Your FaceBooklet application will use the classes you wrote for Program 3. Start by creating a copy of your Program 3 project with a new name (say, "Program4").

Note that you can complete the requirements of this assignment in any order you like. There is no need to complete items in the order they are listed here. The ordering in this assignment is for presentation purposes only.

Create a WallPosting Class

Create a brand new class called WallPosting that meets the following requirements:

1. It must provide a field called authorName that holds a (string) user name. Note: your wall posting may not contain a user profile field or a shared persistent map field. Only the author's profile name will be stored in this field.

2. It must provide a field called message that holds a (string) message.

3. It most provide a field called date that holds a Date object (defined in the package java.util).

4. It must provide a constructor that takes the author (a UserProfile, not a string) and message as parameters. This constructor should initialize fields using the values provided, and using a brand new Date object to initialize the date field.

5. It must provide getters for the message and date fields.

6. It must provide a getAuthor() method that returns the author's UserProfile (not just the author's name). Hint: your method can contain a shared persistent map as a local variable in order to look up the user profile from the author's name.

7. It must provide its own toString() method that returns an HTML representation of the post. This HTML string should include a thumbnail image of the post's author, the author's name, the date of the post, and the post's message. The layout and arrangements of these contents are up to you, as long as they are all included.

Note that you may not use ZK tags (only HTML tags) or @{...} expressions anywhere in the output of this method.

To format a date, you can create an instance of the class SimpleDateFormat, which provides a convenient method to turn a Date object into a nice text value.

You should handle error situations that may occur here gracefully, such as when the user profile of an author has been deleted between when the posting was added and when the wall is displayed, or if a user has not set a suitable thumbnail image yet.