@GwtCompatible(emulated=true) public final class Ints extends Object
int primitives, that are not already found in either
Integer 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
int value.
|
static int |
MAX_POWER_OF_TWO
The largest power of two that can be represented as an
int.
|
| Modifier and Type | Method and Description |
|---|---|
static List |
asList(int... backingArray)
Returns a fixed-size list backed by the specified array, similar to
Arrays.
|
static int |
checkedCast(long value)
Returns the
int value that is equal to
value, if possible.
|
static int |
compare(int a, int b)
Compares the two specified
int values.
|
static int[] |
concat(int[]... arrays)
Returns the values from each provided array combined into a single array.
|
static boolean |
contains(int[] array, int target)
Returns
true if
target is present as an element anywhere in
array.
|
static int[] |
ensureCapacity(int[] array, int minLength, int padding)
Returns an array containing the same values as
array, but guaranteed to be of a specified minimum length.
|
static int |
fromByteArray(byte[] bytes)
Returns the
int value whose big-endian representation is stored in the first 4 bytes of
bytes; equivalent to
ByteBuffer.wrap(bytes).getInt().
|
static int |
fromBytes(byte b1, byte b2, byte b3, byte b4)
Returns the
int value whose byte representation is the given 4 bytes, in big-endian order; equivalent to
Ints.fromByteArray(new byte[] {b1, b2, b3, b4}).
|
static int |
hashCode(int value)
Returns a hash code for
value; equal to the result of invoking
((Integer) value).hashCode().
|
static int |
indexOf(int[] array, int target)
Returns the index of the first appearance of the value
target in
array.
|
static int |
indexOf(int[] array, int[] 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
int values separated by
separator.
|
static int |
lastIndexOf(int[] array, int target)
Returns the index of the last appearance of the value
target in
array.
|
static Comparator |
lexicographicalComparator()
Returns a comparator that compares two
int arrays lexicographically.
|
static int |
max(int... array)
Returns the greatest value present in
array.
|
static int |
min(int... array)
Returns the least value present in
array.
|
static int |
saturatedCast(long value)
Returns the
int nearest in value to
value.
|
static Converter |
stringConverter()
Returns a serializable converter object that converts between strings and integers using
Integer and
Integer.
|
static int[] |
toArray(Collection
Returns an array containing each value of
collection, converted to a
int value in the manner of
Number.
|
static byte[] |
toByteArray(int value)
Returns a big-endian representation of
value in a 4-element byte array; equivalent to
ByteBuffer.allocate(4).putInt(value).array().
|
static Integer |
tryParse(String
Parses the specified string as a signed decimal integer value.
|
public static final int BYTES
int value.
public static final int MAX_POWER_OF_TWO
int.
public static int hashCode(int value)
value; equal to the result of invoking
((Integer) value).hashCode().
value - a primitive
int value
public static int checkedCast(long value)
int value that is equal to
value, if possible.
value - any value in the range of the
int type
int value that equals
value
IllegalArgumentException - if
value is greater than
Integer.MAX_VALUE or less than
Integer.MIN_VALUE
public static int saturatedCast(long value)
int nearest in value to
value.
value - any
long value
int if it is in the range of the
int type,
Integer.MAX_VALUE if it is too large, or
Integer.MIN_VALUE if it is too small
public static int compare(int a,
int b)
int values. The sign of the value returned is the same as that of
((Integer) a).compareTo(b).
Note for Java 7 and later: this method should be treated as deprecated; use the equivalent Integer method instead.
a - the first
int to compare
b - the second
int 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(int[] array,
int target)
true if
target is present as an element anywhere in
array.
array - an array of
int values, possibly empty
target - a primitive
int value
true if
array[i] == target for some value of
i
public static int indexOf(int[] array,
int target)
target in
array.
array - an array of
int values, possibly empty
target - a primitive
int value
i for which
array[i] == target, or
-1 if no such index exists.
public static int indexOf(int[] array,
int[] 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(int[] array,
int target)
target in
array.
array - an array of
int values, possibly empty
target - a primitive
int value
i for which
array[i] == target, or
-1 if no such index exists.
public static int min(int... array)
array.
array - a
nonempty array of
int values
array that is less than or equal to every other value in the array
IllegalArgumentException - if
array is empty
public static int max(int... array)
array.
array - a
nonempty array of
int values
array that is greater than or equal to every other value in the array
IllegalArgumentException - if
array is empty
public static int[] concat(int[]... arrays)
concat(new int[] {a, b}, new int[] {}, new int[] {c} returns the array
{a, b, c}.
arrays - zero or more
int arrays
@GwtIncompatible(value="doesn\'t work") public static byte[] toByteArray(int value)
value in a 4-element byte array; equivalent to
ByteBuffer.allocate(4).putInt(value).array(). For example, the input value
0x12131415 would yield the byte array
{0x12, 0x13, 0x14, 0x15}.
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 int fromByteArray(byte[] bytes)
int value whose big-endian representation is stored in the first 4 bytes of
bytes; equivalent to
ByteBuffer.wrap(bytes).getInt(). For example, the input byte array
{0x12, 0x13, 0x14, 0x15, 0x33} would yield the
int value
0x12131415.
Arguably, it's preferable to use ByteBuffer; that library exposes much more flexibility at little cost in readability.
IllegalArgumentException - if
bytes has fewer than 4 elements
@GwtIncompatible(value="doesn\'t work") public static int fromBytes(byte b1, byte b2, byte b3, byte b4)
int value whose byte representation is the given 4 bytes, in big-endian order; equivalent to
Ints.fromByteArray(new byte[] {b1, b2, b3, b4}).
@Beta public static Converter<String ,Integer > stringConverter()
Integer.decode(java.lang.String) and
Integer.toString() .
public static int[] ensureCapacity(int[] 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, int... array)
int 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
int values, possibly empty
public static Comparator<int[]> lexicographicalComparator()
int arrays lexicographically. That is, it compares, using
compare(int, int)), 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,
[] < [1] < [1, 2] < [2].
The returned comparator is inconsistent with Object (since arrays support only identity equality), but it is consistent with Arrays.
public static int[] toArray(Collection<? extends Number > collection)
collection, converted to a
int value in the manner of
Number.intValue() .
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<Integer> before 12.0)
public static List<Integer > asList(int... 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 Integer 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
@Beta public static IntegertryParse(String string)
'-' (
'\u002D') is recognized as the minus sign.
Unlike Integer, 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 Integer for that version.
string - the string representation of an integer value
string, or
null if
string has a length of zero or cannot be parsed as an integer value