Java IntStream.Builder add()方法

IntStream.Builder add(int t)用于在流的构建阶段向元素中插入一个元素。它将一个元素添加到正在构建的流中。

语法

default IntStream.Builder add(int t)

参数。这个方法接受一个强制参数 t ，它是要输入到流中的元素。

异常： 该方法抛出 IllegalStateException： 当构建器已经过渡到构建状态。这意味着流已经进入了构建阶段，现在不能改变。因此，没有更多的元素可以被添加到流中。

下面是说明add()方法的例子。

例1 :

// Java code to show the implementation// of IntStream.Builder add(int t)  import java.util.stream.IntStream;  class GFG {      // Driver code    public static void main(String[] args)    {          // Declaring an empty Stream        IntStream.Builder b = IntStream.builder();          // Inserting elements into the stream        // using IntStream.Builder add(int t)        b.add(4);        b.add(5);        b.add(6);        b.add(7);          // Creating the Stream        // The stream has now entered the built phase        // printing the elements        System.out.println("Stream successfully built");        b.build().forEach(System.out::println);    }}

输出。

Stream successfully built4567

例2： 为了说明IllegalStateException

// Java code to show the implementation// of IntStream.Builder add(T t)  import java.util.stream.IntStream;  class GFG {      // Driver code    public static void main(String[] args)    {          // Declaring an empty Stream        IntStream.Builder b = IntStream.builder();          // using IntStream.Builder add(T t)        b.add(4);        b.add(5);        b.add(6);        b.add(7);          // Creating the Stream        // The stream has now entered the built phase        // printing the elements        System.out.println("Stream successfully built");        b.build().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 {            b.add(50);        }        catch (Exception e) {            System.out.println("Exception thrown "                               + "when now adding element into the stream: "                               + e);        }    }}

输出。

Stream successfully built4567Exception thrown when now adding element into the stream: java.lang.IllegalStateException