本文整理了Java中reactor.core.publisher.Mono.expand()方法的一些代码示例，展示了Mono.expand()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Mono.expand()方法的具体详情如下：
包路径：reactor.core.publisher.Mono
类名称：Mono
方法名：expand

Mono.expand介绍

[英]Recursively expand elements into a graph and emit all the resulting element using a breadth-first traversal strategy.

That is: emit the value from this Mono first, then it each at a first level of recursion and emit all of the resulting values, then expand all of these at a second level and so on...

For example, given the hierarchical structure

A 
- AA 
- aa1 
- AB 
- ab1 
- a1

Expands Mono.just(A) into

A 
AA 
AB 
a1 
aa1 
ab1

[中]递归地将元素展开为一个图，并使用广度优先遍历策略发出所有生成的元素。
也就是说：首先从这个Mono中发出值，然后在递归的第一级对每个值进行处理，并发出所有结果值，然后在第二级展开所有这些值，以此类推。。。
例如，考虑到层次结构

A 
- AA 
- aa1 
- AB 
- ab1 
- a1

扩展单声道。仅（A）进入<<1$>>

代码示例

代码示例来源：origin: reactor/reactor-core

return expand(expander, Queues.SMALL_BUFFER_SIZE);

代码示例来源：origin: reactor/reactor-core

@Test
public void empty() {
  StepVerifier.create(Mono.<Integer>empty()
      .expand(countDown))
        .verifyComplete();
}

代码示例来源：origin: reactor/reactor-core

@Test
public void expanderThrows() {
  StepVerifier.create(Mono.just(10)
              .expand(v -> {
                throw new IllegalStateException("boom");
              }))
        .expectNext(10)
        .verifyErrorMessage("boom");
}

代码示例来源：origin: reactor/reactor-core

@Test
public void javadocExampleBreadthFirst() {
  List<String> breadthFirstExpected = Arrays.asList(
      "A",
      "AA",
      "AB",
      "a1",
      "aa1",
      "ab1");
  StepVerifier.create(
      Mono.just(ROOT)
        .expand(v -> Flux.fromIterable(v.children))
        .map(n -> n.name))
        .expectNextSequence(breadthFirstExpected)
        .verifyComplete();
}

代码示例来源：origin: reactor/reactor-core

@Test
public void error() {
  StepVerifier.create(Mono.<Integer>error(new IllegalStateException("boom"))
      .expand(countDown))
        .verifyErrorMessage("boom");
}

代码示例来源：origin: reactor/reactor-core

@Test
public void recursiveCountdown() {
  StepVerifier.create(Mono.just(10)
              .expand(countDown))
        .expectNext(10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
        .verifyComplete();
}

代码示例来源：origin: reactor/reactor-core

@Test
public void expanderReturnsNull() {
  StepVerifier.create(Mono.just(10)
              .expand(v -> null))
        .expectNext(10)
        .verifyError(NullPointerException.class);
}

代码示例来源：origin: reactor/reactor-core

@Test
public void recursiveCountdownTake() {
  StepVerifier.create(Mono.just(10)
              .expand(countDown)
              .take(5)
  )
        .expectNext(10, 9, 8, 7, 6)
        .verifyComplete();
}

代码示例来源：origin: reactor/reactor-core

@Test
public void recursiveCountdownLoop() {
  for (int i = 0; i < 1000; i = (i < 100 ? i + 1 : i + 50)) {
    String tag = "i = " + i + ", strategy = breadth";
    List<Integer> list = new ArrayList<>();
    StepVerifier.create(Mono.just(i)
                .expand(countDown))
          .expectSubscription()
          .recordWith(() -> list)
          .expectNextCount(i + 1)
          .as(tag)
          .verifyComplete();
    for (int j = 0; j <= i; j++) {
      assertThat(list.get(j).intValue())
          .as(tag + ", " + list)
          .isEqualTo(i - j);
    }
  }
}

代码示例来源：origin: reactor/reactor-core

@Test(timeout = 5000)
public void breadthFirst() {
  FluxExpandTest.Node root = createTest();
  StepVerifier.create(Mono.just(root)
              .expand(v -> Flux.fromIterable(v.children))
              .map(v -> v.name))
        .expectNext(
            "root",
            "1", "2", "3", "4",
            "11", "21", "22", "31", "32", "33", "41", "42", "43", "44",
            "221", "321", "331", "332", "421", "431", "432", "441", "442", "443",
            "3321", "4321", "4421", "4431", "4432"
        )
        .verifyComplete();
}

代码示例来源：origin: reactor/reactor-core

@Test
public void breadthFirstAsync() {
  FluxExpandTest.Node root = createTest();
  StepVerifier.create(Mono.just(root)
              .expand(v -> Flux.fromIterable(v.children).subscribeOn(Schedulers.elastic()))
              .map(v -> v.name))
        .expectNext(
            "root",
            "1", "2", "3", "4",
            "11", "21", "22", "31", "32", "33", "41", "42", "43", "44",
            "221", "321", "331", "332", "421", "431", "432", "441", "442", "443",
            "3321", "4321", "4421", "4431", "4432"
        )
        .expectComplete()
        .verify(Duration.ofSeconds(5));
}

代码示例来源：origin: reactor/reactor-core

@Test
public void recursiveCountdownBackpressure() {
  StepVerifier.create(Mono.just(10)
              .expand(countDown),
      StepVerifierOptions.create()
                .initialRequest(0)
                .checkUnderRequesting(false))
        .thenRequest(1)
        .expectNext(10)
        .thenRequest(3)
        .expectNext(9, 8, 7)
        .thenRequest(4)
        .expectNext(6, 5, 4, 3)
        .thenRequest(3)
        .expectNext(2, 1, 0)
        .verifyComplete();
}

代码示例来源：origin: io.projectreactor/reactor-core

return expand(expander, Queues.SMALL_BUFFER_SIZE);