Guava Booleans类
Booleans是原始类型Boolean的一个实用类。它提供了与布尔基元有关的静态实用方法,这些方法在布尔或数组中都没有找到。
声明 :
@GwtCompatible(emulated=true)public final class Booleansextends Object
下面给出的是Guava Booleans类提供的一些方法。
异常情况:
ensureCapacity : 如果minLength或padding为负数,则出现IllegalArgumentException。toArray : 如果集合或其任何元素为空,则出现NullPointerException。下表显示了Guava Booleans类提供的一些其他方法。
下面给出了一些例子,展示了Guava Booleans类方法的实现。
例1 :
// Java code to show implementation// of Guava Booleans.asList() method import com.google.common.primitives.Booleans;import java.util.*; class GFG { // Driver method public static void main(String[] args) { boolean arr[] = { true, false, true, false, true }; // Using Booleans.asList() method which // converts array of primitives to array of objects List<Boolean> myList = Booleans.asList(arr); // Displaying the elements System.out.println(myList); }}
输出:
[true, false, true, false, true]
例2 :
// Java code to show implementation// of Guava Booleans.toArray() method import com.google.common.primitives.Booleans;import java.util.*; class GFG { // Driver method public static void main(String[] args) { List<Boolean> myList = Arrays.asList(true, false, true, false, true); // Using Booleans.toArray() method which // converts a List of Booleans to an // array of boolean boolean[] arr = Booleans.toArray(myList); // Displaying the elements System.out.println(Arrays.toString(arr)); }}输出:
[true, false, true, false, true]
例3 :
// Java code to show implementation// of Guava Booleans.concat() method import com.google.common.primitives.Booleans;import java.util.*; class GFG { // Driver method public static void main(String[] args) { boolean[] arr1 = { true, false, true }; boolean[] arr2 = { false, true }; // Using Booleans.concat() method which // combines arrays from specified // arrays into a single array boolean[] arr = Booleans.concat(arr1, arr2); // Displaying the elements System.out.println(Arrays.toString(arr)); }}输出:
[true, false, true, false, true]
例4 :
// Java code to show implementation// of Guava Booleans.contains() method import com.google.common.primitives.Booleans; class GFG { // Driver method public static void main(String[] args) { boolean[] arr = { true, false, true, false, true }; // Using Booleans.contains() method which // checks if element is present in array // or not System.out.println(Booleans.contains(arr, true)); System.out.println(Booleans.contains(arr, false)); }}输出 :
truetrue
例5 :
// Java code to show implementation// of Guava Booleans.compare() method import com.google.common.primitives.Booleans; class GFG { // Driver method public static void main(String[] args) { // To compare true vs true System.out.println(Booleans.compare(true, true)); }}输出:
0
例6 :
// Java code to show implementation// of Guava Booleans.indexOf() method import com.google.common.primitives.Booleans; class GFG { // Driver method public static void main(String[] args) { boolean[] arr = { true, false, true, false, true }; // To print index of first occurrence of false System.out.println(Booleans.indexOf(arr, false)); }}输出:
1
