Become a Java EE developer - Part III Models.java

Become a Java EE developer - Part III Models.java

package com.autodesk.adn.viewanddata.api;

import java.util.Collection;
import java.util.HashMap;
import java.util.UUID;
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.Response;
import org.json.JSONException;
import com.google.gson.Gson;

@Path("/models")
public class Models {

	//JSON Parser
	private Gson _gson = new Gson();

	static class Model{

		public String name;
		public String urn;
		public String id;

		public Model(
				String _id, 
				String _name, 
				String _urn) {

			name = _name;
			urn = _urn;
			id = _id;
		}
	}

	static HashMap<String, Model> _modelsDb = null;

	static void initialize() {

		_modelsDb = new HashMap<String, Model>();

		String id1 = UUID.randomUUID().toString();
		String id2 = UUID.randomUUID().toString();
		String id3 = UUID.randomUUID().toString();

		_modelsDb.put(id1, 
				new Model(
						id1,		
						"Engine", 
						"... base 64 URN ..."));

		_modelsDb.put(id2, 
				new Model(
						id2,
						"Hairdryer", 
						"... base 64 URN ..."));

		_modelsDb.put(id3, 
				new Model(
						id3,		
						"Plane Engine", 
						"... base 64 URN ..."));
	}

	public Models() {

		if(Models._modelsDb == null) {
			Models.initialize();
		}
	}

	//GET /models/{modelId}
	@GET
	@Produces("application/json")
	public Response getModels() throws JSONException {

		Collection<Model> models = _modelsDb.values();  

		String result = _gson.toJson(models);

		return Response.status(200).entity(result).build();
	}

	// GET /models/{modelId}
	@GET
	@Path("{modelId}")
	@Produces("application/json")
	public Response getModelById(@PathParam("modelId") String modelId) throws JSONException {

		if(!_modelsDb.containsKey(modelId)) {

			//NOT FOUND 404
			return Response.status(404).entity("NOT FOUND").build();
		}

		String result = _gson.toJson(_modelsDb.get(modelId));

		return Response.status(200).entity(result).build();
	}

	// POST /models
	@POST
	@Produces("application/json")
	public Response addNewModel(String payload) throws JSONException {

		Model model = _gson.fromJson(payload, Model.class); 

		model.id = UUID.randomUUID().toString();

		_modelsDb.put(model.id, model);

		String result = _gson.toJson(model);

		return Response.status(200).entity(result).build();
	}

	// PUT /models/{modelId}
	@PUT
	@Path("{modelId}")
	@Produces("application/json")
	public Response updateModel(@PathParam("modelId") String modelId, String payload) throws JSONException {

		if(!_modelsDb.containsKey(modelId)) {

			//NOT FOUND 404
			return Response.status(404).entity("NOT FOUND").build();
		}

		Model model = _gson.fromJson(payload, Model.class); 

		model.id = modelId;

		_modelsDb.put(modelId, model);

		String result = _gson.toJson(model);

		return Response.status(200).entity(result).build();
	}

	// DELETE /models/{modelId}
	@DELETE
	@Path("{modelId}")
	@Produces("application/json")
	public Response deleteModel(@PathParam("modelId") String modelId) throws JSONException {

		if(!_modelsDb.containsKey(modelId)) {

			//NOT FOUND 404
			return Response.status(404).entity("NOT FOUND").build();
		}

		Model model = _modelsDb.get(modelId);

		_modelsDb.remove(modelId);

		String result = _gson.toJson(model);

		return Response.status(200).entity(result).build();
	}
}