Logging all request mappings and their parameters in Spring

java

/**
 * A listener to listen on {@link ContextRefreshedEvent}.
 */
@Log4j
@Component
public class EndpointsListener implements ApplicationListener<ContextRefreshedEvent> {
    /**
     * Provides access to all view controllers defined in {@link SpringConfig}.
     */
    private final HandlerMapping viewControllerHandlerMapping;

    /**
     * Constructor.
     *
     * @param viewControllerHandlerMapping View Controller Handler Mapping.
     */
    public EndpointsListener(HandlerMapping viewControllerHandlerMapping) {
        this.viewControllerHandlerMapping = viewControllerHandlerMapping;
    }

    /**
     * On context refresh, get all request handler mappings and create a list.
     * Also get the view controller mappings from {@link #viewControllerHandlerMapping} and add to the list.
     *
     * @param event A {@link ContextRefreshedEvent}.
     */
    @SneakyThrows
    @Override
    public void onApplicationEvent(ContextRefreshedEvent event) {
        ApplicationContext applicationContext = event.getApplicationContext();
        List<CustomMapping> mappings = new ArrayList<>();
        for (Map.Entry<RequestMappingInfo, HandlerMethod> entry : applicationContext
                .getBean(RequestMappingHandlerMapping.class).getHandlerMethods().entrySet()) {
            RequestMappingInfo requestMappingInfo = entry.getKey();
            HandlerMethod handlerMethod = entry.getValue();
            CustomMapping mapping = new CustomMapping();
            mapping.setMethods(requestMappingInfo.getMethodsCondition().getMethods()
                    .stream().map(Enum::name).collect(Collectors.toSet()));
            mapping.setPatterns(requestMappingInfo.getPatternsCondition().getPatterns());
            Arrays.stream(handlerMethod.getMethodParameters()).forEach(methodParameter -> {
                CustomParameter parameter = new CustomParameter();
                Annotation[] parameterAnnotations = methodParameter.getParameterAnnotations();
                Arrays.stream(parameterAnnotations).forEach(annotation -> {
                    if (annotation instanceof PathVariable) {
                        PathVariable pathVariable = (PathVariable) annotation;
                        mapping.getPathVariables()
                                .add(new CustomPathVariable(pathVariable.name(), pathVariable.required()));
                    } else if (annotation instanceof RequestParam) {
                        RequestParam requestParam = (RequestParam) annotation;
                        parameter.setName(requestParam.name());
                        String defaultValue = requestParam.defaultValue();
                        if (!defaultValue.equals(ValueConstants.DEFAULT_NONE)) {
                            parameter.setDefaultValue(defaultValue);
                        }
                        parameter.setRequired(requestParam.required());
                        parameter.setType(methodParameter.getParameter().getType().getSimpleName());
                        mapping.getParams().add(parameter);
                    }
                });
            });
            mappings.add(mapping);
        }

        ((SimpleUrlHandlerMapping) viewControllerHandlerMapping).getHandlerMap().forEach((s, o) -> {
            CustomMapping mapping = new CustomMapping();
            mapping.setMethods(Collections.singleton("GET"));
            mapping.setPatterns(Collections.singleton(s));
            mappings.add(mapping);
        });

        mappings.sort(Comparator.comparing(o -> o.getPatterns().stream().findFirst().orElse("")));
        log.info(new ObjectMapper().writeValueAsString(mappings));
    }

    /**
     * Custom mapping class.
     */
    @JsonInclude(JsonInclude.Include.NON_EMPTY)
    @Data
    public class CustomMapping {
        private Set<String> patterns;
        private Set<String> methods;
        private List<CustomParameter> params = new ArrayList<>();
        private List<CustomPathVariable> pathVariables = new ArrayList<>();
    }

    /**
     * Custom Parameter class
     */
    @JsonInclude(JsonInclude.Include.NON_NULL)
    @Data
    public class CustomParameter {
        private String name;
        private String type;
        private String defaultValue;
        private Boolean required;
    }

    /**
     * Custom path variable class.
     */
    @JsonInclude(JsonInclude.Include.NON_NULL)
    @AllArgsConstructor
    @Data
    public class CustomPathVariable {
        private String name;
        private Boolean required;
    }
}