CS 151 Fall 2007 Lab 12

Reading Input, Writing Output, Handling Exceptions

 

The goals for this lab are to get more practice reading from and writing to files and handling errors.

 

  1. Open BlueJ either by selecting it from the Dock or navigating to it in the Applications folder and double clicking it.

  2. Mount your network directory/folder so that you can access the lab after you leave Olin 323.  Go to the Finder and from the Go menu select Connect to Server....  Type afp://fileserver1 or choose it from the list of selections and select the Personal volume when prompted.

  3. From the Project menu select New Project.  Select your computer from the drop down menu.  Then scroll down and open the Volumes folder and then the Personal folder inside it.  Scroll down the long list of folders until your find yours.  Create a project called "Lab12" in your personal network folder.

  4. (Exercise P11.1 from your book) Write a program that reads a specified file and prints out the number of lines, words, and characters in it.  Call the class FileStats or some other meaningful name.  Assume that the user specifies the file name when calling the main method of your class.  This means you can find it in the main method's parameter args (a String array).  Don't forget to import the Scanner class from the java.util package and FileReader and whatever else you need from the java.io package (java.io.*).  For starters, just throw the checked FileNotFound exception that might occur when you try to open the file.  Recall that for a given String, calling its split() method with a blank space, " ", as a parameter returns an array of words.  Create your own file(s) for testing.

  5. Modify your program so that if args doesn't contain a file name or the one it contains can't be found, the user is prompted for a filename. If the file name the user enters on the command line can't be found, keep prompting the user until he or she enters a valid file name.  Recall that to get terminal input from the user you need to create a Scanner object connected to System.in.  First use an if clause on the length of args to test whether or not it contains a name.  Then, instead try catching the ArrayIndexOutOfBoundsException thrown when access args[0] when args is empty (not null, just empty).

 

  1. (Based on Exercise P11.14 from your book) Time permitting, write another program that reads a list of PlayingCards from a file and creates a BlackJackDeck containing those cards.  The input file has the format:

    suit1           rank1           value1
    suit2           rank2           value2
    ...

    w    here suit1 and rank1 are strings and value1 is an integer.  Feel free to use your Project 5 PlayingCard and BlackJackDeck classes or the hyperlinked versions from my solution.  This should give you some ideas for the restore method for your project.  If you don't get to this in lab, spend your time on your project instead.

 

  1. Add a method

    void read(Scanner input) throws IOException

    to the PlayingCard class.  Note that essentially all it does is read in the suit, rank, and value for the card from which it's called.  Throw an exception if the current line is not properly formatted. 

 

  1. Add to the BlackJackDeck class a method

    static ArrayList<PlayingCard> readFile(String filename) throws IOException

    It should create cards, read their information from the file using read() and add them to the ArrayList.  Also add another BlackJackDeck constructor that takes the name of a file as a parameter.  It should call readFile() and construct a deck with the ArrayList that readFile() returns.  What should the constructor do with any exceptions that readFile() might throw?