On Apr 3, 2009, at 2:45 AM, Farrukh Najmi wrote:
>>>> On Apr 1, 2009, at 4:45 PM, Farrukh Najmi wrote:
>>>>
>>>>
>>>>> OK so my code now looks like this:
>>>>>
>>>>> List<String> postalAddresses = ...
>>>>> for (String postalAddressStr : postalAddresses) {
>>>>> MessageBodyReader r =
>>>>> providers.getMessageBodyReader(PostalAddressType.class,
>>>>> PostalAddressType.class, new Annotation[1],
>>>>> MediaType.APPLICATION_JSON_TYPE);
>>>>> PostalAddressType postalAddress =
>>>>> (PostalAddressType) r.readFrom(PostalAddressType.class,
>>>>> PostalAddressType.class, new Annotation[1],
>>>>> MediaType.APPLICATION_JSON_TYPE,
>>>>> new InBoundHeaders(),
>>>>> new
>>>>> ByteArrayInputStream(postalAddressStr.getBytes()));
>>>>> org.getPostalAddress().add(postalAddress);
>>>>> }
>
> Hi Guys,
>
> I am now cleaning up my code and trying to write a utility generic
> class that converts from List<String> of JSON String to List<T>
> where T represent the type of my JAXB bean. I am close and the class
> looks like this:
>
> public class JSONToJAXBConvertor<T> {
>
> /**
> * Convert a List of JSON String intoa List of corresponding
> JAXB beans.
> *
> * @param formParamsMulti the form parameters
> * @param formParam the name of a specific form parameter
> whose value is a List<String> where each String is a JSON String
> * @return the List of JAXB beans that have been unmarshalled
> from List of JSON Strings
> * @throws java.io.IOException
> */
> public List<T> convertJSONToJAXB(MultivaluedMap<String,
> String> formParamsMulti, String formParam) throws IOException {
> List<T> jaxbObjects = new ArrayList<T>();
>
> List<String> jsonStrings =
> getListValueFromMultiValuedMap(formParamsMulti, formParam);
> for (String jsonString : jsonStrings) {
> MessageBodyReader r =
> providers.getMessageBodyReader(PostalAddressType.class,
> PostalAddressType.class, new Annotation[1],
> MediaType.APPLICATION_JSON_TYPE);
> T jaxbObject = (T)
> r.readFrom(PostalAddressType.class, PostalAddressType.class, new
> Annotation[1], MediaType.APPLICATION_JSON_TYPE,
> new InBoundHeaders(),
> new ByteArrayInputStream(jsonString.getBytes()));
> jaxbObjects.add(jaxbObject);
> }
> return jaxbObjects;
> }
> }
>
> Assume T above is PostalAddressType. What I can't figure out is how
> to replace PostalAddressType.class using generics code and Type T.
> Replacing it with T.class is not legal. Perhaps I need to do
> something with jaxbObjects?
>
> So if "List<T> jaxbObjects" is really "List<PostalAddressType>
> jaxbObjects" how can I get the class for PostalAddressType?
>
For the convertJSONToJAXB include a parameter "Class<T> c". It sucks i
know, buy that is because Generics was bashed into a language that was
not originally designed for it :-(
The other alternative is to instantiate concreate anonymous inner
classes of JSONToJAXBConvertor from which the class of the type can be
obtained. But that is more complicated for some users/implementors.
Some more points:
- you only need to obtain the MessageBodyReader once outside the for
loop, because T is the same for each
String.
- you are creating an instance of Annotation[1], you need to do
Annotation[0]. If you like create a static empty array
and reuse that.
Paul.