@CheckReturnValue @GwtCompatible public final class Booleans extends Object
Static utility methods pertaining to boolean primitives, that are not already found in either Boolean or Arrays.
See the Guava User Guide article on primitive utilities.
| Modifier and Type | Method and Description |
|---|---|
static List<Boolean> |
asList(boolean... backingArray)
Returns a fixed-size list backed by the specified array, similar to
Arrays.asList(Object[]). |
static int |
compare(boolean a,
boolean b)
Compares the two specified
boolean values in the standard way (false is considered less than true). |
static boolean[] |
concat(boolean[]... arrays)
Returns the values from each provided array combined into a single array.
|
static boolean |
contains(boolean[] array,
boolean target)
Returns
true if target is present as an element anywhere in array. |
static int |
countTrue(boolean... values)
Returns the number of
values that are true. |
static boolean[] |
ensureCapacity(boolean[] 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 |
hashCode(boolean value)
Returns a hash code for
value; equal to the result of invoking ((Boolean) value).hashCode(). |
static int |
indexOf(boolean[] array,
boolean target)
Returns the index of the first appearance of the value
target in array. |
static int |
indexOf(boolean[] array,
boolean[] 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,
boolean... array)
Returns a string containing the supplied
boolean values separated by separator. |
static int |
lastIndexOf(boolean[] array,
boolean target)
Returns the index of the last appearance of the value
target in array. |
static Comparator<boolean[]> |
lexicographicalComparator()
Returns a comparator that compares two
boolean arrays lexicographically. |
static boolean[] |
toArray(Collection<Boolean> collection)
Copies a collection of
Boolean instances into a new array of primitive boolean values. |
public static int hashCode(boolean value)
Returns a hash code for value; equal to the result of invoking ((Boolean) value).hashCode().
value - a primitive boolean valuepublic static int compare(boolean a,
boolean b)
Compares the two specified boolean values in the standard way (false is considered less than true). The sign of the value returned is the same as that of ((Boolean) a).compareTo(b).
Note for Java 7 and later: this method should be treated as deprecated; use the equivalent Boolean.compare(boolean, boolean) method instead.
a - the first boolean to compareb - the second boolean to comparea is true, a negative number if only b is true, or zero if a == bpublic static boolean contains(boolean[] array,
boolean target)
Returns true if target is present as an element anywhere in array.
Note: consider representing the array as a BitSet instead, replacing Booleans.contains(array, true) with !bitSet.isEmpty() and Booleans.contains(array, false) with bitSet.nextClearBit(0) == sizeOfBitSet.
array - an array of boolean values, possibly emptytarget - a primitive boolean valuetrue if array[i] == target for some value of ipublic static int indexOf(boolean[] array,
boolean target)
Returns the index of the first appearance of the value target in array.
Note: consider representing the array as a BitSet instead, and using BitSet.nextSetBit(int) or BitSet.nextClearBit(int).
array - an array of boolean values, possibly emptytarget - a primitive boolean valuei for which array[i] == target, or -1 if no such index exists.public static int indexOf(boolean[] array,
boolean[] 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(boolean[] array,
boolean target)
Returns the index of the last appearance of the value target in array.
array - an array of boolean values, possibly emptytarget - a primitive boolean valuei for which array[i] == target, or -1 if no such index exists.public static boolean[] concat(boolean[]... arrays)
Returns the values from each provided array combined into a single array. For example, concat(new boolean[] {a, b}, new boolean[] {}, new boolean[] {c} returns the array {a, b, c}.
arrays - zero or more boolean arrayspublic static boolean[] ensureCapacity(boolean[] 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, boolean... array)
Returns a string containing the supplied boolean values separated by separator. For example, join("-", false, true, false) returns the string "false-true-false".
separator - the text that should appear between consecutive values in the resulting string (but not at the start or end)array - an array of boolean values, possibly emptypublic static Comparator<boolean[]> lexicographicalComparator()
Returns a comparator that compares two boolean arrays lexicographically. That is, it compares, using compare(boolean, boolean)), 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, [] < [false] < [false, true] < [true].
The returned comparator is inconsistent with Object.equals(Object) (since arrays support only identity equality), but it is consistent with Arrays.equals(boolean[], boolean[]).
public static boolean[] toArray(Collection<Boolean> collection)
Copies a collection of Boolean instances into a new array of primitive boolean values.
Elements are copied from the argument collection as if by collection.toArray(). Calling this method is as thread-safe as calling that method.
Note: consider representing the collection as a BitSet instead.
collection - a collection of Boolean objectscollection, in the same order, converted to primitivesNullPointerException - if collection or any of its elements is nullpublic static List<Boolean> asList(boolean... 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 Boolean 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 int countTrue(boolean... values)
Returns the number of values that are true.