public Feign internalBuild()

in spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-sentinel/src/main/java/com/alibaba/cloud/sentinel/feign/SentinelFeign.java [81:164]
70 lines of code
9 McCabe index (conditional complexity)

		public Feign internalBuild() {
			super.invocationHandlerFactory(new InvocationHandlerFactory() {
				@Override
				public InvocationHandler create(Target target,
						Map<Method, MethodHandler> dispatch) {
					GenericApplicationContext gctx = (GenericApplicationContext) Builder.this.applicationContext;
					BeanDefinition def = gctx.getBeanDefinition(target.type().getName());
					FeignClientFactoryBean feignClientFactoryBean;

					// If you need the attributes to be resolved lazily, set the property value to true.
					Boolean isLazyInit = applicationContext.getEnvironment()
							.getProperty(FEIGN_LAZY_ATTR_RESOLUTION, Boolean.class, false);
					if (isLazyInit) {
						/*
						 * Due to the change of the initialization sequence,
						 * BeanFactory.getBean will cause a circular dependency. So
						 * FeignClientFactoryBean can only be obtained from BeanDefinition
						 */
						feignClientFactoryBean = (FeignClientFactoryBean) def
								.getAttribute("feignClientsRegistrarFactoryBean");
					}
					else {
						feignClientFactoryBean = (FeignClientFactoryBean) applicationContext
								.getBean("&" + target.type().getName());
					}
					Class fallback = feignClientFactoryBean.getFallback();
					Class fallbackFactory = feignClientFactoryBean.getFallbackFactory();
					String beanName = feignClientFactoryBean.getContextId();
					if (!StringUtils.hasText(beanName)) {
						beanName = (String) getFieldValue(feignClientFactoryBean, "name");
					}

					Object fallbackInstance;
					FallbackFactory fallbackFactoryInstance;
					// check fallback and fallbackFactory properties
					if (void.class != fallback) {
						fallbackInstance = getFromContext(beanName, "fallback", fallback,
								target.type());
						return new SentinelInvocationHandler(target, dispatch,
								new FallbackFactory.Default(fallbackInstance));
					}
					if (void.class != fallbackFactory) {
						fallbackFactoryInstance = (FallbackFactory) getFromContext(
								beanName, "fallbackFactory", fallbackFactory,
								FallbackFactory.class);
						return new SentinelInvocationHandler(target, dispatch,
								fallbackFactoryInstance);
					}

					return new SentinelInvocationHandler(target, dispatch);
				}

				private Object getFromContext(String name, String type,
						Class fallbackType, Class targetType) {
					Object fallbackInstance = feignClientFactory.getInstance(name,
							fallbackType);
					if (fallbackInstance == null) {
						throw new IllegalStateException(String.format(
								"No %s instance of type %s found for feign client %s",
								type, fallbackType, name));
					}
					// when fallback is a FactoryBean, should determine the type of instance
					if (fallbackInstance instanceof FactoryBean<?> factoryBean) {
						try {
							fallbackInstance = factoryBean.getObject();
						}
						catch (Exception e) {
							throw new IllegalStateException(type + " create fail", e);
						}
						fallbackType = fallbackInstance.getClass();
					}

					if (!targetType.isAssignableFrom(fallbackType)) {
						throw new IllegalStateException(String.format(
								"Incompatible %s instance. Fallback/fallbackFactory of type %s is not assignable to %s for feign client %s",
								type, fallbackType, targetType, name));
					}
					return fallbackInstance;
				}
			});

			super.contract(new SentinelContractHolder(contract));
			return super.internalBuild();
		}