import java.util.NoSuchElementException;
import java.util.Scanner;
 
/**
 * This class repeatedly reads strings from the user and stores the strings into
 * the telephone directory. After each string is read and inserted, the
 * telephone directory is printed.
 *
 * @author     Cheng Jade
 * @assignment TA 3
 * @date       Jan 30, 2010
 * @bugs       None
 */
 
public class ChengJade3 {
 
    /**
     * The main entry point of the application.
     *
     * @param args The command line arguments (not used).
     */
    public static void main(String[] args) {
 
        // Define a scanner that reads input from the user.
        final Scanner scanner = new Scanner(System.in);
 
        // Define a telephone directory and the user input string variable.
        final TelephoneDirectory myDirectory = new ArrayTelephoneDirectory();
        String input = null;
 
        // Loop repeatedly until the directory is full.
        while (true) {
 
            // Ask the user to type a new item for the telephone directory.
            System.out.print("Please enter a entry: ");
 
            // Read the string and check for errors.
            try {
                input = scanner.nextLine();
 
            } catch (NoSuchElementException e) {
                System.err.println(e.getMessage());
                System.exit(1);
 
            } catch (IllegalStateException e) {
                System.err.println(e.getMessage());
                System.exit(2);
            }
 
            // Add the item to the telephone directory and check for errors.
            try {
                myDirectory.add(input);
 
            } catch (DirectoryFullException e) {
                System.err.println(e.getMessage());
                System.exit(3);
            }
 
            // Print out the contents of the telephone directory.
            System.out.println(myDirectory.toString());
        }
    }
}
 
/**
 * This class satisfies the TelephoneDirectory interface by providing the add
 * method. It also provides a toString method that returns a readable version of
 * the contents of the directory.
 *
 * @author     Cheng Jade
 * @assignment TA 3
 * @date       Jan 30, 2010
 * @bugs       None
 */
class ArrayTelephoneDirectory implements TelephoneDirectory {
 
    String[] array = new String[5];
    int size = 0;
 
    /**
     * Adds an item to the telephone directory.
     *
     * @param item The item to add to the directory.
     * @throws DirectoryFullException Thrown if the directory is full.
     */
    public void add(String item) throws DirectoryFullException{
        assert item != null;
 
        // Check if the directory is full, and if it is throw the
        // DirectoryFullException.
        if (this.size == this.array.length)
            throw new DirectoryFullException();
 
        // Add the item to the directory array, and keep track of how many items
        // have been added.
        this.array[this.size++] = item;
    }
 
    /**
     * Returns a readable version of the contents of the telephone directory.
     *
     * @return A readable version of the contents of the telephone directory.
     */
    public String toString() {
 
        // If the directory is empty, return a special note.
        if (this.size == 0) {
          return "The telephone directory is empty.\n";
        }
 
        // Return the number of items in the directory.
        StringBuilder builder = new StringBuilder();
        builder.append("The telephone directory contains " + this.size + " items:\n");
 
        // Loop over each item added to the directory, and add it to the string builder.
        for (int i = 0; i < this.size; i++)
            builder.append((i + 1) + ". " + this.array[i] + "\n");
 
        // Return the list created above.
        return builder.toString();
    }
}
 
/**
 * The interface to a telephone directory.
 *
 * @author     Cheng Jade
 * @assignment TA 3
 * @date       Jan 30, 2010
 * @bugs       None
 */
interface TelephoneDirectory {
 
    /**
     * Adds an item to the telephone directory.
     *
     * @param item The item to add to the directory.
     * @throws DirectoryFullException Thrown if the directory is full.
     */
    void add(String item) throws DirectoryFullException;
}
 
/**
 * An exception that indicates the user attempted to add an item to a telephone
 * directory when it was full.
 *
 * @author     Cheng Jade
 * @assignment TA 3
 * @date       Jan 30, 2010
 * @bugs       None
 */
@SuppressWarnings("serial")
class DirectoryFullException extends Exception{
 
    /**
     * Initializes a new instance of the class.
     */
    public DirectoryFullException() {
 
        // Automatically assign the message text.
        super("The directory is full.");
    }
}
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