Guava - 布林值類

Booleans 是一個用於布林值基本型別的工具類。

類宣告

以下是com.google.common.primitives.Booleans類的宣告：

@GwtCompatible(emulated = true)
   public final class Booleans
      extends Object

方法

繼承的方法

此類繼承自以下類的方法：

• java.lang.Object

Booleans 類的示例

使用您選擇的任何編輯器建立以下 Java 程式，例如在C:/> Guava目錄下

GuavaTester.java

import java.util.List;
import com.google.common.primitives.Booleans;

public class GuavaTester {
   public static void main(String args[]) {
      GuavaTester tester = new GuavaTester();
      tester.testBooleans();
   }

   private void testBooleans() {
      boolean[] booleanArray = {true,true,false,true,true,false,false};

      //convert array of primitives to array of objects
      List<Boolean> objectArray = Booleans.asList(booleanArray);
      System.out.println(objectArray.toString());

      //convert array of objects to array of primitives
      booleanArray = Booleans.toArray(objectArray);
      System.out.print("[ ");

      for(int i = 0; i< booleanArray.length ; i++) {
         System.out.print(booleanArray[i] + " ");
      }

      System.out.println("]");

      //check if element is present in the list of primitives or not
      System.out.println("true is in list? " + Booleans.contains(booleanArray, true));

      //return the first index of element
      System.out.println("true position in list " + Booleans.indexOf(booleanArray, true));

      //Returns the count of true values
      System.out.println("true occured: " + Booleans.countTrue());

      //Returns the comparisons
      System.out.println("false Vs true: " + Booleans.compare(false, true));
      System.out.println("false Vs false: " + Booleans.compare(false, false));
      System.out.println("true Vs false: " + Booleans.compare(true, false));
      System.out.println("true Vs true: " + Booleans.compare(true, true));
   }
}

驗證結果

使用javac編譯器編譯類，如下所示：

C:\Guava>javac GuavaTester.java

現在執行 GuavaTester 來檢視結果。

C:\Guava>java GuavaTester

檢視結果。

[true, true, false, true, true, false, false]
[ true true false true true false false ]
true is in list? true
true position in list 0
true occured: 0
false Vs true: -1
false Vs false: 0
true Vs false: 1
true Vs true: 0