Question

I’m building a REST application with AppEngine Datastore as persistence layer. However I have a problem using the com.google.appengine.api.datastore.Key within my Resource Class when parsing they key to create a new entry.

Error message is following:
SEVERE: Missing dependency for method public com.acolsolutions.loyaltycard.persistence.entities.Card com.acolsolutions.loyaltycard.resources.CardResource.findByKey(com.google.appengine.api.datastore.Key) at parameter at index 0
SEVERE: Method, public com.acolsolutions.loyaltycard.persistence.entities.Card com.acolsolutions.loyaltycard.resources.CardResource.findByKey(com.google.appengine.api.dat astore.Key), annotated with GET of resource, class com.acolsolutions.loyaltycard.resources.CardResource, is not recognized as valid resource method.

It seems like the problem happens here. Seems that the value cant get converted in to a Key type:

    public Card findByKey(@PathParam("key") Key key) {
    ...
    }

My REST class looks as follows:
import java.util.List;

import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

import com.acolsolutions.loyaltycard.dataobjects.CardDAO;
import com.acolsolutions.loyaltycard.persistence.entities.Card;
import com.google.appengine.api.datastore.Key;

@Path("/cards")
public class CardResource {
CardDAO dao = new CardDAO();

@GET
@Produces({ MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML })
public List<Card> findAll() {
    System.out.println("findAll");
    return dao.findAll("creationDate desc");
}

@GET
@Path("search/{query}")
@Produces({ MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML })
public List<Card> findByName(@PathParam("query") String query) {
    System.out.println("findByName: " + query);
    return dao.findByName(query, "creationDate desc");
}


@GET
@Path("{key}")
@Produces({ MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML })
public Card findByKey(@PathParam("key") Key key) {
    //System.out.println("findByKey " + key.toString());
    return dao.findByKey(key);
}

Can somebody tell me what I have to do to get this working?

Thanks,
Chris

Answer 1

You can try changing the parameter to String instead of Key and then use com.google.appengine.api.datastore.KeyFactory.stringToKey(String stringKey) to get the Key.