Application: Personal Address Book
As previously stated, Java collections are data structures used to contain sets of data. There are several types of collections in Java. In your Discussion, you explored the use of Arrays and ArrayLists. Another useful collection method is the Map interface. Maps associate a key with a value; for example, a map used as a phone book might associate a person's name with a phone number. By searching for the person's name in the map, you could find his/her phone number, but you would not be able to search for a person's phone number to find his/her name. There are two basic kinds of maps:
HashMap, designed for fast access, and TreeMap, designed to keep entries in order by key. A TreeMap requires that the keys have a properly defined equalsmethod and implement the Comparableinterface. Fortunately, strings satisfy both sets of requirements, and are often used as keys.
In this assignment, use a TreeMap to implement a personal address book. Use the person's name as the key, and store information about the person as the value (in a Personobject). Declare the following information in the Personclass:
String name;
String address; // physical address
String email; // email address
longphoneNumber;
Add two additional fields to store other important contact information. For example, alternate phone numbers, websites, and notes.
You must save the information from the address book in a file to preserve it between runs of the program. A text file allows the user to view the data in any text editor, but requires substantial programming to read the file and turn it back into a TreeMapof Personobjects.
Any time you want to write out or read in objects, the easiest way to save the information is as an object or as objects, using ObjectOutputStreamand ObjectInputStream. The advantage of object I/O is ease of use. The disadvantage is that the files can only be used by Java programs that declare the objects in exactly the same way, with no added, deleted, or changed field declarations.
Use object I/O in this assignment, writing and reading the entire address book as a single TreeMapobject.
Object I/O requires that all parts of the objects to be read and written must be serializable, meaning that they must be able to be converted into an information form that can be easily stored (i.e., encoded as a byte stream). Strings, longs, and TreeMaps are serializable. Make your Personobjects serializable by implementing
Serializable:
class Person implements Serializable.
By doing this, you can properly read and write within a personal address book file.
Your program must first ask the user whether to create a new address book, or to read in a file containing an existing address book. If the user wants to create a new address book, your program must create an empty TreeMap. If the user wants to access an existing address book, your program must find the file name using the same process as you used for the "Fill-In-The-Blank" story. This time, however, instead of using a BufferedReader, use the following code:
FileInputStreamfis = new FileInputStream(file_name);
ObjectInputStreamois = new ObjectInputStream(fis);
addressBook = (TreeMap)ois.readObject();
ois.close();
Note that addressBookis the name of your TreeMap.
Once you have a (possibly new and empty) address book, your program should allow the user to do the following things:
- Get Help on how to use the program. As soon as an address book is loaded, print out a concise but complete list of the commands a user can enter. One of them should be a "help" command to print out the list again. The list must be detailed enough to explain the features to a user who is unfamiliar with your program.
- Add an entry to the address book. Do not allow an empty string for the person's name. All other fields are optional for the user to complete. For fields that the user leaves blank, store the empty string (for Stringfields), or the number 0 (for longorintfields).
- Look up an entry. When the user enters a person's name, display all of the information about that person.
- Edit an entry. Allow the user to change information about a person.
- Delete an entry. Allow the user to delete the entry from the map.
- Save the address book. If the address book is new, use JFileChooser.showSaveDialogto specify where to save the file; otherwise save it back to the same file that was read in. Use the following code to save an object file:
FileOutputStreamfos = new FileOutputStream(file_name);
ObjectOutputStreamoos = new ObjectOutputStream(fos);
oos.writeObject(addressBook);
oos.close();
The user will interact with your program using a text interface (that is, Scanner, and System.out.println). The details of this interaction are up to you, but you must provide all of the necessary details of your program's features in your program's "help" command. Also remember to write methods to handle input and output that are separate from the methods that do calculations.
File input and output can be complicated. It is important to test your input and output to make sure that your address book contains the correct information. Do this by creating an address book with several entries and then ending your program. Then, run your program again and open the address book to verify the entries.
By now you should be quite comfortable with the TDD approach, and you should be using it for all the methods that manipulate (add, look up, edit, delete) your address book, but not for methods that handle file I/O or that communicate with the user.
Include screenshots of your program running as part of your submission. Include screenshots of creating an address book, adding several entries, looking up two valid entries and two invalid entries, and using the "help" command. Run your program again and show screenshots of opening the address book from the previous run and looking up two valid entries and two invalid entries. Show screenshots of your program being tested with JUnit.
Save your NetBeans Project and screen shots of the working program as a ".zip" file.