Hands-On Design Patterns with Java

Implementing the abstraction example

The User class, shown here, is abstract and has three class variables. A default constructor has been added. In addition, the computeCredits() method has been made abstract and therefore cannot have a method body:

public abstract class User {    // class variables    private String name;    private String userID;    private int downloadCredits;    // constructor    public User(String name, String userID, int downloadCredits) {        this.name = name;        this.userID = userID;        this.downloadCredits = downloadCredits;    }    // abstract method    public abstract int computeCredits();

The second half of the User class is provided in the following code block. It contains the accessor and mutator methods for each of the three class variables: ...