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java.lang.Objectcom.google.common.primitives.Ints
@GwtCompatible(emulated=true) public final class Ints
Static utility methods pertaining to int primitives, that are not
already found in either Integer or Arrays.
| Field Summary | |
|---|---|
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. |
| Method Summary | |
|---|---|
static List<Integer> |
asList(int... backingArray)
Returns a fixed-size list backed by the specified array, similar to Arrays.asList(Object[]). |
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 separator,
int... array)
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<int[]> |
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 int[] |
toArray(Collection<Integer> collection)
Copies a collection of Integer instances into a new array of
primitive int values. |
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 string)
Parses the specified string as a signed decimal integer value. |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
|---|
public static final int BYTES
int
value.
public static final int MAX_POWER_OF_TWO
int.
| Method Detail |
|---|
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_VALUEpublic 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).
a - the first int to compareb - 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 emptytarget - 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 emptytarget - 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 targettarget - 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 emptytarget - 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 emptypublic 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 emptypublic 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.newDataOutput() 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}).
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 arrayminLength - the minimum length the returned array must guaranteepadding - 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 String join(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 emptypublic 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.equals(Object) (since arrays support only identity equality), but
it is consistent with Arrays.equals(int[], int[]).
public static int[] toArray(Collection<Integer> collection)
Integer instances into a new array of
primitive int 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 Integer objects
collection, in the
same order, converted to primitives
NullPointerException - if collection or any of its elements
is nullpublic 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 @CheckForNull @GwtIncompatible(value="TODO") public static Integer tryParse(String string)
'-' ('\u002D') is recognized as the
minus sign.
Unlike Integer.parseInt(String), this method returns
null instead of throwing an exception if parsing fails.
Note that strings prefixed with ASCII '+' are rejected, even
under JDK 7, despite the change to Integer.parseInt(String) 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
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