CSCI 2341 A06

A06

Due Date: Thursday, March 5
File(s) to be submitted: TextItems.java
Sample Output: SampleOutput.html
Starter Files:

Creating the TextItems Class (File I/O, Exceptions, Lists)

Summary

Implement the TextItems class. This class is designed to show text one page at a time. It consists of a constructor and a method to display an item. The text is drawn from a file when a TextItems object is constructed.
In TextItems create a private class Item that holds the name and contents of the text item.
Use List objects to hold the contents of each Item and all the Items of the TextItem.

Details

The TextItems class encapsulates an object that holds and displays pre-formatted text. Each block of text has a name that the client uses to request the block, and it may include "pauses" where the computer will stop and wait for the user to press the enter key.

The constructor takes two arguments: a file name and a Scanner. For example:

TextItems ti = new TextItems("MiniItems.txt", KBD);

The Items come from the named file. The Scanner's use is described below.

The text in the named file is in this format:

The first line is the title of the text item.
The following lines are the text of the item.
After the last line of the item's text, there is a line of 80 hyphens, signaling the end of the item. (This must have exactly 80 hyphens; otherwise it's just another line in the file.)
Items repeat in the same pattern until the end of the file.

For example, the file MiniItems.txt is as follows:

First Item
First line of first item
Second line of first item
--------------------------------------------------------------------------------
Second Item
First line of second item

Third line of second item
--------------------------------------------------------------------------------

It consists of two items, one named "First Item" and the other named "Second Item". The first item has two lines, while the second has three (the middle line being blank). When the client asks to display "First Item"

ti.displayItem("First Item");

the screen should show

First line of first item Second line of first item

When the client asks for the "Second Item" the screen would show

First line of second item Third line of second item

Some items will contain a line of 80 at signs (@). Those lines are not to be printed, but instead signify that the print-out should pause (with a brief message, such as "...press enter...") and wait for the user to press the enter key.

Note: this is what the Scanner argument to the constructor is for. That is the Scanner you need to listen on for the user to press enter.

(The line must have exactly 80 at signs or else it's just another line to be printed.) For full credit that's just what your code should do.

Further Requirements

You must use List instance variables in your implementation. Use of other data structures/data types will be penalized.
Use a private inner class to hold the data for a single text item.
If the file requested by the client can't be found (or read from), then the constructor should throw an IllegalArgumentException with the file name as its message.
If the file ends unexpectedly, the constructor should throw an InputMismatchException with the file name as message.
If the client should ask for a text item that doesn't exist, displayItem should throw a NoSuchElementException with the (requested) item name as its message.

Hints

Remember that NetBeans looks for files starting in the project folder (not the src folder). Be sure to place your files there and make sure they have the right names (remember that Windows often lies to you about the names of files).
Work in small steps! Recompile and run the test program after each step. Make sure it's working properly before you go on to the next step.
1. Create stubs for the constructor and method.
2. Add code to the constructor to open the file (or deal with failure).
3. Add code to "scan" the file -- read in each item and print out its title without saving that information anywhere. Get it to scan one item then add the outer loop to read multiple items. (Make sure that it prints out all the titles from each file.)
4. Add code to fill in the text items' lines.
5. Add code to deal with truncated data files (it's another catch block for the try-catch block you should already have).
6. Add code to print out an item -- not worrying about the pauses.
7. Add code to pause at the appropriate times.
8. Do a thorough testing, including making sure that BOTH "fails" at the end do what they're supposed to.
Checking for item end/pause You can create variables to hold Strings with 80 hyphens and exclamation marks, and compare the Strings you read to them, but there is an easier way. It's possible to ask a String if it matches a pattern, and one pattern you can specify is a number of repetitions of a single character. For example,
```
line.matches("%{20}")
```
return true if (and only if) line is a String of exactly 20% signs. Similarly,
```
str.matches("E{50}K!")
```
return true if (and only if) str is a String of exactly 50 Es followed by a K and an exclamation point. From these I trust you can figure out how to ask if a String is exactly 80 hyphens/at signs long.

SUBMIT / Check