@CheckReturnValue @GwtCompatible(emulated=true) public final class Chars extends Object
Static utility methods pertaining to 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
The number of bytes required to represent a primitive char value.
public static int hashCode(char value)
Returns a hash code for value; equal to the result of invoking ((Character) value).hashCode().
value - a primitive char valuepublic static char checkedCast(long value)
Returns the char value that is equal to value, if possible.
value - any value in the range of the char typechar value that equals valueIllegalArgumentException - if value is greater than Character.MAX_VALUE or less than Character.MIN_VALUEpublic static char saturatedCast(long value)
Returns the 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)
Compares the two specified 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)
Returns 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 ipublic static int indexOf(char[] array,
char target)
Returns the index of the first appearance of the value 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)
Returns the start position of the first occurrence of the specified 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 targettarget - the array to search for as a sub-sequence of arraypublic static int lastIndexOf(char[] array,
char target)
Returns the index of the last appearance of the value 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)
Returns the least value present in 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)
Returns the greatest value present in 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)
Returns the values from each provided array combined into a single array. For example, 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)
Returns a big-endian representation of 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 to get a growable buffer.
@GwtIncompatible(value="doesn\'t work") public 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(). 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)
Returns the 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)
Returns an array containing the same values as 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 minLengthIllegalArgumentException - if minLength or padding is negativepublic static String join(String separator, char... array)
Returns a string containing the supplied 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()
Returns a comparator that compares two 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)
Copies a collection of 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)
Returns a fixed-size list backed by the specified array, similar to 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 list