Guava Booleans類

Booleans是布林型基本的實用工具類。

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

方法繼承

這個類繼承了以下類方法：

• java.lang.Object

Booleans 範例

使用所選擇的任何編輯器建立下面的java程式 C:/> Guava

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編譯器編譯如下類

C:\Guava>javac GuavaTester.java

現在執行GuavaTester看到的結果

C:\Guava>java GuavaTester

看到結果。

[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