this.attributes = attributes;
    }

    @Override
    public Map<String, Object> toSource() {
        final Map<String, Object> sourceMap = new HashMap<>();
        if (name != null) {
            sourceMap.put("name", name);
        }
        if (attributes != null) {
            sourceMap.putAll(attributes);
        }
        return sourceMap;
    }

    Collection<V> collection = asMap().get(key);
    return collection != null && collection.remove(value);
  }

  @CanIgnoreReturnValue
  @Override
  public boolean put(@ParametricNullness K key, @ParametricNullness V value) {
    return get(key).add(value);
  }

  @CanIgnoreReturnValue
  @Override
  public boolean putAll(@ParametricNullness K key, Iterable<? extends V> values) {

            Metadata metadata = it.next();
            if (metadata instanceof PluginsMetadata pluginsMetadata) {
                it.remove();
                processedPlugins.put(pluginsMetadata.getGroupId(), pluginsMetadata);
            }
        }
    }

    @Override
    public Collection<? extends Metadata> prepare(Collection<? extends Artifact> artifacts) {

     * Stores a parameter value with the specified key.
     *
     * @param key the parameter key, must not be null
     * @param value the parameter value, may be null
     */
    public void put(final String key, final Object value) {
        params.put(key, value);
    }

    /**
     * Retrieves a parameter value by key.
     *
     * @param key the parameter key to look up
     * @return the parameter value if found, null otherwise

            lifecycle
                    .getLifecyclePhases()
                    .forEach((phase, lifecyclePhase) -> parseLifecyclePhaseDefinitions(plugins, phase, lifecyclePhase));
            lfs.put(id, PluginContainer.newBuilder().plugins(plugins.values()).build());
        });
        return lfs;
    }

    static void parseLifecyclePhaseDefinitions(Map<String, Plugin> plugins, String phase, LifecyclePhase goals) {

        metrics.put("totalRotations", totalKeyRotations.get());
        metrics.put("lastRotationTime", lastKeyRotationTime.get());
        metrics.put("bytesEncryptedSinceLastRotation", bytesEncrypted.get());
        metrics.put("timeSinceLastRotation", System.currentTimeMillis() - encryptionStartTime);
        metrics.put("rotationBytesLimit", keyRotationBytesLimit);
        metrics.put("rotationTimeLimit", keyRotationTimeLimit);

---

回到之前的代码示例，**FastAPI** 将会：

* 校验 `GET` 和 `PUT` 请求的路径中是否包含 `item_id`。
* 校验 `GET` 和 `PUT` 请求中的 `item_id` 是否为 `int` 类型。
    * 如果不是，客户端会看到清晰有用的错误信息。
* 对于 `GET` 请求，检查是否存在名为 `q` 的可选查询参数（如 `http://127.0.0.1:8000/items/foo?q=somequery`）。
    * 因为参数 `q` 被声明为 `= None`，所以它是可选的。
    * 如果没有 `None`，它就是必需的（就像 `PUT` 情况下的请求体）。
* 对于发送到 `/items/{item_id}` 的 `PUT` 请求，把请求体作为 JSON 读取：
    * 检查是否存在必需属性 `name`，且为 `str`。

     * @return the previous value associated with key, or null if no mapping existed
     */
    @Override
    public Object put(final String key, final Object value) {
        return parent.put(key, value);
    }

    /**
     * Removes the mapping for a key from this map if it is present.
     *
     * @param key the key whose mapping is to be removed from the map

    }

    /** Map for normalizing protocols */
    protected static final Map<String, String> CANONICAL_PROTOCOLS = newHashMap();
    static {
        CANONICAL_PROTOCOLS.put("wsjar", "jar"); // Proprietary protocol used by WebSphere for jar files
        CANONICAL_PROTOCOLS.put("vfsfile", "file"); // Proprietary protocol used by JBossAS5 for file system
    }

    /**
     * Opens a URL and returns an {@link InputStream}.
     *

        final Lock acquiredAggregatorLock;
        final OwnerReentrantLock acquiredProjectLock;

        ProjectLock(MavenSession session, MojoDescriptor mojoDescriptor) {
            mojos.put(Thread.currentThread(), mojoDescriptor);
            boolean aggregator = mojoDescriptor.isAggregator();
            acquiredAggregatorLock = aggregator ? aggregatorLock.writeLock() : aggregatorLock.readLock();