Class Dictionary

java.lang.Object

Dictionary

public class Dictionary
extends java.lang.Object

A dictionary manages a collection of known, correctly-spelled words. A dictionary is case insensitive and only stores "valid" words. 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) Tests whether the argued word is present in this 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)

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 store in this Dictionary

Throws:

java.lang.IllegalArgumentException - If the provided token scanner 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 from which to read words

Returns:

A Dictionary instance with words from the argued file

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 input file, it must only be counted once in the sum.

Returns:

Number of unique words in the dictionary

isWord

public boolean isWord(java.lang.String word)

Tests whether the argued word is present in this Dictionary. Note that strings containing nonword characters (such as spaces) will not be in the Dictionary. If the word is not in the Dictionary or if the word is null, this method returns false.

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

Calling this method must 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