    • Call the method “getRecipient()” and print the value.
    • Print the expected value.
    • Create the object of “Mailbox”.
    • Call the method “addMessage()” and print the value.
    • Read new message.
    • Call the method “addMessage()”.
    • Call the method “getUser()” and print the result.
    • Print the expected value.
    • Print the statement.
    • Call the method “getAllMessages()”.
    • Print the expected value.