Spelling Checker
Note: Projects are to be completed by each student individually (not by groups of students).A spelling
checker reads the words in a document and outputs a list of misspelled words.
For each misspelled word, the program outputs the word followed by a list of
the line numbers where the word is found in the document.
The program decides
which words are misspelled by using a dictionary of correct words. The program
searches the dictionary for each word in the document. If a word from the
document cannot be found in the dictionary, the word is added to the list of
misspelled words.
After you read this specification, you might want to check out the TIPS page.
Project Files
The following files are required to complete the project. You should download these files with a web browser. You are not allowed to modify these files in any way except for implementing methods that were intentionally left empty. Specifically, interface definitions may not be modified, and all code must remain in the cs235.spell package.
spell.zip : Contains all the files listed below.
NOTE: When
downloading these files, use SHIFT+click (or right-click, Save As...) to
download a literal copy of these text files. Do not cut-and-paste these files,
or you may have problems with the TestDriver.
Dictionary File Format
The spelling
checker reads one or more dictionaries of correct words. Each dictionary is a
text file that contains a list of words, one word per line as shown in this
example.
many
this
dogs
fly
think
Loading
dictionaries is additive; if you load 200 dictionaries, all of the (unique)
words in all 200 dictionaries will now be in the set of correct words. Loading
a new dictionary into the spelling checker should not remove any of the words
that were previously in the set of correct words (although new words that are
duplicates of old words need not be added).
Document Files
The documents to be spell checked are just regular text files (i.e., sequences of characters). The spelling checker reads in the file to be spell checked and extracts all of the words from the file. Each word in the file is checked against the words in the currently loaded dictionaries in order to detect misspelled words. If a word is not found in the currently loaded dictionaries, it is considered to be misspelled. A document file might contain English prose, or it could just be a list of words. The program does the same thing in either case: 1) extracts the words in the file and 2) checks to see if they're in the dictionary.
How does the program find the words in the document file? Words are defined as sequences of letters that are separated by characters that are not letters. The characters that you need to check for are numbers, white space (spaces, tabs, new lines, etc.), periods, commas, colons, semi-colons, parentheses, apostrophes, hyphens, equals, pluses, percents, slashes, quotes, asterisks, square braces, curly braces, less than, greater than, question marks, exclamation marks, ampersands, vertical bars and underscores. (Look here for a literal list of these non-letter characters/delimiters).
Output Format
The output of
the spelling checker is a sorted list of words, one word per line. Use a \n
character to indicate a new line. Each word is lower case and followed by a colon and a
comma-separated list of line numbers where the word is found in the document.
Make sure to remember the space after the comma.
short: 1, 2
this: 1
very: 2
Requirement #1: Write a Class that Implements the cs235.spell.SpellingChecker Interface
The file SpellingChecker.java defines an interface named SpellingChecker. SpellingChecker has two methods. The first method is loadDictionary which loads a dictionary file into the
spelling checker. More than one dictionary can be loaded into the spelling
checker dictionary. The spelling checker uses the union of all the dictionaries
that are loaded. The second method is checkDocument which reads the words from a document
and checks them against the loaded dictionaries. When you look for a word in
the dictionary, the comparison should not be case-sensitive.
You are
required to write a class that implements the SpellingChecker interface. You might name your class
something like SpellingCheckerImpl.
Put your implementation class in the cs235.spell package.
Your spelling
checker implementation could use a number of supporting classes such as Dictionary, Document, and Index.
You could also use a number of classes from the Java class library such as Set, Map, and List.
(NOTE: Set, Map, and List are
interfaces. You should use one of the classes that implements them.) A Dictionary object could contain a Set of words. A Document object could have the ability to parse a
document into individual words. An Index
object could contain a Map
of key/value pairs where the key is a word and the value is a List of line numbers. The exact
implementation is left up to you.
Requirement #2: Implement the Method in the cs235.spell.CheckerFactory class
The file CheckerFactory.java contains a class named CheckerFactory. This class has one method named createSpellingChecker. You must implement this method so that
it creates a new instance of your spelling checker class and returns it.
Requirement #3: Test Your Code
You are
responsible for testing your code and making sure that it works. To assist your testing effort (and to make it
more fun), we have provided a program with a graphical user interface that
allows you to interactively load dictionaries and documents, and run your
spelling checker to highlight the misspelled words. This program is found in SpellCheckGUI.java.
A test driver
program is also provided to help you test your code. The test driver is found in TestDriver.java. The
files words.txt, dict.txt, test.txt, short.txt, empty.txt, one-word.txt, bill-of-rights.txt, emancipation-proclamation.txt, gettysburg-address.txt, monroe-doctrine.txt, preamble.txt must be in the current directory when you
run the test driver.
Using the
test driver should help you get your code working and help you determine when
it is ready to be passed off. In fact, you are required to make your code work
with the test driver before passing it off. When you pass off your program, a program similar (but not identical) to the test driver will be used to test your code.
Requirement #4: Pass Off Your Project with a TA
Go through the submission process and then meet with a TA for a pass off interview.