@Beta @GwtCompatible(emulated=true) public abstract class CharMatcher extends java.lang.Object implements Predicate<java.lang.Character>
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 character c
for which this.matches(c)
returns true
".
Note: 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
.
Modifier and Type | Class and Description |
---|---|
private static class |
CharMatcher.And |
private static class |
CharMatcher.BitSetMatcher |
(package private) static class |
CharMatcher.FastMatcher
A matcher for which precomputation will not yield any significant benefit.
|
(package private) static class |
CharMatcher.NegatedFastMatcher |
private static class |
CharMatcher.NegatedMatcher |
private static class |
CharMatcher.Or |
private static class |
CharMatcher.RangesMatcher |
Modifier and Type | Field and Description |
---|---|
static CharMatcher |
ANY
Matches any character.
|
static CharMatcher |
ASCII
Determines whether a character is ASCII, meaning that its code point is less than 128.
|
static CharMatcher |
BREAKING_WHITESPACE
Determines whether a character is a breaking whitespace (that is, a whitespace which can be
interpreted as a break between words for formatting purposes).
|
(package private) java.lang.String |
description |
static CharMatcher |
DIGIT
Determines whether a character is a digit according to
Unicode.
|
private static int |
DISTINCT_CHARS |
static CharMatcher |
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.
|
static CharMatcher |
JAVA_DIGIT
Determines whether a character is a digit according to Java's definition.
|
static CharMatcher |
JAVA_ISO_CONTROL
Determines whether a character is an ISO control character as specified by
Character.isISOControl(char) . |
static CharMatcher |
JAVA_LETTER
Determines whether a character is a letter according to Java's definition.
|
static CharMatcher |
JAVA_LETTER_OR_DIGIT
Determines whether a character is a letter or digit according to Java's definition.
|
static CharMatcher |
JAVA_LOWER_CASE
Determines whether a character is lower case according to Java's definition.
|
static CharMatcher |
JAVA_UPPER_CASE
Determines whether a character is upper case according to Java's definition.
|
private static java.lang.String |
NINES |
static CharMatcher |
NONE
Matches no characters.
|
static CharMatcher |
SINGLE_WIDTH
Determines whether a character is single-width (not double-width).
|
static CharMatcher |
WHITESPACE
Determines whether a character is whitespace according to the latest Unicode standard, as
illustrated
here.
|
(package private) static int |
WHITESPACE_MULTIPLIER |
(package private) static int |
WHITESPACE_SHIFT |
(package private) static java.lang.String |
WHITESPACE_TABLE |
private static java.lang.String |
ZEROES |
Modifier | Constructor and Description |
---|---|
protected |
CharMatcher()
Constructor for use by subclasses.
|
(package private) |
CharMatcher(java.lang.String description)
Sets the
toString() from the given description. |
Modifier and Type | Method and Description |
---|---|
CharMatcher |
and(CharMatcher other)
Returns a matcher that matches any character matched by both this matcher and
other . |
static CharMatcher |
anyOf(java.lang.CharSequence sequence)
Returns a
char matcher that matches any character present in the given character
sequence. |
boolean |
apply(java.lang.Character character)
Deprecated.
Provided only to satisfy the
Predicate interface; use matches(char)
instead. |
java.lang.String |
collapseFrom(java.lang.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(java.lang.CharSequence sequence)
Returns the number of matching characters found in a character sequence.
|
private java.lang.String |
finishCollapseFrom(java.lang.CharSequence sequence,
int start,
int end,
char replacement,
java.lang.StringBuilder builder,
boolean inMatchingGroup) |
static CharMatcher |
forPredicate(Predicate<? super java.lang.Character> predicate)
Returns a matcher with identical behavior to the given
Character -based predicate, but
which operates on primitive char instances instead. |
int |
indexIn(java.lang.CharSequence sequence)
Returns the index of the first matching character in a character sequence, or
-1 if no
matching character is present. |
int |
indexIn(java.lang.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 a
char matcher that matches any character in a given range (both endpoints are
inclusive). |
(package private) static CharMatcher |
inRange(char startInclusive,
char endInclusive,
java.lang.String description) |
static CharMatcher |
is(char match)
Returns a
char matcher that matches only one specified character. |
private static CharMatcher |
isEither(char match1,
char match2) |
static CharMatcher |
isNot(char match)
Returns a
char matcher that matches any character except the one specified. |
private static boolean |
isSmall(int totalCharacters,
int tableLength) |
int |
lastIndexIn(java.lang.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(java.lang.CharSequence sequence)
Returns
true if a character sequence contains only matching characters. |
boolean |
matchesAnyOf(java.lang.CharSequence sequence)
Returns
true if a character sequence contains at least one matching character. |
boolean |
matchesNoneOf(java.lang.CharSequence sequence)
Returns
true if a character sequence contains no matching characters. |
CharMatcher |
negate()
Returns a matcher that matches any character not matched by this matcher.
|
static CharMatcher |
noneOf(java.lang.CharSequence sequence)
Returns a
char matcher that matches any character not present in the given character
sequence. |
CharMatcher |
or(CharMatcher other)
Returns a matcher that matches any character matched by either this matcher or
other . |
CharMatcher |
precomputed()
Returns a
char matcher functionally equivalent to this one, but which may be faster to
query than the original; your mileage may vary. |
(package private) CharMatcher |
precomputedInternal()
This is the actual implementation of
precomputed() , but we bounce calls through a
method on Platform so that we can have different behavior in GWT. |
private static CharMatcher |
precomputedPositive(int totalCharacters,
java.util.BitSet table,
java.lang.String description)
Helper method for
precomputedInternal() that doesn't test if the negation is cheaper. |
java.lang.String |
removeFrom(java.lang.CharSequence sequence)
Returns a string containing all non-matching characters of a character sequence, in order.
|
java.lang.String |
replaceFrom(java.lang.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.
|
java.lang.String |
replaceFrom(java.lang.CharSequence sequence,
java.lang.CharSequence replacement)
Returns a string copy of the input character sequence, with each character that matches this
matcher replaced by a given replacement sequence.
|
java.lang.String |
retainFrom(java.lang.CharSequence sequence)
Returns a string containing all matching characters of a character sequence, in order.
|
(package private) void |
setBits(java.util.BitSet table)
Sets bits in
table matched by this matcher. |
private static java.lang.String |
showCharacter(char c) |
java.lang.String |
toString()
Returns a string representation of this
CharMatcher , such as
CharMatcher.or(WHITESPACE, JAVA_DIGIT) . |
java.lang.String |
trimAndCollapseFrom(java.lang.CharSequence sequence,
char replacement)
Collapses groups of matching characters exactly as
collapseFrom(java.lang.CharSequence, char) does, except that
groups of matching characters at the start or end of the sequence are removed without
replacement. |
java.lang.String |
trimFrom(java.lang.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.
|
java.lang.String |
trimLeadingFrom(java.lang.CharSequence sequence)
Returns a substring of the input character sequence that omits all characters this matcher
matches from the beginning of the string.
|
java.lang.String |
trimTrailingFrom(java.lang.CharSequence sequence)
Returns a substring of the input character sequence that omits all characters this matcher
matches from the end of the string.
|
(package private) CharMatcher |
withToString(java.lang.String description)
Subclasses should provide a new CharMatcher with the same characteristics as
this ,
but with their toString method overridden with the new description. |
public static final CharMatcher BREAKING_WHITESPACE
WHITESPACE
for a
discussion of that term.public static final CharMatcher ASCII
private static final java.lang.String ZEROES
private static final java.lang.String NINES
public static final CharMatcher DIGIT
inRange('0', '9')
.public static final CharMatcher JAVA_DIGIT
inRange('0', '9')
.public static final CharMatcher JAVA_LETTER
inRange('a', 'z').or(inRange('A', 'Z'))
.public static final CharMatcher JAVA_LETTER_OR_DIGIT
public static final CharMatcher JAVA_UPPER_CASE
public static final CharMatcher JAVA_LOWER_CASE
public static final CharMatcher JAVA_ISO_CONTROL
Character.isISOControl(char)
.public static final CharMatcher INVISIBLE
public static final CharMatcher SINGLE_WIDTH
false
(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.
public static final CharMatcher ANY
public static final CharMatcher NONE
final java.lang.String description
private static final int DISTINCT_CHARS
static final java.lang.String WHITESPACE_TABLE
static final int WHITESPACE_MULTIPLIER
static final int WHITESPACE_SHIFT
public static final CharMatcher WHITESPACE
Note: as the Unicode definition evolves, we will modify this constant to keep it up to date.
CharMatcher(java.lang.String description)
toString()
from the given description.protected CharMatcher()
toString()
to provide a useful description.private static java.lang.String showCharacter(char c)
public static CharMatcher is(char match)
char
matcher that matches only one specified character.public static CharMatcher isNot(char match)
char
matcher that matches any character except the one specified.
To negate another CharMatcher
, use negate()
.
public static CharMatcher anyOf(java.lang.CharSequence sequence)
char
matcher that matches any character present in the given character
sequence.private static CharMatcher isEither(char match1, char match2)
public static CharMatcher noneOf(java.lang.CharSequence sequence)
char
matcher that matches any character not present in the given character
sequence.public static CharMatcher inRange(char startInclusive, char endInclusive)
char
matcher that matches any character in a given range (both endpoints are
inclusive). For example, to match any lowercase letter of the English alphabet, use CharMatcher.inRange('a', 'z')
.java.lang.IllegalArgumentException
- if endInclusive < startInclusive
static CharMatcher inRange(char startInclusive, char endInclusive, java.lang.String description)
public static CharMatcher forPredicate(Predicate<? super java.lang.Character> predicate)
Character
-based predicate, but
which operates on primitive char
instances instead.public abstract boolean matches(char c)
public CharMatcher negate()
public CharMatcher and(CharMatcher other)
other
.public CharMatcher or(CharMatcher other)
other
.public CharMatcher precomputed()
char
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.
CharMatcher withToString(java.lang.String description)
this
,
but with their toString
method overridden with the new description.
This is unsupported by default.
@GwtIncompatible(value="java.util.BitSet") CharMatcher precomputedInternal()
precomputed()
, but we bounce calls through a
method on Platform
so that we can have different behavior in GWT.
This implementation tries to be smart in a number of ways. It recognizes cases where the negation is cheaper to precompute than the matcher itself; it tries to build small hash tables for matchers that only match a few characters, and so on. In the worst-case scenario, it constructs an eight-kilobyte bit array and queries that. In many situations this produces a matcher which is faster to query than the original.
@GwtIncompatible(value="java.util.BitSet") private static CharMatcher precomputedPositive(int totalCharacters, java.util.BitSet table, java.lang.String description)
precomputedInternal()
that doesn't test if the negation is cheaper.@GwtIncompatible(value="SmallCharMatcher") private static boolean isSmall(int totalCharacters, int tableLength)
@GwtIncompatible(value="java.util.BitSet") void setBits(java.util.BitSet table)
table
matched by this matcher.public boolean matchesAnyOf(java.lang.CharSequence sequence)
true
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 returns true
or the end is reached.
sequence
- the character sequence to examine, possibly emptytrue
if this matcher matches at least one character in the sequencepublic boolean matchesAllOf(java.lang.CharSequence sequence)
true
if a character sequence contains only matching characters.
The default implementation iterates over the sequence, invoking matches(char)
for each
character, until this returns false
or the end is reached.
sequence
- the character sequence to examine, possibly emptytrue
if this matcher matches every character in the sequence, including when
the sequence is emptypublic boolean matchesNoneOf(java.lang.CharSequence sequence)
true
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 returns false
or the end is reached.
sequence
- the character sequence to examine, possibly emptytrue
if this matcher matches every character in the sequence, including when
the sequence is emptypublic int indexIn(java.lang.CharSequence sequence)
-1
if no
matching character is present.
The default implementation iterates over the sequence in forward order calling matches(char)
for each character.
sequence
- the character sequence to examine from the beginning-1
if no character matchespublic int indexIn(java.lang.CharSequence sequence, int start)
-1
if no character matches after that position.
The default implementation iterates over the sequence in forward order, beginning at start
, calling matches(char)
for each character.
sequence
- the character sequence to examinestart
- the first index to examine; must be nonnegative and no greater than sequence.length()
start
,
or -1
if no character matchesjava.lang.IndexOutOfBoundsException
- if start is negative or greater than sequence.length()
public int lastIndexIn(java.lang.CharSequence sequence)
-1
if no
matching character is present.
The default implementation iterates over the sequence in reverse order calling matches(char)
for each character.
sequence
- the character sequence to examine from the end-1
if no character matchespublic int countIn(java.lang.CharSequence sequence)
@CheckReturnValue public java.lang.String removeFrom(java.lang.CharSequence sequence)
CharMatcher.is('a').removeFrom("bazaar")
... returns "bzr"
.@CheckReturnValue public java.lang.String retainFrom(java.lang.CharSequence sequence)
CharMatcher.is('a').retainFrom("bazaar")
... returns "aaa"
.@CheckReturnValue public java.lang.String replaceFrom(java.lang.CharSequence sequence, char replacement)
CharMatcher.is('a').replaceFrom("radar", 'o')
... returns "rodor"
.
The default implementation uses indexIn(CharSequence)
to find the first matching
character, then iterates the remainder of the sequence calling matches(char)
for each
character.
sequence
- the character sequence to replace matching characters inreplacement
- the character to append to the result string in place of each matching
character in sequence
@CheckReturnValue public java.lang.String replaceFrom(java.lang.CharSequence sequence, java.lang.CharSequence replacement)
CharMatcher.is('a').replaceFrom("yaha", "oo")
... returns "yoohoo"
.
Note: If the replacement is a fixed string with only one character, you are better
off calling replaceFrom(CharSequence, char)
directly.
sequence
- the character sequence to replace matching characters inreplacement
- the characters to append to the result string in place of each matching
character in sequence
@CheckReturnValue public java.lang.String trimFrom(java.lang.CharSequence sequence)
CharMatcher.anyOf("ab").trimFrom("abacatbab")
... returns "cat"
.
Note that:
CharMatcher.inRange('\0', ' ').trimFrom(str)
... is equivalent to String.trim()
.@CheckReturnValue public java.lang.String trimLeadingFrom(java.lang.CharSequence sequence)
CharMatcher.anyOf("ab").trimLeadingFrom("abacatbab")
... returns "catbab"
.@CheckReturnValue public java.lang.String trimTrailingFrom(java.lang.CharSequence sequence)
CharMatcher.anyOf("ab").trimTrailingFrom("abacatbab")
... returns "abacat"
.@CheckReturnValue public java.lang.String collapseFrom(java.lang.CharSequence sequence, char replacement)
CharMatcher.anyOf("eko").collapseFrom("bookkeeper", '-')
... returns "b-p-r"
.
The default implementation uses indexIn(CharSequence)
to find the first matching
character, then iterates the remainder of the sequence calling matches(char)
for each
character.
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 in sequence
@CheckReturnValue public java.lang.String trimAndCollapseFrom(java.lang.CharSequence sequence, char replacement)
collapseFrom(java.lang.CharSequence, char)
does, except that
groups of matching characters at the start or end of the sequence are removed without
replacement.private java.lang.String finishCollapseFrom(java.lang.CharSequence sequence, int start, int end, char replacement, java.lang.StringBuilder builder, boolean inMatchingGroup)
@Deprecated public boolean apply(java.lang.Character character)
Predicate
interface; use matches(char)
instead.Predicate
input
. This method is generally
expected, but not absolutely required, to have the following properties:
Objects.equal
(a, b)
implies that predicate.apply(a) ==
predicate.apply(b))
.
public java.lang.String toString()
CharMatcher
, such as
CharMatcher.or(WHITESPACE, JAVA_DIGIT)
.toString
in class java.lang.Object