Class Dictionary

java.lang.Object

Dictionary

public class Dictionary
extends java.lang.Object

A dictionary manages a collection of known, correctly-spelled words. The dictionary is case insensitive and only stores "valid" word. A valid word is any sequence of letters (as determined by Character.isLetter) or apostrophes characters.

Constructor Summary

Constructors

Constructor and Description
Dictionary(TokenScanner ts) Constructs a dictionary from words provided by a TokenScanner.

Method Summary

Methods

Modifier and Type	Method and Description
int	getNumWords() Returns the number of unique words in this dictionary.
boolean	isWord(java.lang.String word) Test whether the input word is present in the Dictionary.
static Dictionary	make(java.lang.String filename) Constructs a dictionary from words from a file.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Dictionary

public Dictionary(TokenScanner ts)
           throws java.io.IOException

Constructs a dictionary from words provided by a TokenScanner.

A word is any sequence of letters (see Character.isLetter) or apostrophe characters. All non-word tokens provided by the TokenScanner should be ignored.

Parameters:

ts - sequence of words to use as a dictionary

Throws:

java.io.IOException - if error while reading

java.lang.IllegalArgumentException - if the provided reader is null

Method Detail

make

public static Dictionary make(java.lang.String filename)
                       throws java.io.IOException

Constructs a dictionary from words from a file.

Parameters:

filename - location of file to read words from

Throws:

java.io.FileNotFoundException - if the file does not exist

java.io.IOException - if error while reading

getNumWords

public int getNumWords()

Returns the number of unique words in this dictionary. This count is case insensitive: if both "DOGS" and "dogs" appeared in the file, it should only be counted once in the returned sum.

Returns:

number of unique words in the dictionary

isWord

public boolean isWord(java.lang.String word)

Test whether the input word is present in the Dictionary.

This check should be case insensitive. For example, if the Dictionary contains "dog" or "dOg" then isWord("DOG") should return true.

The argument to this method should only contain letters or apostrophe characters. The empty string, or strings containing only whitespace characters, are not in the dictionary. If the argument is null, the method returns false.

Calling this method should not re-open or re-read the source file.

Parameters:

word - a string token to check. Assume any leading or trailing whitespace has already been removed.

Returns:

whether the word is in the dictionary