@GwtCompatible public final class Longs extends Object
long
primitives, that are not already found in either
Long
or
Arrays
.
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
long value.
|
static long |
MAX_POWER_OF_TWO
The largest power of two that can be represented as a
long .
|
Modifier and Type | Method and Description |
---|---|
static List |
asList(long... backingArray)
Returns a fixed-size list backed by the specified array, similar to
Arrays .
|
static int |
compare(long a, long b)
Compares the two specified
long values.
|
static long[] |
concat(long[]... arrays)
Returns the values from each provided array combined into a single array.
|
static boolean |
contains(long[] array, long target)
Returns
true if
target is present as an element anywhere in
array .
|
static long[] |
ensureCapacity(long[] array, int minLength, int padding)
Returns an array containing the same values as
array , but guaranteed to be of a specified minimum length.
|
static long |
fromByteArray(byte[] bytes)
Returns the
long value whose big-endian representation is stored in the first 8 bytes of
bytes ; equivalent to
ByteBuffer.wrap(bytes).getLong() .
|
static long |
fromBytes(byte b1, byte b2, byte b3, byte b4, byte b5, byte b6, byte b7, byte b8)
Returns the
long value whose byte representation is the given 8 bytes, in big-endian order; equivalent to
Longs.fromByteArray(new byte[] {b1, b2, b3, b4, b5, b6, b7, b8}) .
|
static int |
hashCode(long value)
Returns a hash code for
value ; equal to the result of invoking
((Long) value).hashCode() .
|
static int |
indexOf(long[] array, long target)
Returns the index of the first appearance of the value
target in
array .
|
static int |
indexOf(long[] array, long[] 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
Returns a string containing the supplied
long values separated by
separator .
|
static int |
lastIndexOf(long[] array, long target)
Returns the index of the last appearance of the value
target in
array .
|
static Comparator |
lexicographicalComparator()
Returns a comparator that compares two
long arrays lexicographically.
|
static long |
max(long... array)
Returns the greatest value present in
array .
|
static long |
min(long... array)
Returns the least value present in
array .
|
static Converter |
stringConverter()
Returns a serializable converter object that converts between strings and longs using
Long and
Long .
|
static long[] |
toArray(Collection
Returns an array containing each value of
collection , converted to a
long value in the manner of
Number .
|
static byte[] |
toByteArray(long value)
Returns a big-endian representation of
value in an 8-element byte array; equivalent to
ByteBuffer.allocate(8).putLong(value).array() .
|
static Long |
tryParse(String
Parses the specified string as a signed decimal long value.
|
static Long |
tryParse(String
Parses the specified string as a signed long value using the specified radix.
|
public static final int BYTES
long
value.
public static final long MAX_POWER_OF_TWO
long
.
public static int hashCode(long value)
value
; equal to the result of invoking
((Long) value).hashCode()
.
This method always return the value specified by Long
in java, which might be different from ((Long) value).hashCode()
in GWT because Long
in GWT does not obey the JRE contract.
value
- a primitive
long
value
public static int compare(long a, long b)
long
values. The sign of the value returned is the same as that of
((Long) a).compareTo(b)
.
Note for Java 7 and later: this method should be treated as deprecated; use the equivalent Long
method instead.
a
- the first
long
to compare
b
- the second
long
to compare
a
is less than
b
; a positive value if
a
is greater than
b
; or zero if they are equal
public static boolean contains(long[] array, long target)
true
if
target
is present as an element anywhere in
array
.
array
- an array of
long
values, possibly empty
target
- a primitive
long
value
true
if
array[i] == target
for some value of
i
public static int indexOf(long[] array, long target)
target
in
array
.
array
- an array of
long
values, possibly empty
target
- a primitive
long
value
i
for which
array[i] == target
, or
-1
if no such index exists.
public static int indexOf(long[] array, long[] 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(long[] array, long target)
target
in
array
.
array
- an array of
long
values, possibly empty
target
- a primitive
long
value
i
for which
array[i] == target
, or
-1
if no such index exists.
public static long min(long... array)
array
.
array
- a
nonempty array of
long
values
array
that is less than or equal to every other value in the array
IllegalArgumentException
- if
array
is empty
public static long max(long... array)
array
.
array
- a
nonempty array of
long
values
array
that is greater than or equal to every other value in the array
IllegalArgumentException
- if
array
is empty
public static long[] concat(long[]... arrays)
concat(new long[] {a, b}, new long[] {}, new long[] {c}
returns the array
{a, b, c}
.
arrays
- zero or more
long
arrays
public static byte[] toByteArray(long value)
value
in an 8-element byte array; equivalent to
ByteBuffer.allocate(8).putLong(value).array()
. For example, the input value
0x1213141516171819L
would yield the byte array
{0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19}
.
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.
public static long fromByteArray(byte[] bytes)
long
value whose big-endian representation is stored in the first 8 bytes of
bytes
; equivalent to
ByteBuffer.wrap(bytes).getLong()
. For example, the input byte array
{0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19}
would yield the
long
value
0x1213141516171819L
.
Arguably, it's preferable to use ByteBuffer
; that library exposes much more flexibility at little cost in readability.
IllegalArgumentException
- if
bytes
has fewer than 8 elements
public static long fromBytes(byte b1, byte b2, byte b3, byte b4, byte b5, byte b6, byte b7, byte b8)
long
value whose byte representation is the given 8 bytes, in big-endian order; equivalent to
Longs.fromByteArray(new byte[] {b1, b2, b3, b4, b5, b6, b7, b8})
.
@Beta public static LongtryParse(String string)
'-'
(
'\u002D'
) is recognized as the minus sign.
Unlike Long
, this method returns null
instead of throwing an exception if parsing fails. Additionally, this method only accepts ASCII digits, and returns null
if non-ASCII digits are present in the string.
Note that strings prefixed with ASCII '+'
are rejected, even under JDK 7, despite the change to Long
for that version.
string
- the string representation of a long value
string
, or
null
if
string
has a length of zero or cannot be parsed as a long value
@Beta public static LongtryParse(String string, int radix)
'-'
(
'\u002D'
) is recognized as the minus sign.
Unlike Long
, this method returns null
instead of throwing an exception if parsing fails. Additionally, this method only accepts ASCII digits, and returns null
if non-ASCII digits are present in the string.
Note that strings prefixed with ASCII '+'
are rejected, even under JDK 7, despite the change to Long
for that version.
string
- the string representation of an long value
radix
- the radix to use when parsing
string
using
radix
, or
null
if
string
has a length of zero or cannot be parsed as a long value
IllegalArgumentException
- if
radix < Character.MIN_RADIX
or
radix > Character.MAX_RADIX
@Beta public static Converter<String ,Long > stringConverter()
Long.decode(java.lang.String)
and
Long.toString()
.
public static long[] ensureCapacity(long[] 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 array
minLength
- the minimum length the returned array must guarantee
padding
- an extra amount to "grow" the array by if growth is necessary
array
, with guaranteed minimum length
minLength
IllegalArgumentException
- if
minLength
or
padding
is negative
public static Stringjoin(String separator, long... array)
long
values separated by
separator
. For example,
join("-", 1L, 2L, 3L)
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
long
values, possibly empty
public static Comparator<long[]> lexicographicalComparator()
long
arrays lexicographically. That is, it compares, using
compare(long, long)
), 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,
[] < [1L] < [1L, 2L] < [2L]
.
The returned comparator is inconsistent with Object
(since arrays support only identity equality), but it is consistent with Arrays
.
public static long[] toArray(Collection<? extends Number > collection)
collection
, converted to a
long
value in the manner of
Number.longValue()
.
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
Number
instances
collection
, in the same order, converted to primitives
NullPointerException
- if
collection
or any of its elements is null
Collection<Long>
before 12.0)
public static List<Long > asList(long... 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 Long
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