Java Stream.Builder add()用法及代碼示例

Stream.Builder add(T t)用於在流的構建階段將元素插入到元素中。它將元素添加到正在構建的流中。

用法:

default Stream.Builder<T> add(T t)

參數：此方法添加了強製參數t，該參數是要輸入到流中的元素。

Exceptions:當構建器已經轉換到構建狀態時，此方法引發IllegalStateException ：。這表示流已進入構建階段，現在不能更改。因此，無法將更多元素添加到流中。

下麵是說明add()方法的示例：

範例1：

// Java code to show the implementation 
// of Stream.Builder add(T t) 
  
import java.util.stream.Stream; 
  
class GFG { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
  
        // Declaring an empty Stream 
        Stream.Builder<String> str_b = Stream.builder(); 
  
        // Inserting elements into the stream 
        // using Stream.Builder add(T t) 
        str_b.add("Geeks"); 
        str_b.add("for"); 
        str_b.add("GeeksforGeeks"); 
        str_b.add("Data Structures"); 
        str_b.add("Geeks Classes"); 
  
        // Creating the String Stream 
        // The stream has now entered the built phase 
        Stream<String> s = str_b.build(); 
  
        // printing the elements 
        System.out.println("Stream successfully built"); 
        s.forEach(System.out::println); 
    } 
}

輸出：

Stream successfully built
Geeks
for
GeeksforGeeks
Data Structures
Geeks Classes

範例2：為了說明IllegalStateException

// Java code to show the implementation 
// of Stream.Builder add(T t) 
  
import java.util.stream.Stream; 
  
class GFG { 
  
    // Driver code 
    public static void main(String[] args) 
    { 
  
        // Declaring an empty Stream 
        Stream.Builder<String> str_b = Stream.builder(); 
  
        // using Stream.Builder add(T t) 
        str_b.add("5"); 
        str_b.add("6"); 
        str_b.add("7"); 
        str_b.add("8"); 
        str_b.add("9"); 
  
        // Creating the String Stream 
        // The stream has now entered the built phase 
        Stream<String> s = str_b.build(); 
  
        // printing the elements 
        System.out.println("Stream successfully built"); 
        s.forEach(System.out::println); 
  
        // Trying to add another element into the stream 
        // Since the Stream is in built phase 
        // This operation is not possible now 
        // Hence add() will throw exception now 
  
        try { 
            str_b.add("50"); 
        } 
        catch (Exception e) { 
            System.out.println("Exception thrown "
                               + "when now adding element into the stream:"
                               + e); 
        } 
    } 
}

輸出：

Stream successfully built
5
6
7
8
9
Exception thrown when now adding element into the stream:java.lang.IllegalStateException

相關用法

注：本文由純淨天空篩選整理自Sahil_Bansall大神的英文原創作品 Stream.Builder add() method in Java。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。