org.apache.commons.lang
Class CharSet

java.lang.Object
  extended byorg.apache.commons.lang.CharSet
All Implemented Interfaces:
java.io.Serializable

public class CharSet
extends java.lang.Object
implements java.io.Serializable

A set of characters.

Instances are immutable, but instances of subclasses may not be.

Since:
1.0
Version:
$Id: CharSet.java 618884 2008-02-06 04:37:17Z bayard $
Author:
Stephen Colebourne, Phil Steitz, Pete Gieser, Gary Gregory
See Also:
Serialized Form

Field Summary
static CharSet ASCII_ALPHA
          A CharSet defining ASCII alphabetic characters "a-zA-Z".
static CharSet ASCII_ALPHA_LOWER
          A CharSet defining ASCII alphabetic characters "a-z".
static CharSet ASCII_ALPHA_UPPER
          A CharSet defining ASCII alphabetic characters "A-Z".
static CharSet ASCII_NUMERIC
          A CharSet defining ASCII alphabetic characters "0-9".
protected static java.util.Map COMMON
          A Map of the common cases used in the factory.
static CharSet EMPTY
          A CharSet defining no characters.
 
Constructor Summary
protected CharSet(java.lang.String setStr)
          Constructs a new CharSet using the set syntax.
protected CharSet(java.lang.String[] set)
          Constructs a new CharSet using the set syntax.
 
Method Summary
protected  void add(java.lang.String str)
          Add a set definition string to the CharSet.
 boolean contains(char ch)
          Does the CharSet contain the specified character ch.
 boolean equals(java.lang.Object obj)
          Compares two CharSet objects, returning true if they represent exactly the same set of characters defined in the same way.
 CharRange[] getCharRanges()
          Gets the internal set as an array of CharRange objects.
static CharSet getInstance(java.lang.String setStr)
          Factory method to create a new CharSet using a special syntax.
static CharSet getInstance(java.lang.String[] setStrs)
          Constructs a new CharSet using the set syntax.
 int hashCode()
          Gets a hashCode compatible with the equals method.
 java.lang.String toString()
          Gets a string representation of the set.
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

EMPTY

public static final CharSet EMPTY
A CharSet defining no characters.

Since:
2.0

ASCII_ALPHA

public static final CharSet ASCII_ALPHA
A CharSet defining ASCII alphabetic characters "a-zA-Z".

Since:
2.0

ASCII_ALPHA_LOWER

public static final CharSet ASCII_ALPHA_LOWER
A CharSet defining ASCII alphabetic characters "a-z".

Since:
2.0

ASCII_ALPHA_UPPER

public static final CharSet ASCII_ALPHA_UPPER
A CharSet defining ASCII alphabetic characters "A-Z".

Since:
2.0

ASCII_NUMERIC

public static final CharSet ASCII_NUMERIC
A CharSet defining ASCII alphabetic characters "0-9".

Since:
2.0

COMMON

protected static final java.util.Map COMMON
A Map of the common cases used in the factory. Subclasses can add more common patterns if desired.

Since:
2.0
Constructor Detail

CharSet

protected CharSet(java.lang.String setStr)

Constructs a new CharSet using the set syntax.

Parameters:
setStr - the String describing the set, may be null
Since:
2.0

CharSet

protected CharSet(java.lang.String[] set)

Constructs a new CharSet using the set syntax. Each string is merged in with the set.

Parameters:
set - Strings to merge into the initial set
Throws:
java.lang.NullPointerException - if set is null
Method Detail

getInstance

public static CharSet getInstance(java.lang.String setStr)

Factory method to create a new CharSet using a special syntax.

The matching order is:

  1. Negated multi character range, such as "^a-e"
  2. Ordinary multi character range, such as "a-e"
  3. Negated single character, such as "^a"
  4. Ordinary single character, such as "a"

Matching works left to right. Once a match is found the search starts again from the next character.

If the same range is defined twice using the same syntax, only one range will be kept. Thus, "a-ca-c" creates only one range of "a-c".

If the start and end of a range are in the wrong order, they are reversed. Thus "a-e" is the same as "e-a". As a result, "a-ee-a" would create only one range, as the "a-e" and "e-a" are the same.

The set of characters represented is the union of the specified ranges.

All CharSet objects returned by this method will be immutable.

Parameters:
setStr - the String describing the set, may be null
Returns:
a CharSet instance
Since:
2.0

getInstance

public static CharSet getInstance(java.lang.String[] setStrs)

Constructs a new CharSet using the set syntax. Each string is merged in with the set.

Parameters:
setStrs - Strings to merge into the initial set, may be null
Returns:
a CharSet instance
Since:
2.4

add

protected void add(java.lang.String str)

Add a set definition string to the CharSet.

Parameters:
str - set definition string

getCharRanges

public CharRange[] getCharRanges()

Gets the internal set as an array of CharRange objects.

Returns:
an array of immutable CharRange objects
Since:
2.0

contains

public boolean contains(char ch)

Does the CharSet contain the specified character ch.

Parameters:
ch - the character to check for
Returns:
true if the set contains the characters

equals

public boolean equals(java.lang.Object obj)

Compares two CharSet objects, returning true if they represent exactly the same set of characters defined in the same way.

The two sets abc and a-c are not equal according to this method.

Parameters:
obj - the object to compare to
Returns:
true if equal
Since:
2.0

hashCode

public int hashCode()

Gets a hashCode compatible with the equals method.

Returns:
a suitable hashCode
Since:
2.0

toString

public java.lang.String toString()

Gets a string representation of the set.

Returns:
string representation of the set


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