@CheckReturnValue @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 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. |
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 char |
saturatedCast(long value)
Returns the
char nearest in value to value . |
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.public static int hashCode(char value)
value
; equal to the result of invoking
((Character) value).hashCode()
.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 java.util.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 emptypublic 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(value="doesn\'t work") 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(value="doesn\'t work") 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(value="doesn\'t work") 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. 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 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 © 2010-2015. All Rights Reserved.