CategoriesResource.java

package ejava.examples.ejbwar.inventory.rs;

import javax.inject.Inject;
import javax.ws.rs.DELETE;
import javax.ws.rs.DefaultValue;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Request;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.UriInfo;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import ejava.examples.ejbwar.inventory.bo.Categories;
import ejava.examples.ejbwar.inventory.bo.Category;
import ejava.examples.ejbwar.inventory.ejb.InventoryMgmtEJB;

/**
 * This class implements a web facade for the product catageories in the 
 * inventory management. It uses JAX-RS to implement the server-side HTTP
 * communications.
 */
@Path("categories") //part of the method's final URI
public class CategoriesResource {
    private static final Logger log = LoggerFactory.getLogger(CategoriesResource.class);
    
    @Inject
    private InventoryMgmtEJB ejb;
    @Context
    private Request request;
    @Context 
    private UriInfo uriInfo;
    
    /**
     * This method will respond to a GET of the base resource URI to 
     * return categories based on query parameters.
     * @param name
     * @param offset
     * @param limit
     * @return
     */
    @GET @Path("")
    @Produces({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
    public Response findCategoriesByName(
            @QueryParam("name") @DefaultValue("") String name,
            @QueryParam("offset") @DefaultValue("0") int offset,
            @QueryParam("limit") @DefaultValue("0") int limit) {
        log.debug(String.format("%s %s", request.getMethod(), uriInfo.getAbsolutePath()));

        try {
            Categories categories = ejb.findCategoryByName(name, offset, limit);
                //wrap java.lang.List in object that preserves type for marshalling
            return Response.ok(categories)
                    .build();
        } catch (Exception ex) {
            return ResourceHelper.serverError(log, "get categories", ex).build();
        }
    }
    
    /**
     * This method will respond to a GET method for (root)/{id} URIs to get 
     * a specific category.
     *  
     * @param id
     * @return
     */
    @GET @Path("{id}")
    @Produces({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
    public Response getCategory(@PathParam("id")int id) {
        log.debug(String.format("%s %s", request.getMethod(), uriInfo.getAbsolutePath()));

        try {
            Category category = ejb.getCategory(id);
            if (category != null) {
                return Response.ok(category)
                        .tag("" + category.getVersion())
                        .build();
            }
            else {
                return Response.status(Response.Status.NOT_FOUND)
                        .entity(String.format("unable to locate category %d", id))
                        .type(MediaType.TEXT_PLAIN)
                        .build();
            }
        } catch (Exception ex) {
            return ResourceHelper.serverError(log, "get category", ex).build();
        }
    }

    /**
     * This method responds to DELETE method calls to (root)/{id} URIs to
     * delete a specific category.
     * @param id
     * @return
     */
    @DELETE @Path("{id}")
    public Response deleteCategory(@PathParam("id")int id) {
        log.debug(String.format("%s %s", request.getMethod(), uriInfo.getAbsolutePath()));

        try {
            ejb.deleteCategory(id);
            return Response.noContent().build();
        } catch (Exception ex) {
            return ResourceHelper.serverError(log, "delete category", ex).build();
        }
    }

}