private void checkBlock4RestTemplate()

in spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-sentinel/src/main/java/com/alibaba/cloud/sentinel/custom/SentinelBeanPostProcessor.java [107:174]
66 lines of code
13 McCabe index (conditional complexity)

	private void checkBlock4RestTemplate(Class<?> blockClass, String blockMethod,
			String beanName, String type) {
		if (blockClass == void.class && !StringUtils.hasLength(blockMethod)) {
			return;
		}
		if (blockClass != void.class && !StringUtils.hasLength(blockMethod)) {
			log.error(
					"{} class attribute exists but {} method attribute is not exists in bean[{}]",
					type, type, beanName);
			throw new IllegalArgumentException(type + " class attribute exists but "
					+ type + " method attribute is not exists in bean[" + beanName + "]");
		}
		else if (blockClass == void.class && StringUtils.hasLength(blockMethod)) {
			log.error(
					"{} method attribute exists but {} class attribute is not exists in bean[{}]",
					type, type, beanName);
			throw new IllegalArgumentException(type + " method attribute exists but "
					+ type + " class attribute is not exists in bean[" + beanName + "]");
		}
		Class[] args;
		if (type.equals(SentinelConstants.URLCLEANER_TYPE)) {
			args = new Class[] {String.class};
		}
		else {
			args = new Class[] {HttpRequest.class, byte[].class,
					ClientHttpRequestExecution.class, BlockException.class};
		}
		String argsStr = Arrays.toString(
				Arrays.stream(args).map(clazz -> clazz.getSimpleName()).toArray());
		Method foundMethod = ClassUtils.getStaticMethod(blockClass, blockMethod, args);
		if (foundMethod == null) {
			log.error(
					"{} static method can not be found in bean[{}]. The right method signature is {}#{}{}, please check your class name, method name and arguments",
					type, beanName, blockClass.getName(), blockMethod, argsStr);
			throw new IllegalArgumentException(type
					+ " static method can not be found in bean[" + beanName
					+ "]. The right method signature is " + blockClass.getName() + "#"
					+ blockMethod + argsStr
					+ ", please check your class name, method name and arguments");
		}

		Class<?> standardReturnType;
		if (type.equals(SentinelConstants.URLCLEANER_TYPE)) {
			standardReturnType = String.class;
		}
		else {
			standardReturnType = ClientHttpResponse.class;
		}

		if (!standardReturnType.isAssignableFrom(foundMethod.getReturnType())) {
			log.error("{} method return value in bean[{}] is not {}: {}#{}{}", type,
					beanName, standardReturnType.getName(), blockClass.getName(),
					blockMethod, argsStr);
			throw new IllegalArgumentException(type + " method return value in bean["
					+ beanName + "] is not " + standardReturnType.getName() + ": "
					+ blockClass.getName() + "#" + blockMethod + argsStr);
		}
		if (type.equals(SentinelConstants.BLOCK_TYPE)) {
			BlockClassRegistry.updateBlockHandlerFor(blockClass, blockMethod,
					foundMethod);
		}
		else if (type.equals(SentinelConstants.FALLBACK_TYPE)) {
			BlockClassRegistry.updateFallbackFor(blockClass, blockMethod, foundMethod);
		}
		else {
			BlockClassRegistry.updateUrlCleanerFor(blockClass, blockMethod, foundMethod);
		}
	}