Question

I’m encountering the following problem – I have simple GWT overlay types, and I’m trying to convert one to a JSON string on the client; I’m simply doing:

new JSONObject(this).toString();

The conversion works, but it adds an additional, incorrect key to the json string, such as:

{"key1":"value1", "key2":value2, "$H":1}

where “$H”:1 doesn’t correspond to anything in my overlay type.
Any idea why this is?

Any help is appreciated on this, thanks.

Answer 1

This issue is define in this link

The $H property comes from the
implementation of
JavaScriptObject#hashCode() (in
com.google.gwt.cire.client.impl.Impl#getHashCode(Object)).

In your case, this is due to
AbstractEditableCell maintaining a map
of value keys to their “view data”,
and your use (I guess) of the default
ProvidesKey implementation
(SimpleProvidesKey) which directly
returns the item.

So, when rendering, the EditTextCell
calls getViewData, which looks up the
key in the map (and thus needs the
hashcode of the key, hence the call to
hashCode), and the key is your JSO
(hence the new $H property).

I believe that giving a ProvidesKey
implementation (in you case, returning
the name property for instance) to the
Celltable would solve your issue.