Main > 1.0.8 > Examples > Simple field filter

Dynamic filter

Using this type of filters you can create your own filter with custom behaviour. All dynamic filters should implement DynamicFilterEvent.class also filter should be annotated by DynamicFilterComponent annotation.

Next example illustrates typical implementation

    @DynamicFilterComponent
    public class DemoIdFilter implements DynamicFilterEvent {
        @Override
        public FilterFields onGetFilterFields(MethodParameter methodParameter, RequestSession request) {

            if(request.getSession().getAttribute("SOME_VALUE") != null) {
                return new FilterFields(User.class, Arrays.asList("id", "password", "email"));
            } else
                return new FilterFields();
        }
    }

In this example we created DemoIdFilter which attempts to find attribute SOME_VALUE in Http Session. If attribute exists event onGetFilterFields returns configured FilterFields. As you can see, FilterFields contains filter for User.class If Response Body of Spring Service contains object with class name User.class it will be filtered and fields “id”, “password”, “email” will be removed from response.

Where

• DynamicFilterComponent annotation indicates that DemoIdFilter is dynamic filter. Also it indicates that this class is Spring Component. It means this class will be instantiated by Spring Bean Processor. Therefore you can autowire other components of your project.

• Also filter implements DynamicFilterEvent. And you should to implement your logic in onGetFilterFields event.

• onGetFilterFields should to return FilterFields object.

Using dynamic filter

So, we created DemoIdFilter and let’s see how we can use it. Next example illustrates typical usage of filter

    @DynamicFilter(DemoIdFilter.class)
    @RequestMapping(value = "/users/signIn",
            params = {"email", "password"}, method = RequestMethod.POST,
            consumes = {MediaType.APPLICATION_FORM_URLENCODED_VALUE},
            produces = {MediaType.APPLICATION_JSON_VALUE})            
    public User signIn(@RequestParam("email") String email, @RequestParam("password") String password) {
        return userController.signInUser(email, password);
    }    

With this filter you get huge space of Service Response customization.