Class SwapCorrector

java.lang.Object

Corrector

SwapCorrector

public class SwapCorrector
extends Corrector

A Corrector whose spelling suggestions come from "swapped letter" typos.

A common misspelling is accidentally swapping two adjacent letters, e.g. "with" -> "wiht". This Corrector is given a Dictionary of valid words and proposes corrections that are precisely one "swap" away from the incorrect word.

For example, if the incorrect word is "haet", then this Corrector might suggest "heat" and "hate", provided that both of these words occur in the dictionary.

Only swaps between adjacent letters are considered by this corrector.

Constructor Summary

Constructors

Constructor and Description
SwapCorrector(Dictionary dict) Constructs a SwapCorrector using the argued Dictionary.

Method Summary

Methods

Modifier and Type	Method and Description
java.util.Set<java.lang.String>	getCorrections(java.lang.String wrong) Suggests as corrections any words in the Dictionary (provided when this object is constructed) that are one swap away from the input word.

Methods inherited from class Corrector

matchCase

Methods inherited from class java.lang.Object

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

Constructor Detail

SwapCorrector

public SwapCorrector(Dictionary dict)

Constructs a SwapCorrector using the argued Dictionary.

Parameters:

dict - The reference dictionary to use to look for corrections arising from letter swaps

Throws:

java.lang.IllegalArgumentException - If the argued Dictionary is null

Method Detail

getCorrections

public java.util.Set<java.lang.String> getCorrections(java.lang.String wrong)

Suggests as corrections any words in the Dictionary (provided when this object is constructed) that are one swap away from the input word. A swap is defined as two adjacent letters exchanging positions.

For example, if the Dictionary contains the words "heat" and "hate", then both should be returned if the input wrong word is "haet".

If the provided word is already spelled correctly, then the empty set should be returned. The corrections should match the case of the input; the matchCase method is helpful here. For any input that is *not* a valid word, throw an IllegalArgumentException. A valid word is any sequence of letters (as determined by Character.isLetter) or apostrophes characters.

Specified by:

getCorrections in class Corrector

Parameters:

wrong - The misspelled word

Returns:

A (potentially empty) set of proposed corrections

Throws:

java.lang.IllegalArgumentException - If the input is not a valid word (i.e. not composed of only letters and/or apostrophes)