# 子應用程式 - 掛載 { #sub-applications-mounts }

若你需要兩個彼此獨立的 FastAPI 應用程式，各自擁有獨立的 OpenAPI 與文件 UI，你可以有一個主應用，並「掛載」一個（或多個）子應用程式。

## 掛載一個 **FastAPI** 應用程式 { #mounting-a-fastapi-application }

「掛載」是指在某個特定路徑下加入一個完全「獨立」的應用程式，之後該應用程式會負責處理該路徑底下的一切，使用該子應用程式中宣告的*路徑操作（path operation）*。

### 頂層應用程式 { #top-level-application }

先建立主（頂層）**FastAPI** 應用程式以及它的*路徑操作*：

{* ../../docs_src/sub_applications/tutorial001_py310.py hl[3, 6:8] *}

### 子應用程式 { #sub-application }

Only keep parentheses if they exist in the source text. Do not add parentheses to terms that do not have them.

### Avoiding Repetition in Translation

  return *factories;
}

static tracing::FactoryFunction default_factory;

void RegisterTracingEngineFactory(const string& name, FactoryFunction factory) {
  assert((!GetFactories().count(name)) ||
         (GetFactories()[name] == factory) &&
             "Duplicate tracing factory registration");
  GetFactories()[name] = factory;
}

absl::Status SetDefaultTracingEngine(const char* name) {

      val buffer = cursor.data
      var i = cursor.start
      val end = cursor.end
      if (buffer != null) {
        while (i < end) {
          keyIndex %= keyLength // Reassign to prevent overflow breaking counter.

          // Byte xor is experimental in Kotlin so we coerce bytes to int, xor them
          // and convert back to byte.
          val bufferInt: Int = buffer[i].toInt()

		}
		sm.Queued.Avg.Bytes += peer.Queued.Avg.Bytes
		sm.Queued.Avg.Count += peer.Queued.Avg.Count
		sm.Queued.Curr.Bytes += peer.Queued.Curr.Bytes
		sm.Queued.Curr.Count += peer.Queued.Curr.Count
		if peer.Queued.Max.Count > sm.Queued.Max.Count {
			sm.Queued.Max.Bytes = peer.Queued.Max.Bytes
			sm.Queued.Max.Count = peer.Queued.Max.Count
		}
		sm.ReplicaCount += peer.ReplicaCount
		sm.ReplicaSize += peer.ReplicaSize

        // Then
        assertArrayEquals(testFileId, customRequest.getFileId(), "Custom implementation should store file ID correctly");
        assertEquals(1, customRequest.getSetCount(), "Should track set count correctly");
    }

   *
   * <p>For example, {@code Splitter.on(',').limit(3).split("a,b,c,d")} returns an iterable
   * containing {@code ["a", "b", "c,d"]}. When omitting empty strings, the omitted strings do not
   * count. Hence, {@code Splitter.on(',').limit(3).omitEmptyStrings().split("a,,,b,,,c,d")} returns
   * an iterable containing {@code ["a", "b", "c,d"]}. When trim is requested, all entries are

     */
    public void setName(final String name) {
        this.name = name;
    }

    /**
     * Sets the maximum number of redirects to follow.
     * @param maxRedirectCount The maximum redirect count.
     */
    public void setMaxRedirectCount(final int maxRedirectCount) {
        this.maxRedirectCount = maxRedirectCount;
    }

            // Check that it's public
            assertTrue("Method should be public", java.lang.reflect.Modifier.isPublic(method.getModifiers()));

            // Check parameter count
            assertEquals("Method should have no parameters", 0, method.getParameterCount());

        } catch (NoSuchMethodException e) {
            fail("getSearchEngineHttpAddress method should exist");
        }

    }

    @Override
    public int remove(@Nullable Object key, int occurrences) {
      checkNonnegative(occurrences, "occurrences");
      if (occurrences == 0) {
        return count(key);
      }
      Collection<V> collection = unfiltered.asMap().get(key);
      if (collection == null) {
        return 0;
      }
      @SuppressWarnings("unchecked") // key is equal to a K, if not a K itself