initBinder method is not being called for conversion from String to Enum

Question

I'm testing out the @InitBinder annotation so I can have String objects converted into appropriate Enum objects during web requests.

I created the following simple Enum :

SampleEnum.java

public enum SampleEnum {
    ONE,
    TWO,
    THREE,
    FOUR,
    FIVE;
}

Then, I created an editor extending PropertyEditorSupport to be called from the @InitBinder code:

EnumPropertyEditor.java

@SuppressWarnings("rawtypes")
public class EnumPropertyEditor extends PropertyEditorSupport {
    private Class clazz;

    public EnumPropertyEditor(Class clazz) {
        this.clazz = clazz;
    }

    @Override
    public String getAsText() {
        return (getValue() == null ? "" : ((Enum) getValue()).name());
    }

    @SuppressWarnings("unchecked")
    @Override
    public void setAsText(String text) {
        Enum e = Enum.valueOf(clazz, text);
        setValue(e);
    }
}

Then, in my controller I added the @InitBinder and a simple request mapping:

Controller

@InitBinder
public void initBinder(WebDataBinder binder) {
    binder.registerCustomEditor(SampleEnum.class, new EnumPropertyEditor(SampleEnum.class));
}

@RequestMapping(method = POST, value = "/postSampleEnum")
@ResponseBody
public SampleEnum postSampleEnum(@RequestBody SampleEnum sampleEnum) {
    return sampleEnum;  
}

From my understanding, a request for this controller method should attempt to convert a string value into the SampleEnum object. However, no breakpoints are hit in either initBinder , request mapping method, nor any of the methods in the EnumPropertyEditor .

I'm testing with RESTClient in FireFox, and have tried sending in the request body "THREE", which I would expect to work. Instead, I get a 415 error regardless of the what's in the request body. (The server refused this request because the request entity is in a format not supported by the requested resource for the requested method ().)

If I change the request mapping to take in a string instead of a SampleEnum , the postSampleEnum gets called and doesn't use the custom editor (as expected).

Am I missing anything that allows the custom editor code to be called? What is the best way to continue debugging this?

Answer 1

First of all, I forgot to add the application/json content-type to the request header in RESTClient. >_<

However, I noticed that the code execution still doesn't go through the custom property editor. As GriffeyDog said, it looks like the code only executes if I switch to a RequestParam or ModelAttribute .