org.jboss.forge.parser.java.util

Class Strings

java.lang.Object

org.jboss.forge.parser.java.util.Strings

public class Strings
extends Object

String utilities.

Author:

Lincoln Baxter, III

Constructor Summary

Constructors

Constructor and Description
Strings()

Method Summary

Methods

Modifier and Type	Method and Description
static boolean	areEqual(String left, String right)
static boolean	areEqualTrimmed(String left, String right)
static String	capitalize(String input) Capitalize the given String: "input" -> "Input"
static String	enquote(String value)
static int	getLevenshteinDistance(CharSequence s, CharSequence t) Find the Levenshtein distance between two Strings.
static int	getLevenshteinDistance(CharSequence s, CharSequence t, int threshold) Find the Levenshtein distance between two Strings if it's less than or equal to a given threshold.
static boolean	isNullOrEmpty(String string)
static boolean	isTrue(String value)
static String	join(Collection<?> collection, String delimiter)
static String	stripQuotes(String value)
static String	uncapitalize(String input)
static String	unquote(String value)

Methods inherited from class java.lang.Object

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

Constructor Detail

Strings

public Strings()

Method Detail

capitalize

public static String capitalize(String input)

Capitalize the given String: "input" -> "Input"

unquote

public static String unquote(String value)

enquote

public static String enquote(String value)

join

public static String join(Collection<?> collection,
          String delimiter)

isNullOrEmpty

public static boolean isNullOrEmpty(String string)

isTrue

public static boolean isTrue(String value)

areEqual

public static boolean areEqual(String left,
               String right)

areEqualTrimmed

public static boolean areEqualTrimmed(String left,
                      String right)

stripQuotes

public static String stripQuotes(String value)

uncapitalize

public static String uncapitalize(String input)

getLevenshteinDistance

public static int getLevenshteinDistance(CharSequence s,
                         CharSequence t)

Find the Levenshtein distance between two Strings.

This is the number of changes needed to change one String into another, where each change is a single character modification (deletion, insertion or substitution).

The previous implementation of the Levenshtein distance algorithm was from http://www.merriampark.com/ld.htm

Chas Emerick has written an implementation in Java, which avoids an OutOfMemoryError which can occur when my Java implementation is used with very large strings.
This implementation of the Levenshtein distance algorithm is from http://www.merriampark.com/ldjava.htm

 StringUtils.getLevenshteinDistance(null, *)             = IllegalArgumentException
 StringUtils.getLevenshteinDistance(*, null)             = IllegalArgumentException
 StringUtils.getLevenshteinDistance("","")               = 0
 StringUtils.getLevenshteinDistance("","a")              = 1
 StringUtils.getLevenshteinDistance("aaapppp", "")       = 7
 StringUtils.getLevenshteinDistance("frog", "fog")       = 1
 StringUtils.getLevenshteinDistance("fly", "ant")        = 3
 StringUtils.getLevenshteinDistance("elephant", "hippo") = 7
 StringUtils.getLevenshteinDistance("hippo", "elephant") = 7
 StringUtils.getLevenshteinDistance("hippo", "zzzzzzzz") = 8
 StringUtils.getLevenshteinDistance("hello", "hallo")    = 1
 

Parameters:

s - the first String, must not be null

t - the second String, must not be null

Returns:

result distance

Throws:

IllegalArgumentException - if either String input null

getLevenshteinDistance

public static int getLevenshteinDistance(CharSequence s,
                         CharSequence t,
                         int threshold)

Find the Levenshtein distance between two Strings if it's less than or equal to a given threshold.

This is the number of changes needed to change one String into another, where each change is a single character modification (deletion, insertion or substitution).

This implementation follows from Algorithms on Strings, Trees and Sequences by Dan Gusfield and Chas Emerick's implementation of the Levenshtein distance algorithm from http://www.merriampark.com/ld.htm

 StringUtils.getLevenshteinDistance(null, *, *)             = IllegalArgumentException
 StringUtils.getLevenshteinDistance(*, null, *)             = IllegalArgumentException
 StringUtils.getLevenshteinDistance(*, *, -1)               = IllegalArgumentException
 StringUtils.getLevenshteinDistance("","", 0)               = 0
 StringUtils.getLevenshteinDistance("aaapppp", "", 8)       = 7
 StringUtils.getLevenshteinDistance("aaapppp", "", 7)       = 7
 StringUtils.getLevenshteinDistance("aaapppp", "", 6))      = -1
 StringUtils.getLevenshteinDistance("elephant", "hippo", 7) = 7
 StringUtils.getLevenshteinDistance("elephant", "hippo", 6) = -1
 StringUtils.getLevenshteinDistance("hippo", "elephant", 7) = 7
 StringUtils.getLevenshteinDistance("hippo", "elephant", 6) = -1
 

Parameters:

s - the first String, must not be null

t - the second String, must not be null

threshold - the target threshold, must not be negative

Returns:

result distance, or -1 if the distance would be greater than the threshold

Throws:

IllegalArgumentException - if either String input null or negative threshold