Spring Data Rest: ResourceProcessor configuration is not working properly - spring

Question

I have a strange behaviour with a Spring Data Rest implementation (version 2.5.2.RELEASE).
I'm trying to register a #Bean of ResourceProcessor<Resource<Entity>>, but there is something strange.
I'm trying with two kinds of solutions:
1) Declaring the #Bean in a class:
#Bean
public ResourceProcessor<Resource<Author>> authorProcessor() {
return new ResourceProcessor<Resource<Author>>() {
#Override
public Resource<Author> process(Resource<Author> resource) {
System.out.println("method process of bean ResourceProcessor of class RepositoryBaseConfiguration");
return resource;
}
};
}
2) Implementing the interface ResourceProcessor:
#Component
public class AuthorResourceProcessor implements ResourceProcessor<Resource<Author>> {
#Override
public Resource<Author> process(Resource<Author> resource) {
System.out.println("method process of class AuthorResourceProcessor");
return resource;
}
}
The processors are completely ignored: the message is never printed.
I noticed that the class org.springframework.data.rest.webmvc.ResourceProcessorInvoker has a constructor:
public ResourceProcessorInvoker(Collection<ResourceProcessor<?>> processors) {
//...
}
This constructor is invoked 2 times at the start of the application instead of only one time (as I will expect), and I don't understand why.
The first time, the "processors" variable is solved with the two beans (as expected) and with the bean org.springframework.data.rest.webmvc.ProfileResourceProcessor.
But the second time, the "processors" variable is solved with only the bean org.springframework.data.rest.webmvc.ProfileResourceProcessor.
The second configuration #Override the first one.
Any idea?

Answer 1

The problem depends on the configurations loaded at the startup of the application.
I had this configuration on the web.xml:
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring/spring-web-config.xml</param-value>
</context-param>
<servlet>
<servlet-name>rest</servlet-name>
<servlet-class>org.springframework.data.rest.webmvc.RepositoryRestDispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
So, the ContextLoaderListener loaded the correct configuration in the first time; the "load-on-startup" property of the servlet "RepositoryRestDispatcherServlet" launch a second context configuration load.
I also had a custom class that extended org.springframework.data.rest.webmvc.config.RepositoryRestMvcConfiguration, but this custom class was ignored by the moment that the constructor of RepositoryRestDispatcherServlet load the default RepositoryRestMvcConfiguration, causing the lost of the configurations.
To solve that issue I have created a custom RepositoryRestDispatcherServlet in this way:
public class AppRepositoryRestDispatcherServlet extends DispatcherServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
public AppRepositoryRestDispatcherServlet() {
configure();
}
public AppRepositoryRestDispatcherServlet(WebApplicationContext webApplicationContext) {
super(webApplicationContext);
configure();
}
private void configure() {
setContextClass(AnnotationConfigWebApplicationContext.class);
setContextConfigLocation(RepositoryBaseConfiguration.class.getName());
}
}
The class is the same as RepositoryRestDispatcherServlet, with the only difference that in the setContextConfigLocation is passed the custom class that extends RepositoryRestMvcConfiguration (RepositoryBaseConfiguration in this example).
Obviously I had to update the web.xml as follows:
<servlet>
<servlet-name>rest</servlet-name>
<servlet-class>my.package.AppRepositoryRestDispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
In this way, the configuration is correctly loaded and mantained.