Homework 14

Due: 11:59pm on Sunday, December 19, 2004

1 problem, 50 points

Download Hw14Pr1.zip from the "Files for Download Page"
Although you have already started this program, it would be a good idea to download the Hw14Pr1.zip file, unzip it, and then copy your already-written code into the CS5App.java file. The reason for this is that we have included a "starter" database file and some additional code in Hw14Pr1.zip.

Pair Programming Problem
We encourage you to work with a partner on this problem --
it is the largest of the software projects this semester, and the extra pair of eyes helps!

In this project you will implement a film information system inspired by the Internet Movie Database http://www.imdb.com. For each film, you will need to store the following information:

title (a String)
the director (an object of type Director, a class you'll create)
the year it came out (an int)
the MPAA rating (a String, one of G, PG, PG-13, R, NC-17, or UR)
a review score (a double from 0.0 to 10.0)

Each film is stored as an object of class Film and this class contains the variables needed to hold the preceding information. The data members in this class (as well as all of the other classes you will define) should be declared as private.

The database of films will be stored as an object of class FilmDB, containing an array of Film objects together with a count of how many films are currently entered in the database. The count variable indicates the number of films that have been entered; initially the array is created to have a certain capacity for film objects: the capacity is the length of the array of Film objects. But initially every slot in the array is null, that is, the empty Film object. At this point, the count is 0. Each time the user enters a new film, one of these null objects is then replaced with the user's data and count is incremented. Each new film is inserted into the array in such a way that the films remain alphabetically sorted by title. New entries are only inserted as long as there is still some capacity (some null objects) remaining.

Each Film object contains within it a Director object. Each object of the Director class has

the director's first name (a String)
the director's last name (a String)
an object of type FilmDB that holds all of the entered films directed by this person

Analagous to the FilmDB, the DirectorDB class organizes the Director objects into an array that is alphabetically sorted according to last name (first names break ties). This array is also preallocated and contains a corresponding count variable.

By definition, these four classes are deeply entwined: a FilmDB contains Films, which contain Directors, which in turn contain their own FilmDBs. While this may sound complicated, it requires no special work on your part. Simply define each class as you always have: specifying variable and methods names and types as needed. The entwined nature of this assignment's classes are summarized in the following diagram:

class structure

The defintitions of each class should be included together along with the CS5App class in the CS5App.java file. For this problem, submit your CS5App.java file under Homework 14, Problem 1.

The Film Class

data members

private String title
private int year
private String rating
private double review
private Director dir

methods

public Film(String title, int year, String rating, double review, Director dir)
This is the constructor, which simply initializes a Film object by setting its data members equal to the constructor's inputs. Remember that if the input parameter and the data member have the same name, you must prefact the data member with this., as in this.year = year;.
public String getTitle()
public Director getDirector()
public int getYear()
public String getRating()
public double getReview()
The above four methods simply return the appropriate data member. They are accessor or getter methods so that a film's data can be accessed from other classes.
public void display()
This method should simply print the film's data in the following form (roughly):
```
               Title: Unforgiven
               Director: Eastwood, Clint
               Year: 1992
               Rating: R
               Review: 8.0
```
Note that to print the director's name, you'll need to access it from the Director object's accessor methods! I'd suggest using getFullName().

public void save()
This method should print the film's data is the same form as display, except that there should not be a description for each item. In addition, the director's last name and first name should appear on separate lines. This method will be used to write data out to a file. For example, the above film would appear as:
```
               Unforgiven
               Eastwood
               Clint
               1992
               R
               8.0
   
```

The Director Class

data members

private String fname
private String lname
private FilmDB filmDB

methods

public Director(String fname, String lname, int capacity)
This is the constructor -- be sure to heed the warning described in the Film class about using this! Also, be sure to make filmDB a new object of type FilmDB as follows:
```
             this.filmDB = new FilmDB(capacity);
    
```
public String getFullName()
This method should return the concatenation of the last name, a comma, a space, and the first name. That is, if fname is Clint and lname is Eastwood, then this method should return
```
             Eastwood, Clint
    
```
and this should be a single String (simply add together the things you need and return the result) This will help a lot when you want to print out the director's name or when you want to keep the names alphabetized... !
public String getFName()
public String getLName()
public FilmDB getFilmDB()
These three methods are the usual accessor methods. The last one is important for adding new films to a particular director's personal film database.

The FilmDB Class

data members

private Film[] films
private int count

methods

public FilmDB(int capacity)
This is the constructor. Be sure that you set the length of the data member films to be capacity. Note that this is NOT the count. The count is the number of films actually in the database -- count should start at 0.
public boolean isFull()
public boolean checkForFilm(String fulltitle)
public int getCapacity()
public int getCount()
These methods return useful information about the database. The method checkForFilm returns true if its input String is the title of a film already in the database, and false otherwise. It is useful for checking that a film is not entered twice.
public void addFilm(Film f)
This method should add the input Film f to the database by inserting it into the array films in alphabetical order! Hint: we will go over this in detail in class, but the easiest way to do this is to march through the array films backwards until you find the spot the new film should go. Be sure to add one to the count!
public void displayAllFilms()
public void saveAllFilms()
The first method (displayAllFilms) will use the display method from the Film class to do most of the work, and the second method (saveAllFilms) will be identical, except that it will use the method save from the Film class to do most of its work.

public void displayFilmsByTitle(String titlepiece)
public void displayFilmsByYear(int year)
public void displayFilmsByRating(String rating)
public void displayFilmsByReview(double minreview)
These five methods loop through the database -- that is, through the array films and print those films that match the criteria given. Note that because the films will all be kept in alphbetical order, they will always be output in that order. All String comparisons should be case-insensitive (see below) and looking up by title should allow the user to specify any substring of the title to find. The display-by-year and display-by-rating should display exact matches only (again, case-insensitive for the latter, which uses Strings). However, the display-by-review should show all of the films whose review is greater than or equal to the input argument.

The DirectorDB Class

data members

private Director[] dirs
private int count

methods

public DirectorDB(int capacity)
public boolean isFull()
public int getCount()
public int getCapacity()
public void addDirector(Director dir)
public void displayAllDirectors()
All of the above methods are similar in form and function to those in the FilmDB class. In particular, the addDirector method should keep the directors in the dirs array in alphabetical order. I would recommend using the getFullName method to do comparisons -- it will make it much easier than comparing the two names separately.
public Director findDirectorByName(String lname, String fname)
This method takes String arguments for a first and last name and searches the dirs array for an entry with that name. Note that this search should not be case-sensitive -- again, I'd advise using the "full name," i.e., lname+", "+fname, which is easy to compare to the Strings returned from getFullName. If there is a match, the corresponding Director object should be returned. If there is no match, null should be returned -- the general-purpose empty object.

The CS5App Class

data members

private static FilmDB F;
private static DirectorDB D;
These two data members are available in main and printMenu and the three file-handling methods, saveDB, readDB, and readFilmEntry. This means that the objects F and D do not have to be passed into these methods -- all of the methods in the CS5App class share these objects.

methods

public static void printMenu()
This method provides the following list of options (and a status line at the very beginning):

   0 Display All Directors
   1 Display All Films
   2 Display Films by Title
   3 Display Films by Director
   4 Display Films by Year
   5 Display Films by Rating
   6 Display Films by Review
   7 Add a New Film

   8 Save database to file
   9 Load database from file

  42 Quit

public static void saveDB(String fileNamePart)
This method will write the full contents of the object F of class FilmDB into the file named fileNamePart. The String, fileNamePart, should be converted to a full filename, as in the following:

  public static void saveDB(String fileNamePart)
  {
    String fullFileName = "../" + fileNamePart + ".txt";
    H.pl("Saving the database's contents to the file " + fullFileName);
    H.outputToFile(fullFileName);   // redirect the output to a file
    H.pl(F.getCapacity());          // print the capacity (length of the array)
    H.pl(F.getCount());             // print the count    (# of actual films)
    F.saveAllFilms();               // print all film data
    H.outputToConsole();            // redirect subsequent output to the console
  }

The above code is a working version of saveDB -- be sure to use it!

public static void readDB(String fileNamePart)
This method will replace the current contents of F with whatever is available in the file specified by fileNamePart. Note that the fileNamePart is in the directory above the source_code folder. It also has the extension .txt appended to it. Here is a working version of readDB, be sure to use it!:

  public static void readDB(String fileNamePart) 
  {
    String fullFileName = "../" + fileNamePart + ".txt";
    H.pl("Loading database contents from file " + fullFileName;
    H.inputFromFile(fullFileName);        // redirect input to come from the file
    int capacity = H.ni();                // reads in the capacity, an int
    F = new FilmDB(capacity);             // trashes the old F and creates a new one
    D = new DirectorDB(capacity);         // trashes the old D and creates a new one
    int count = H.ni();                   // reads in the count, an int
    for(int i = 0; i < count; i++)     // for each subsequent film...
    {
        readFilmEntry();                  // read that film's entry
    }
    H.inputFromConsole();                 // take subsequent input from the console
  }

public static void readFilmEntry()
This method is called above in readDB in order to take in all of the information in a film and handle both the film and the director appropriately. It is also called inside option #7 of the main menu in order to get the same information from the human user of the database. We will cover this method in some detail in class or in recitation. It should check to be sure the MPAA rating is one of the following Strings:
```
  G, PG, PG-13, R, NC-17, UR
```
and it should also check that the review score is between 0 and 10.0 inclusive. These checks will not disturb the process of reading from a file -- as long as the file contains only valid information!

Here is a more complete list of things that readFilmEntry needs to handle:
1. First the code must make sure there is still room to add the film in the FilmDB. If not, an error is printed and the method should return.
2. If there is room, the user is prompted for the title of the new film. Should this film already exist in the FilmDB (i.e. an exact match on the title is found), another message is printed and the method should return.
3. If the film is not already there, the user should be prompted for the director's last and first name (in that order). The findDirectorByName method should be used to check to see whether that director is already in D, the object of class DirectorDB. If that method returns null, a new object of type Director needs to be created and added to D. If that method does not return null, it returns the object of type Director which is already in the database D! As a result, that returned object should be used rather than creating a new one (which would be a duplicate).
4. Upon successfully finding (or creating) a Director object, the user then enters the rest of the film's information: year, MPAA rating (G, PG, PG-13, R, NC-17, UR), and review (0-10). Make sure these are valid entries!
5. With all of this information, a new Film object is created and added to the film database. The film also needs to be added to the director's personal film database! You can obtain this by calling getFilmDB() on the director object that you have either newly created or obtained from the findDirectorByName method.

public static void main(String[] args)
This method is described in detail below:

The main method drives the rest of the program and runs the user interface. This interface is similar in structure to those you have built in previous assignments.

The main method should begin with the lines

     F = new Film[100];     // creates a 100-film database by default
     D = new Director[100]; // creates a 100-director database by default

Then, it should present the user with the above menu of options and handle the option entered.

The handling of choices 0 through 6 are straightforward. The user is first prompted for an appropriate search value (options 0 and 1 don't even need a search value...). The appropriate method is called from either database F or D to print the desired information. Here are some details:

For option 2, the prompt should indicate that the program can search for a substring (i.e. the user need not enter the full title). To do this, you should use the indexOf method, which is described with some examples in the "helpful string methods" section below
In cases 5 and 6, main should check that the rating or review that is to be searched for is legitimate (i.e. between 0.0 and 10.0 or one of the 6 allowed MPAA ratings).
In handling case 3, the system prompts for the director's last and first name (in that order) and then searches the DirectorDB for that name. If a match is found, the contents of the director's FilmDB is printed; otherwise, a message reporting that the director was not found should be printed.
Handling case 7 simply involves calling the readFilmEntry method of the object F.

Helpful String Methods

The following Java-provided String methods will be useful in performing the String-based searches required in this assignment

toLowerCase: useful when making case-insensitive comparisons.
compareTo: useful when performing alphabetic sorting.
indexOf: useful for determining if one string is a substring of another.

Here are some examples of how each of these methods can be used:

String s = "Hamburger";
String t = "Urge";




+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-




s.indexOf(t)  -- returns the location of t within s or -1 if not there


if (s.indexOf(t) >= 0)
  H.out.println("s contains t");
else
  H.out.println("s does not contain t");


In this case, because "Urge" is capitalized, s.indexOf(t) would be -1
and the latter meddage would be printed out.



+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-




s.toLowerCase()  -- returns a string identical to s, but all lower case


if (s.toLowerCase().indexOf(t.toLowerCase()))
  H.out.println("s contains t (ignoring case)");
else
  H.out.println("s does not contain t (ignoring case)");


In this case, the former message would get printed.



+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-




s.compareTo(t)  -- returns 0 if s and t are identical strings
                   returns a number less than 0 if s is before t alphabetically
                   returns a number greater than 0 if s is after t alphabetically


if (s.compareTo(t) < 0)
  H.out.println("s is before t alphabetically");
else if (s.compareTo(t) > 0)
  H.out.println("s is after t alphabetically");
else 
  H.out.println("s and t are identical strings");


In this case, the first message would be printed out.


+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-




s.compareToIgnoreCase(t)  -- returns 0 if s and t are identical strings
                             returns a number less than 0 if s is before t (ignoring case)
                             returns a number greater than 0 if s is after t (ignoring case)


+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

Extra Credit Extra credit on this assignment involves replacing the methods that use for loops with ones that use recursion! We will look at a couple of these in class, and the same idea can be applied to the other methods that contain for loops... . Keep in mind that you don't have to use recursion at all -- this is simply if you'd like to try.

A Sample Run

The following text shows the output from a run of the program. Note that not every possible test is run here -- be sure to try out each option in your database!

Welcome the the CS 5 Movie Database.


There are 0 films in our database (max: 100)


Please choose from the following list:

   0 Display all directors
   1 Display all films
   2 Display all films by Title
   3 Display films by Director
   4 Display films by Year
   5 Display films by Rating (G, PG, ...)
   6 Display films by Review (0-10)
   7 Add a new film

   8 Save database to file
   9 Read database from file

  42 Quit

Which would you like? 9

Enter a file name: twofilms
Loading database contents from file ../twofilms.txt
100
2
Enter the title:                  Lord of the Rings: Return of
Enter the director's last name:   Jackson
Enter the director's first name:  Peter
Enter the movie's year:           2003
Enter the movie's MPAA rating:    PG-13
Enter a review score:             9.0


Enter the title:                  Gigli
Enter the director's last name:   Brest
Enter the director's first name:  Martin
Enter the movie's year:           2003
Enter the movie's MPAA rating:    R
Enter a review score:             2.2





There are 2 films in our database (max: 100)


Please choose from the following list:

   0 Display all directors
   1 Display all films
   2 Display all films by Title
   3 Display films by Director
   4 Display films by Year
   5 Display films by Rating (G, PG, ...)
   6 Display films by Review (0-10)
   7 Add a new film

   8 Save database to file
   9 Read database from file

  42 Quit

Which would you like? 0

Director #0 is Brest, Martin
Director #1 is Jackson, Peter



There are 2 films in our database (max: 100)


Please choose from the following list:

   0 Display all directors
   1 Display all films
   2 Display all films by Title
   3 Display films by Director
   4 Display films by Year
   5 Display films by Rating (G, PG, ...)
   6 Display films by Review (0-10)
   7 Add a new film

   8 Save database to file
   9 Read database from file

  42 Quit

Which would you like? 7

Enter the title:                  King Kong
Enter the director's last name:   Jackson
Enter the director's first name:  Peter
Enter the movie's year:           2005
Enter the movie's MPAA rating:    PG-13
Enter a review score:             6.0





There are 3 films in our database (max: 100)


Please choose from the following list:

   0 Display all directors
   1 Display all films
   2 Display all films by Title
   3 Display films by Director
   4 Display films by Year
   5 Display films by Rating (G, PG, ...)
   6 Display films by Review (0-10)
   7 Add a new film

   8 Save database to file
   9 Read database from file

  42 Quit

Which would you like? 1




Title:    Gigli
Director: Brest, Martin
Year:     2003
Rating:   R
Review:   2.2





Title:    King Kong
Director: Jackson, Peter
Year:     2005
Rating:   PG-13
Review:   6.0





Title:    Lord of the Rings: Return of the King
Director: Jackson, Peter
Year:     2003
Rating:   PG-13
Review:   9.0





There are 3 films in our database (max: 100)


Please choose from the following list:

   0 Display all directors
   1 Display all films
   2 Display all films by Title
   3 Display films by Director
   4 Display films by Year
   5 Display films by Rating (G, PG, ...)
   6 Display films by Review (0-10)
   7 Add a new film

   8 Save database to file
   9 Read database from file

  42 Quit

Which would you like? 2

Enter a titlepiece: king



Title:    King Kong
Director: Jackson, Peter
Year:     2005
Rating:   PG-13
Review:   6.0





Title:    Lord of the Rings: Return of the King
Director: Jackson, Peter
Year:     2003
Rating:   PG-13
Review:   9.0





There are 3 films in our database (max: 100)


Please choose from the following list:

   0 Display all directors
   1 Display all films
   2 Display all films by Title
   3 Display films by Director
   4 Display films by Year
   5 Display films by Rating (G, PG, ...)
   6 Display films by Review (0-10)
   7 Add a new film

   8 Save database to file
   9 Read database from file

  42 Quit

Which would you like? 3

Enter last name: Brest
Enter first name: Martin



Title:    Gigli
Director: Brest, Martin
Year:     2003
Rating:   R
Review:   2.2





There are 3 films in our database (max: 100)


Please choose from the following list:

   0 Display all directors
   1 Display all films
   2 Display all films by Title
   3 Display films by Director
   4 Display films by Year
   5 Display films by Rating (G, PG, ...)
   6 Display films by Review (0-10)
   7 Add a new film

   8 Save database to file
   9 Read database from file

  42 Quit

Which would you like? 8

Enter a file name: threefilms
Saving the database's contents to the file ../threefilms.txt



There are 3 films in our database (max: 100)


Please choose from the following list:

   0 Display all directors
   1 Display all films
   2 Display all films by Title
   3 Display films by Director
   4 Display films by Year
   5 Display films by Rating (G, PG, ...)
   6 Display films by Review (0-10)
   7 Add a new film

   8 Save database to file
   9 Read database from file

  42 Quit

Which would you like? 5

Enter a rating: 8.5



There are 3 films in our database (max: 100)


Please choose from the following list:

   0 Display all directors
   1 Display all films
   2 Display all films by Title
   3 Display films by Director
   4 Display films by Year
   5 Display films by Rating (G, PG, ...)
   6 Display films by Review (0-10)
   7 Add a new film

   8 Save database to file
   9 Read database from file

  42 Quit

Which would you like? 42



Until next time, the gallery is closed.