Java Spliterator estimateSize()用法及代码示例

Java Interface Spliterator 的 estimateSize() 方法用于估计剩余元素的数量，如果无限、未知或计算成本太高，则返回 Long.MAX_VALUE。

用法

以下是 estimateSize() 方法的声明-

long estimateSize()

参数

此方法不接受任何参数。

estimateSize() 方法返回元素的估计大小或 Long.MAX_VALUE 如果无限、未知或计算成本太高。

异常

兼容版本

Java 1.8 及以上

例子1

import java.util.*;
public class InterfaceSpliteratorEstimateSizeExample1 {  
     public static void main(String args[]){
    	   //Create an array list
         ArrayList<Integer> al1 = new ArrayList<>();             
         //Add values in the list.
         al1.add(1);
         al1.add(-2);
         al1.add(3);
         al1.add(-4);                                                     
         //Getting Spliterator object
         Spliterator<Integer> splitr = al1.spliterator();  
         //Print EstimateSize 
         System.out.println("Estimate size of ArrayList:" + splitr.estimateSize());
         //Printelements of arraylist.              
         System.out.println("Elements of arraylist:");     
         while(splitr.tryAdvance((n) -> System.out.println(n)));
         }
}

输出：

Estimate size of ArrayList:4
Elements of arraylist:
1
-2
3
-4

例子2

import java.util.*;
public class InterfaceSpliteratorEstimateSizeExample2 {  
     public static void main(String args[]){
    	    List<String> nameList = Arrays.asList("Rahul", "Abhi", "Suresh", "Rani", "Nikki", "Rosy", "Prem");
    	   Spliterator<String> splitr = nameList.spliterator();
    	   //Print EstimateSize 
         System.out.println("Estimate size of List:" + splitr.estimateSize());   	
         }
}

输出：

Estimate size of List:7

例子3

import java.util.*;
public class InterfaceSpliteratorEstimateSizeExample3 {  
     public static void main(String args[]){
    	      List<String> names = new ArrayList<>();
    		names.add("Rahul");
    		names.add("Rohit");
    		names.add("Surya");    			
    		//Getting Spliterator object
    		Spliterator<String> namesSpliterator = names.spliterator();
    		System.out.println("Estimate size:" + namesSpliterator.estimateSize());
    		System.out.println("Name present in List:");
    		namesSpliterator.forEachRemaining(System.out::println);	
    		System.out.println("Again Estimate size is:" + namesSpliterator.estimateSize());
            }
}

输出：

Estimate size:3
Name present in List:
Rahul
Rohit
Surya
Again Estimate size is:0

相关用法

注：本文由纯净天空筛选整理自 Java Spliterator estimateSize() Method。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。