Stream.Builder accept(T t)用于在流的构建阶段将元素插入到元素中。它将元素添加到正在构建的流中。

用法:

void accept(T t)

参数：此方法接受强制参数t，该参数是要输入到流中的元素。

Exceptions:当构建器已经转换到构建状态时，此方法引发IllegalStateException ：。这表示流已进入构建阶段，现在不能更改。因此，无法将更多元素添加到流中。

下面是说明accept()方法的示例：

范例1：

// Java code to show the implementation

// of Stream.Builder accept(T t)

import java.util.stream.Stream;

class GFG {

// Driver code

public static void main(String[] args)

{

// Declaring an empty Stream

Stream.Builder str_b = Stream.builder();

// Inserting elements into the stream

// using Stream.Builder accept(T t)

str_b.accept("Geeks");

str_b.accept("for");

str_b.accept("GeeksforGeeks");

str_b.accept("Data Structures");

str_b.accept("Geeks Classes");

// Creating the String Stream

// The stream has now entered the built phase

Stream s = str_b.build();

// printing the elements

System.out.println("Stream successfully built");

s.forEach(System.out::println);

}

}

输出：

Stream successfully built

Geeks

for

GeeksforGeeks

Data Structures

Geeks Classes

范例2：为了说明IllegalStateException

// Java code to show the implementation

// of Stream.Builder accept(T t)

import java.util.stream.Stream;

class GFG {

// Driver code

public static void main(String[] args)

{

// Declaring an empty Stream

Stream.Builder str_b = Stream.builder();

// using Stream.Builder accept(T t)

str_b.accept("5");

str_b.accept("6");

str_b.accept("7");

str_b.accept("8");

str_b.accept("9");

// Creating the String Stream

// The stream has now entered the built phase

Stream 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 accept() will throw exception now

try {

str_b.accept("50");

}

catch (Exception e) {

System.out.println("Exception thrown "

+ "when now adding element into the stream:"

+ e);

}

}

}

输出：

Stream successfully built

5

6

7

8

9

Exception thrown when now adding element into the stream:java.lang.IllegalStateException