Class CharMatcher
char
value, just as Predicate
does
for any Object
. Also offers basic text processing methods based on this function.
Implementations are strongly encouraged to be side-effect-free and immutable.
Throughout the documentation of this class, the phrase "matching character" is used to mean
"any char
value c
for which this.matches(c)
returns true
".
Warning: This class deals only with char
values; it does not understand
supplementary Unicode code points in the range 0x10000
to 0x10FFFF
. Such logical
characters are encoded into a String
using surrogate pairs, and a CharMatcher
treats these just as two separate characters.
Example usages:
String trimmed =whitespace()
.trimFrom
(userInput); if (ascii()
.matchesAllOf
(s)) { ... }
See the Guava User Guide article on CharMatcher
.
- Since:
- 1.0
-
Field Summary
FieldsModifier and TypeFieldDescriptionstatic final CharMatcher
Deprecated.static final CharMatcher
Deprecated.Useascii()
instead.static final CharMatcher
Deprecated.UsebreakingWhitespace()
instead.static final CharMatcher
Deprecated.Usedigit()
instead.static final CharMatcher
Deprecated.Useinvisible()
instead.static final CharMatcher
Deprecated.UsejavaDigit()
instead.static final CharMatcher
Deprecated.UsejavaIsoControl()
instead.static final CharMatcher
Deprecated.UsejavaLetter()
instead.static final CharMatcher
Deprecated.UsejavaLetterOrDigit()
instead.static final CharMatcher
Deprecated.UsejavaLowerCase()
instead.static final CharMatcher
Deprecated.UsejavaUpperCase()
instead.static final CharMatcher
Deprecated.Usenone()
instead.static final CharMatcher
Deprecated.UsesingleWidth()
instead.static final CharMatcher
Deprecated.Usewhitespace()
instead. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionand
(CharMatcher other) Returns a matcher that matches any character matched by both this matcher andother
.static CharMatcher
any()
Matches any character.static CharMatcher
anyOf
(CharSequence sequence) Returns achar
matcher that matches any character present in the given character sequence.boolean
Deprecated.Provided only to satisfy thePredicate
interface; usematches(char)
instead.static CharMatcher
ascii()
Determines whether a character is ASCII, meaning that its code point is less than 128.static CharMatcher
Determines whether a character is a breaking whitespace (that is, a whitespace which can be interpreted as a break between words for formatting purposes).collapseFrom
(CharSequence sequence, char replacement) Returns a string copy of the input character sequence, with each group of consecutive characters that match this matcher replaced by a single replacement character.int
countIn
(CharSequence sequence) Returns the number of matching characters found in a character sequence.static CharMatcher
digit()
Determines whether a character is a digit according to Unicode.static CharMatcher
forPredicate
(Predicate<? super Character> predicate) Returns a matcher with identical behavior to the givenCharacter
-based predicate, but which operates on primitivechar
instances instead.int
indexIn
(CharSequence sequence) Returns the index of the first matching character in a character sequence, or-1
if no matching character is present.int
indexIn
(CharSequence sequence, int start) Returns the index of the first matching character in a character sequence, starting from a given position, or-1
if no character matches after that position.static CharMatcher
inRange
(char startInclusive, char endInclusive) Returns achar
matcher that matches any character in a given range (both endpoints are inclusive).static CharMatcher
Determines whether a character is invisible; that is, if its Unicode category is any of SPACE_SEPARATOR, LINE_SEPARATOR, PARAGRAPH_SEPARATOR, CONTROL, FORMAT, SURROGATE, and PRIVATE_USE according to ICU4J.static CharMatcher
is
(char match) Returns achar
matcher that matches only one specified character.static CharMatcher
isNot
(char match) Returns achar
matcher that matches any character except the one specified.static CharMatcher
Determines whether a character is a digit according to Java's definition.static CharMatcher
Determines whether a character is an ISO control character as specified byCharacter.isISOControl(char)
.static CharMatcher
Determines whether a character is a letter according to Java's definition.static CharMatcher
Determines whether a character is a letter or digit according to Java's definition.static CharMatcher
Determines whether a character is lower case according to Java's definition.static CharMatcher
Determines whether a character is upper case according to Java's definition.int
lastIndexIn
(CharSequence sequence) Returns the index of the last matching character in a character sequence, or-1
if no matching character is present.abstract boolean
matches
(char c) Determines a true or false value for the given character.boolean
matchesAllOf
(CharSequence sequence) Returnstrue
if a character sequence contains only matching characters.boolean
matchesAnyOf
(CharSequence sequence) Returnstrue
if a character sequence contains at least one matching character.boolean
matchesNoneOf
(CharSequence sequence) Returnstrue
if a character sequence contains no matching characters.negate()
Returns a matcher that matches any character not matched by this matcher.static CharMatcher
none()
Matches no characters.static CharMatcher
noneOf
(CharSequence sequence) Returns achar
matcher that matches any character not present in the given character sequence.or
(CharMatcher other) Returns a matcher that matches any character matched by either this matcher orother
.Returns achar
matcher functionally equivalent to this one, but which may be faster to query than the original; your mileage may vary.removeFrom
(CharSequence sequence) Returns a string containing all non-matching characters of a character sequence, in order.replaceFrom
(CharSequence sequence, char replacement) Returns a string copy of the input character sequence, with each character that matches this matcher replaced by a given replacement character.replaceFrom
(CharSequence sequence, CharSequence replacement) Returns a string copy of the input character sequence, with each character that matches this matcher replaced by a given replacement sequence.retainFrom
(CharSequence sequence) Returns a string containing all matching characters of a character sequence, in order.static CharMatcher
Determines whether a character is single-width (not double-width).toString()
Returns a string representation of thisCharMatcher
, such asCharMatcher.or(WHITESPACE, JAVA_DIGIT)
.trimAndCollapseFrom
(CharSequence sequence, char replacement) Collapses groups of matching characters exactly ascollapseFrom(java.lang.CharSequence, char)
does, except that groups of matching characters at the start or end of the sequence are removed without replacement.trimFrom
(CharSequence sequence) Returns a substring of the input character sequence that omits all characters this matcher matches from the beginning and from the end of the string.trimLeadingFrom
(CharSequence sequence) Returns a substring of the input character sequence that omits all characters this matcher matches from the beginning of the string.trimTrailingFrom
(CharSequence sequence) Returns a substring of the input character sequence that omits all characters this matcher matches from the end of the string.static CharMatcher
Determines whether a character is whitespace according to the latest Unicode standard, as illustrated here.
-
Field Details
-
WHITESPACE
Deprecated.Usewhitespace()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is whitespace according to the latest Unicode standard, as illustrated here. This is not the same definition used by other Java APIs. (See a comparison of several definitions of "whitespace".)Note: as the Unicode definition evolves, we will modify this constant to keep it up to date.
-
BREAKING_WHITESPACE
Deprecated.UsebreakingWhitespace()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is a breaking whitespace (that is, a whitespace which can be interpreted as a break between words for formatting purposes). Seewhitespace()
for a discussion of that term.- Since:
- 2.0
-
ASCII
Deprecated.Useascii()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is ASCII, meaning that its code point is less than 128. -
DIGIT
Deprecated.Usedigit()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is a digit according to Unicode. If you only care to match ASCII digits, you can useinRange('0', '9')
. -
JAVA_DIGIT
Deprecated.UsejavaDigit()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is a digit according to Java's definition. If you only care to match ASCII digits, you can useinRange('0', '9')
. -
JAVA_LETTER
Deprecated.UsejavaLetter()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is a letter according to Java's definition. If you only care to match letters of the Latin alphabet, you can useinRange('a', 'z').or(inRange('A', 'Z'))
. -
JAVA_LETTER_OR_DIGIT
Deprecated.UsejavaLetterOrDigit()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is a letter or digit according to Java's definition. -
JAVA_UPPER_CASE
Deprecated.UsejavaUpperCase()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is upper case according to Java's definition. -
JAVA_LOWER_CASE
Deprecated.UsejavaLowerCase()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is lower case according to Java's definition. -
JAVA_ISO_CONTROL
Deprecated.UsejavaIsoControl()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is an ISO control character as specified byCharacter.isISOControl(char)
. -
INVISIBLE
Deprecated.Useinvisible()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is invisible; that is, if its Unicode category is any of SPACE_SEPARATOR, LINE_SEPARATOR, PARAGRAPH_SEPARATOR, CONTROL, FORMAT, SURROGATE, and PRIVATE_USE according to ICU4J. -
SINGLE_WIDTH
Deprecated.UsesingleWidth()
instead. This constant is scheduled to be removed in June 2018.Determines whether a character is single-width (not double-width). When in doubt, this matcher errs on the side of returningfalse
(that is, it tends to assume a character is double-width).Note: as the reference file evolves, we will modify this constant to keep it up to date.
-
ANY
Deprecated.Useany()
instead. This constant is scheduled to be removed in June 2018.Matches any character. -
NONE
Deprecated.Usenone()
instead. This constant is scheduled to be removed in June 2018.Matches no characters.
-
-
Constructor Details
-
CharMatcher
protected CharMatcher()Constructor for use by subclasses. When subclassing, you may want to overridetoString()
to provide a useful description.
-
-
Method Details
-
any
Matches any character.- Since:
- 19.0 (since 1.0 as constant
ANY
)
-
none
Matches no characters.- Since:
- 19.0 (since 1.0 as constant
NONE
)
-
whitespace
Determines whether a character is whitespace according to the latest Unicode standard, as illustrated here. This is not the same definition used by other Java APIs. (See a comparison of several definitions of "whitespace".)Note: as the Unicode definition evolves, we will modify this matcher to keep it up to date.
- Since:
- 19.0 (since 1.0 as constant
WHITESPACE
)
-
breakingWhitespace
Determines whether a character is a breaking whitespace (that is, a whitespace which can be interpreted as a break between words for formatting purposes). Seewhitespace()
for a discussion of that term.- Since:
- 19.0 (since 2.0 as constant
BREAKING_WHITESPACE
)
-
ascii
Determines whether a character is ASCII, meaning that its code point is less than 128.- Since:
- 19.0 (since 1.0 as constant
ASCII
)
-
digit
Determines whether a character is a digit according to Unicode. If you only care to match ASCII digits, you can useinRange('0', '9')
.- Since:
- 19.0 (since 1.0 as constant
DIGIT
)
-
javaDigit
Determines whether a character is a digit according to Java's definition. If you only care to match ASCII digits, you can useinRange('0', '9')
.- Since:
- 19.0 (since 1.0 as constant
JAVA_DIGIT
)
-
javaLetter
Determines whether a character is a letter according to Java's definition. If you only care to match letters of the Latin alphabet, you can useinRange('a', 'z').or(inRange('A', 'Z'))
.- Since:
- 19.0 (since 1.0 as constant
JAVA_LETTER
)
-
javaLetterOrDigit
Determines whether a character is a letter or digit according to Java's definition.- Since:
- 19.0 (since 1.0 as constant
JAVA_LETTER_OR_DIGIT
).
-
javaUpperCase
Determines whether a character is upper case according to Java's definition.- Since:
- 19.0 (since 1.0 as constant
JAVA_UPPER_CASE
)
-
javaLowerCase
Determines whether a character is lower case according to Java's definition.- Since:
- 19.0 (since 1.0 as constant
JAVA_LOWER_CASE
)
-
javaIsoControl
Determines whether a character is an ISO control character as specified byCharacter.isISOControl(char)
.- Since:
- 19.0 (since 1.0 as constant
JAVA_ISO_CONTROL
)
-
invisible
Determines whether a character is invisible; that is, if its Unicode category is any of SPACE_SEPARATOR, LINE_SEPARATOR, PARAGRAPH_SEPARATOR, CONTROL, FORMAT, SURROGATE, and PRIVATE_USE according to ICU4J.- Since:
- 19.0 (since 1.0 as constant
INVISIBLE
)
-
singleWidth
Determines whether a character is single-width (not double-width). When in doubt, this matcher errs on the side of returningfalse
(that is, it tends to assume a character is double-width).Note: as the reference file evolves, we will modify this matcher to keep it up to date.
- Since:
- 19.0 (since 1.0 as constant
SINGLE_WIDTH
)
-
is
Returns achar
matcher that matches only one specified character. -
isNot
Returns achar
matcher that matches any character except the one specified.To negate another
CharMatcher
, usenegate()
. -
anyOf
Returns achar
matcher that matches any character present in the given character sequence. -
noneOf
Returns achar
matcher that matches any character not present in the given character sequence. -
inRange
Returns achar
matcher that matches any character in a given range (both endpoints are inclusive). For example, to match any lowercase letter of the English alphabet, useCharMatcher.inRange('a', 'z')
.- Throws:
IllegalArgumentException
- ifendInclusive < startInclusive
-
forPredicate
Returns a matcher with identical behavior to the givenCharacter
-based predicate, but which operates on primitivechar
instances instead. -
matches
public abstract boolean matches(char c) Determines a true or false value for the given character. -
negate
Returns a matcher that matches any character not matched by this matcher. -
and
Returns a matcher that matches any character matched by both this matcher andother
. -
or
Returns a matcher that matches any character matched by either this matcher orother
. -
precomputed
Returns achar
matcher functionally equivalent to this one, but which may be faster to query than the original; your mileage may vary. Precomputation takes time and is likely to be worthwhile only if the precomputed matcher is queried many thousands of times.This method has no effect (returns
this
) when called in GWT: it's unclear whether a precomputed matcher is faster, but it certainly consumes more memory, which doesn't seem like a worthwhile tradeoff in a browser. -
matchesAnyOf
Returnstrue
if a character sequence contains at least one matching character. Equivalent to!matchesNoneOf(sequence)
.The default implementation iterates over the sequence, invoking
matches(char)
for each character, until this returnstrue
or the end is reached.- Parameters:
sequence
- the character sequence to examine, possibly empty- Returns:
true
if this matcher matches at least one character in the sequence- Since:
- 8.0
-
matchesAllOf
Returnstrue
if a character sequence contains only matching characters.The default implementation iterates over the sequence, invoking
matches(char)
for each character, until this returnsfalse
or the end is reached.- Parameters:
sequence
- the character sequence to examine, possibly empty- Returns:
true
if this matcher matches every character in the sequence, including when the sequence is empty
-
matchesNoneOf
Returnstrue
if a character sequence contains no matching characters. Equivalent to!matchesAnyOf(sequence)
.The default implementation iterates over the sequence, invoking
matches(char)
for each character, until this returnstrue
or the end is reached.- Parameters:
sequence
- the character sequence to examine, possibly empty- Returns:
true
if this matcher matches no characters in the sequence, including when the sequence is empty
-
indexIn
Returns the index of the first matching character in a character sequence, or-1
if no matching character is present.The default implementation iterates over the sequence in forward order calling
matches(char)
for each character.- Parameters:
sequence
- the character sequence to examine from the beginning- Returns:
- an index, or
-1
if no character matches
-
indexIn
Returns the index of the first matching character in a character sequence, starting from a given position, or-1
if no character matches after that position.The default implementation iterates over the sequence in forward order, beginning at
start
, callingmatches(char)
for each character.- Parameters:
sequence
- the character sequence to examinestart
- the first index to examine; must be nonnegative and no greater thansequence.length()
- Returns:
- the index of the first matching character, guaranteed to be no less than
start
, or-1
if no character matches - Throws:
IndexOutOfBoundsException
- if start is negative or greater thansequence.length()
-
lastIndexIn
Returns the index of the last matching character in a character sequence, or-1
if no matching character is present.The default implementation iterates over the sequence in reverse order calling
matches(char)
for each character.- Parameters:
sequence
- the character sequence to examine from the end- Returns:
- an index, or
-1
if no character matches
-
countIn
Returns the number of matching characters found in a character sequence. -
removeFrom
Returns a string containing all non-matching characters of a character sequence, in order. For example:CharMatcher.is('a').removeFrom("bazaar")
"bzr"
. -
retainFrom
Returns a string containing all matching characters of a character sequence, in order. For example:CharMatcher.is('a').retainFrom("bazaar")
"aaa"
. -
replaceFrom
Returns a string copy of the input character sequence, with each character that matches this matcher replaced by a given replacement character. For example:CharMatcher.is('a').replaceFrom("radar", 'o')
"rodor"
.The default implementation uses
indexIn(CharSequence)
to find the first matching character, then iterates the remainder of the sequence callingmatches(char)
for each character.- Parameters:
sequence
- the character sequence to replace matching characters inreplacement
- the character to append to the result string in place of each matching character insequence
- Returns:
- the new string
-
replaceFrom
Returns a string copy of the input character sequence, with each character that matches this matcher replaced by a given replacement sequence. For example:CharMatcher.is('a').replaceFrom("yaha", "oo")
"yoohoo"
.Note: If the replacement is a fixed string with only one character, you are better off calling
replaceFrom(CharSequence, char)
directly.- Parameters:
sequence
- the character sequence to replace matching characters inreplacement
- the characters to append to the result string in place of each matching character insequence
- Returns:
- the new string
-
trimFrom
Returns a substring of the input character sequence that omits all characters this matcher matches from the beginning and from the end of the string. For example:CharMatcher.anyOf("ab").trimFrom("abacatbab")
"cat"
.Note that:
CharMatcher.inRange('\0', ' ').trimFrom(str)
String.trim()
. -
trimLeadingFrom
Returns a substring of the input character sequence that omits all characters this matcher matches from the beginning of the string. For example:CharMatcher.anyOf("ab").trimLeadingFrom("abacatbab")
"catbab"
. -
trimTrailingFrom
Returns a substring of the input character sequence that omits all characters this matcher matches from the end of the string. For example:CharMatcher.anyOf("ab").trimTrailingFrom("abacatbab")
"abacat"
. -
collapseFrom
Returns a string copy of the input character sequence, with each group of consecutive characters that match this matcher replaced by a single replacement character. For example:CharMatcher.anyOf("eko").collapseFrom("bookkeeper", '-')
"b-p-r"
.The default implementation uses
indexIn(CharSequence)
to find the first matching character, then iterates the remainder of the sequence callingmatches(char)
for each character.- Parameters:
sequence
- the character sequence to replace matching groups of characters inreplacement
- the character to append to the result string in place of each group of matching characters insequence
- Returns:
- the new string
-
trimAndCollapseFrom
Collapses groups of matching characters exactly ascollapseFrom(java.lang.CharSequence, char)
does, except that groups of matching characters at the start or end of the sequence are removed without replacement. -
apply
Deprecated.Provided only to satisfy thePredicate
interface; usematches(char)
instead.Description copied from interface:Predicate
Returns the result of applying this predicate toinput
(Java 8 users, see notes in the class documentation above). This method is generally expected, but not absolutely required, to have the following properties:- Its execution does not cause any observable side effects.
- The computation is consistent with equals; that is,
Objects.equal
(a, b)
implies thatpredicate.apply(a) == predicate.apply(b))
.
-
toString
Returns a string representation of thisCharMatcher
, such asCharMatcher.or(WHITESPACE, JAVA_DIGIT)
.
-
any()
instead.