SpringCloud @RefreshScope重新整理機制淺析

@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Scope {
	/**
	 * Alias for {@link #scopeName}.
	 * @see #scopeName
	 */
	@AliasFor("scopeName")
	String value() default "";
	/**
	 *  singleton  表示該bean是單例的。(預設)
     *  prototype    表示該bean是多例的，即每次使用該bean時都會新建一個物件。
     *  request        在一次http請求中，一個bean對應一個範例。
     *  session        在一個httpSession中，一個bean對應一個範例
	 */
	@AliasFor("value")
	String scopeName() default "";
	/**
    *   DEFAULT			不使用代理。(預設)
	* 	NO				不使用代理，等價於DEFAULT。
	* 	INTERFACES		使用基於介面的代理(jdk dynamic proxy)。
	* 	TARGET_CLASS	使用基於類的代理(cglib)。
    */
	ScopedProxyMode proxyMode() default ScopedProxyMode.DEFAULT;
}

@Target({ ElementType.TYPE, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Scope("refresh")
@Documented
public @interface RefreshScope {
	/**
	 * @see Scope#proxyMode()
	 */
	ScopedProxyMode proxyMode() default ScopedProxyMode.TARGET_CLASS;
}

public interface Scope {
	/**
	 * Return the object with the given name from the underlying scope,
	 * {@link org.springframework.beans.factory.ObjectFactory#getObject() creating it}
	 * if not found in the underlying storage mechanism.
	 * <p>This is the central operation of a Scope, and the only operation
	 * that is absolutely required.
	 * @param name the name of the object to retrieve
	 * @param objectFactory the {@link ObjectFactory} to use to create the scoped
	 * object if it is not present in the underlying storage mechanism
	 * @return the desired object (never {@code null})
	 * @throws IllegalStateException if the underlying scope is not currently active
	 */
	Object get(String name, ObjectFactory<?> objectFactory);
	@Nullable
	Object remove(String name);
	void registerDestructionCallback(String name, Runnable callback);
	@Nullable
	Object resolveContextualObject(String key);
	@Nullable
	String getConversationId();
}

// ContextRefresher 外面使用它來進行方法呼叫 ============================== 我是分割線
	public synchronized Set<String> refresh() {
		Set<String> keys = refreshEnvironment();
		this.scope.refreshAll();
		return keys;
	}
// RefreshScope 內部程式碼  ============================== 我是分割線
	@ManagedOperation(description = "Dispose of the current instance of all beans in this scope and force a refresh on next method execution.")
	public void refreshAll() {
		super.destroy();
		this.context.publishEvent(new RefreshScopeRefreshedEvent());
	}
// GenericScope 裡的方法 ============================== 我是分割線
	//進行物件獲取，如果沒有就建立並放入快取
	@Override
	public Object get(String name, ObjectFactory<?> objectFactory) {
		BeanLifecycleWrapper value = this.cache.put(name,
				new BeanLifecycleWrapper(name, objectFactory));
		locks.putIfAbsent(name, new ReentrantReadWriteLock());
		try {
			return value.getBean();
		}
		catch (RuntimeException e) {
			this.errors.put(name, e);
			throw e;
		}
	}
	//進行快取的資料清理
	@Override
	public void destroy() {
		List<Throwable> errors = new ArrayList<Throwable>();
		Collection<BeanLifecycleWrapper> wrappers = this.cache.clear();
		for (BeanLifecycleWrapper wrapper : wrappers) {
			try {
				Lock lock = locks.get(wrapper.getName()).writeLock();
				lock.lock();
				try {
					wrapper.destroy();
				}
				finally {
					lock.unlock();
				}
			}
			catch (RuntimeException e) {
				errors.add(e);
			}
		}
		if (!errors.isEmpty()) {
			throw wrapIfNecessary(errors.get(0));
		}
		this.errors.clear();
	}