@GwtCompatible(emulated=true) public final class Chars extends Object
char
primitives, that are not already found in
either Character
or Arrays
.
All the operations in this class treat char
values strictly numerically; they are
neither Unicode-aware nor locale-dependent.
See the Guava User Guide article on primitive utilities.
Modifier and Type | Field and Description |
---|---|
static int |
BYTES
The number of bytes required to represent a primitive
char value. |
Modifier and Type | Method and Description |
---|---|
static List<Character> |
asList(char... backingArray)
Returns a fixed-size list backed by the specified array, similar to
Arrays.asList(Object[]) . |
static char |
checkedCast(long value)
Returns the
char value that is equal to value , if possible. |
static int |
compare(char a,
char b)
Compares the two specified
char values. |
static char[] |
concat(char[]... arrays)
Returns the values from each provided array combined into a single array.
|
static char |
constrainToRange(char value,
char min,
char max)
Returns the value nearest to
value which is within the closed range [min..max] . |
static boolean |
contains(char[] array,
char target)
Returns
true if target is present as an element anywhere in array . |
static char[] |
ensureCapacity(char[] array,
int minLength,
int padding)
Returns an array containing the same values as
array , but guaranteed to be of a
specified minimum length. |
static char |
fromByteArray(byte[] bytes)
Returns the
char value whose big-endian representation is stored in the first 2 bytes
of bytes ; equivalent to ByteBuffer.wrap(bytes).getChar() . |
static char |
fromBytes(byte b1,
byte b2)
Returns the
char value whose byte representation is the given 2 bytes, in big-endian
order; equivalent to Chars.fromByteArray(new byte[] {b1, b2}) . |
static int |
hashCode(char value)
Returns a hash code for
value ; equal to the result of invoking ((Character)
value).hashCode() . |
static int |
indexOf(char[] array,
char target)
Returns the index of the first appearance of the value
target in array . |
static int |
indexOf(char[] array,
char[] target)
Returns the start position of the first occurrence of the specified
target within
array , or -1 if there is no such occurrence. |
static String |
join(String separator,
char... array)
Returns a string containing the supplied
char values separated by separator . |
static int |
lastIndexOf(char[] array,
char target)
Returns the index of the last appearance of the value
target in array . |
static Comparator<char[]> |
lexicographicalComparator()
Returns a comparator that compares two
char arrays lexicographically; not advisable
for sorting user-visible strings as the ordering may not match the conventions of the user's
locale. |
static char |
max(char... array)
Returns the greatest value present in
array . |
static char |
min(char... array)
Returns the least value present in
array . |
static void |
reverse(char[] array)
Reverses the elements of
array . |
static void |
reverse(char[] array,
int fromIndex,
int toIndex)
Reverses the elements of
array between fromIndex inclusive and toIndex
exclusive. |
static char |
saturatedCast(long value)
Returns the
char nearest in value to value . |
static void |
sortDescending(char[] array)
Sorts the elements of
array in descending order. |
static void |
sortDescending(char[] array,
int fromIndex,
int toIndex)
Sorts the elements of
array between fromIndex inclusive and toIndex
exclusive in descending order. |
static char[] |
toArray(Collection<Character> collection)
Copies a collection of
Character instances into a new array of primitive char
values. |
static byte[] |
toByteArray(char value)
Returns a big-endian representation of
value in a 2-element byte array; equivalent to
ByteBuffer.allocate(2).putChar(value).array() . |
public static final int BYTES
char
value.
Java 8 users: use Character.BYTES
instead.
public static int hashCode(char value)
value
; equal to the result of invoking ((Character)
value).hashCode()
.
Java 8 users: use Character.hashCode(char)
instead.
value
- a primitive char
valuepublic static char checkedCast(long value)
char
value that is equal to value
, if possible.value
- any value in the range of the char
typechar
value that equals value
IllegalArgumentException
- if value
is greater than Character.MAX_VALUE
or less than Character.MIN_VALUE
public static char saturatedCast(long value)
char
nearest in value to value
.value
- any long
valuechar
if it is in the range of the char
type,
Character.MAX_VALUE
if it is too large, or Character.MIN_VALUE
if it is too
smallpublic static int compare(char a, char b)
char
values. The sign of the value returned is the same as
that of ((Character) a).compareTo(b)
.
Note for Java 7 and later: this method should be treated as deprecated; use the
equivalent Character.compare(char, char)
method instead.
a
- the first char
to compareb
- the second char
to comparea
is less than b
; a positive value if a
is
greater than b
; or zero if they are equalpublic static boolean contains(char[] array, char target)
true
if target
is present as an element anywhere in array
.array
- an array of char
values, possibly emptytarget
- a primitive char
valuetrue
if array[i] == target
for some value of i
public static int indexOf(char[] array, char target)
target
in array
.array
- an array of char
values, possibly emptytarget
- a primitive char
valuei
for which array[i] == target
, or -1
if no
such index exists.public static int indexOf(char[] array, char[] target)
target
within
array
, or -1
if there is no such occurrence.
More formally, returns the lowest index i
such that Arrays.copyOfRange(array,
i, i + target.length)
contains exactly the same elements as target
.
array
- the array to search for the sequence target
target
- the array to search for as a sub-sequence of array
public static int lastIndexOf(char[] array, char target)
target
in array
.array
- an array of char
values, possibly emptytarget
- a primitive char
valuei
for which array[i] == target
, or -1
if no
such index exists.public static char min(char... array)
array
.array
- a nonempty array of char
valuesarray
that is less than or equal to every other value in
the arrayIllegalArgumentException
- if array
is emptypublic static char max(char... array)
array
.array
- a nonempty array of char
valuesarray
that is greater than or equal to every other value
in the arrayIllegalArgumentException
- if array
is empty@Beta public static char constrainToRange(char value, char min, char max)
value
which is within the closed range [min..max]
.
If value
is within the range [min..max]
, value
is returned
unchanged. If value
is less than min
, min
is returned, and if value
is greater than max
, max
is returned.
value
- the char
value to constrainmin
- the lower bound (inclusive) of the range to constrain value
tomax
- the upper bound (inclusive) of the range to constrain value
toIllegalArgumentException
- if min > max
public static char[] concat(char[]... arrays)
concat(new char[] {a, b}, new char[] {}, new char[] {c}
returns the array {a, b, c}
.arrays
- zero or more char
arrays@GwtIncompatible public static byte[] toByteArray(char value)
value
in a 2-element byte array; equivalent to
ByteBuffer.allocate(2).putChar(value).array()
. For example, the input value '\\u5432'
would yield the byte array {0x54, 0x32}
.
If you need to convert and concatenate several values (possibly even of different types),
use a shared ByteBuffer
instance, or use ByteStreams.newDataOutput()
to get a growable buffer.
@GwtIncompatible public static char fromByteArray(byte[] bytes)
char
value whose big-endian representation is stored in the first 2 bytes
of bytes
; equivalent to ByteBuffer.wrap(bytes).getChar()
. For example, the
input byte array {0x54, 0x32}
would yield the char
value '\\u5432'
.
Arguably, it's preferable to use ByteBuffer
; that library exposes much more
flexibility at little cost in readability.
IllegalArgumentException
- if bytes
has fewer than 2 elements@GwtIncompatible public static char fromBytes(byte b1, byte b2)
char
value whose byte representation is the given 2 bytes, in big-endian
order; equivalent to Chars.fromByteArray(new byte[] {b1, b2})
.public static char[] ensureCapacity(char[] array, int minLength, int padding)
array
, but guaranteed to be of a
specified minimum length. If array
already has a length of at least minLength
,
it is returned directly. Otherwise, a new array of size minLength + padding
is
returned, containing the values of array
, and zeroes in the remaining places.array
- the source arrayminLength
- the minimum length the returned array must guaranteepadding
- an extra amount to "grow" the array by if growth is necessaryarray
, with guaranteed minimum length minLength
IllegalArgumentException
- if minLength
or padding
is negativepublic static String join(String separator, char... array)
char
values separated by separator
.
For example, join("-", '1', '2', '3')
returns the string "1-2-3"
.separator
- the text that should appear between consecutive values in the resulting string
(but not at the start or end)array
- an array of char
values, possibly emptypublic static Comparator<char[]> lexicographicalComparator()
char
arrays lexicographically; not advisable
for sorting user-visible strings as the ordering may not match the conventions of the user's
locale. That is, it compares, using compare(char, char)
), the first pair of values
that follow any common prefix, or when one array is a prefix of the other, treats the shorter
array as the lesser. For example, [] < ['a'] < ['a', 'b'] < ['b']
.
The returned comparator is inconsistent with Object.equals(Object)
(since arrays
support only identity equality), but it is consistent with Arrays.equals(char[],
char[])
.
public static char[] toArray(Collection<Character> collection)
Character
instances into a new array of primitive char
values.
Elements are copied from the argument collection as if by collection.toArray()
.
Calling this method is as thread-safe as calling that method.
collection
- a collection of Character
objectscollection
, in the same order, converted
to primitivesNullPointerException
- if collection
or any of its elements is nullpublic static void sortDescending(char[] array)
array
in descending order.public static void sortDescending(char[] array, int fromIndex, int toIndex)
array
between fromIndex
inclusive and toIndex
exclusive in descending order.public static void reverse(char[] array)
array
. This is equivalent to Collections.reverse(Chars.asList(array))
, but is likely to be more efficient.public static void reverse(char[] array, int fromIndex, int toIndex)
array
between fromIndex
inclusive and toIndex
exclusive. This is equivalent to Collections.reverse(Chars.asList(array).subList(fromIndex, toIndex))
, but is likely to be more
efficient.IndexOutOfBoundsException
- if fromIndex < 0
, toIndex > array.length
, or
toIndex > fromIndex
public static List<Character> asList(char... backingArray)
Arrays.asList(Object[])
. The list supports List.set(int, Object)
, but any attempt to
set a value to null
will result in a NullPointerException
.
The returned list maintains the values, but not the identities, of Character
objects
written to or read from it. For example, whether list.get(0) == list.get(0)
is true for
the returned list is unspecified.
backingArray
- the array to back the listCopyright © 2010–2019. All rights reserved.