![String data = contact.getName();
data += "," + contact.getYearOfBirth();
String[] parts = data.split(",");
contact.setName(parts[0]);
contact.setYearOfBirth(Integer.parseInt(parts[1]));
String conversion
lördag 24 januari 15](https://image.slidesharecdn.com/comparinggwttransportmechanisms-150124011420-conversion-gate02/85/Comparing-GWT-Transport-Mechanisms-8-320.jpg)
![String data = contact.getName();
data += "," + contact.getYearOfBirth();
String[] parts = data.split(",");
contact.setName(parts[0]);
contact.setYearOfBirth(Integer.parseInt(parts[1]));
String conversion
lördag 24 januari 15](https://image.slidesharecdn.com/comparinggwttransportmechanisms-150124011420-conversion-gate02/85/Comparing-GWT-Transport-Mechanisms-9-320.jpg)
![{
name: "John Doe",
yearOfBirth: 1900,
address: {
street: "Happy Street 1",
city: "Turku"
},
emailAddresses: ["john@doe.com", "johndoe@gmail.com"]
}
JSON
lördag 24 januari 15](https://image.slidesharecdn.com/comparinggwttransportmechanisms-150124011420-conversion-gate02/85/Comparing-GWT-Transport-Mechanisms-10-320.jpg)
Comparing GWT Transport Mechanisms
- 1. Leif Åstrand Product Manager Comparing GWT Transport Mechanisms lördag 24 januari 15
- 3. RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, url); try { builder.sendRequest(requestDataString, new RequestCallback() { @Override public void onResponseReceived(Request request, Response response) { int statusCode = response.getStatusCode(); String text = response.getText(); } @Override public void onError(Request request, Throwable exception) { // TODO Handle asynchronous problems } }); } catch (RequestException e) { // TODO Handle synchronous problems } RequestBuilder lördag 24 januari 15
- 4. Good • It just works Bad • Low level RequestBuilder lördag 24 januari 15
- 5. Real world usage 8 % lördag 24 januari 15
- 6. What to send? lördag 24 januari 15
- 7. public class Contact { private String name; private int yearOfBirth; private List<String> emailAddresses; private Address address; public static class Address { private String street; private String city; } // + Getters and setters } Contact lördag 24 januari 15
- 8. String data = contact.getName(); data += "," + contact.getYearOfBirth(); String[] parts = data.split(","); contact.setName(parts[0]); contact.setYearOfBirth(Integer.parseInt(parts[1])); String conversion lördag 24 januari 15
- 9. String data = contact.getName(); data += "," + contact.getYearOfBirth(); String[] parts = data.split(","); contact.setName(parts[0]); contact.setYearOfBirth(Integer.parseInt(parts[1])); String conversion lördag 24 januari 15
- 10. { name: "John Doe", yearOfBirth: 1900, address: { street: "Happy Street 1", city: "Turku" }, emailAddresses: ["john@doe.com", "johndoe@gmail.com"] } JSON lördag 24 januari 15
- 11. JSONObject json = JSONParser.parseStrict(string).isObject(); contact.setName(json.get("name").isString().stringValue()); contact.setYearOfBirth( (int) json.get("yearOfBirth").isNumber().doubleValue()); contact.setAddress( parseAddress(json.get("address").isObject())); JSONArray emailAddresses = json.get("emailAddresses").isArray(); for (int i = 0; i < emailAddresses.size(); i++) { contact.getEmailAddresses().add( emailAddresses.get(i).isString().stringValue()); } } JSONValue parsing lördag 24 januari 15
- 12. Good • It’s standard • Human readable format • Compact format Bad • Not completely typesafe • Boilerplate • Client only JSONValue lördag 24 januari 15
- 13. What about the server? lördag 24 januari 15
- 14. ObjectMapper mapper = new ObjectMapper(); try { Contact contact = mapper.readValue(string, Contact.class); } catch (VariousExceptions e) { // Do something sensible } Jackson on the server lördag 24 januari 15
- 15. Reflection Code generation lördag 24 januari 15
- 16. public static interface ContactMapper extends ObjectMapper<Contact> {} public Contact parseContact(String string) { ContactMapper mapper = GWT.create(ContactMapper.class); Contact contact = mapper.read(jsonString); return contact; } gwt-jackson lördag 24 januari 15
- 17. Good • Minimal boiler plate • Can share code between server and client Bad • Only creating and reading strings Jackson lördag 24 januari 15
- 18. Where to send? lördag 24 januari 15
- 19. public interface ContactService { public void saveContact(Contact contact); public List<Contact> getContacts(); } Remote Procedure Call lördag 24 januari 15
- 20. public interface ContactService { public AsyncResult<Void> saveContact(Contact contact); public AsyncResult<List<Contact>> getContacts(); } Asynchronous public interface ContactServiceAsync { public void saveContact(Contact contact, AsyncCallback<Void> callback); public void getContacts(AsyncCallback<List<Contact>> callback); } lördag 24 januari 15
- 21. Good • Simple but powerful concept • The default solution • Optimized format Bad • Sending the entire object graph • Polymorphism can cause huge files • Optimized format GWT-RPC lördag 24 januari 15
- 22. Most popular! 51 % lördag 24 januari 15
- 23. Where to send JSON? lördag 24 januari 15
- 24. GET /contacts DELETE /contacts/5 PUT /contacts { name: "John Doe", ... } REST lördag 24 januari 15
- 25. @Path("/contacts") public interface ContactsService { @GET public List<Contact> listContacts(); @Path("/{id}") @DELETE public void deleteContact(@PathParam("id") int id); @PUT public void createContact(Contact contact); } JAX-RS lördag 24 januari 15
- 26. @Path("/contacts") public interface ContactsService extends DirectRestService { // Same content } ContactsService contactsService = GWT.create(ContactsService.class); REST.withCallback(myContactListCallback). call(contactsService).listContacts(); resty-gwt lördag 24 januari 15
- 27. Good • Any server • Any client Bad • Some boilerplate resty-gwt lördag 24 januari 15
- 28. Real world usage 6 % lördag 24 januari 15
- 29. Wild ideas lördag 24 januari 15
- 30. Send interfaces instead of objects lördag 24 januari 15
- 31. public interface Contact { public void setName(String name); public String getName(); public void setYearOfBirth(int yearOfBirth); public int getYearOfBirth(); public void setAddress(Address address); public Address getAddress(); public void setEmailAddresses(List<String> addresses); public List<String> getEmailAddresses(); } Contact interface lördag 24 januari 15
- 32. New possibilities Send partial updates Manage entity identity Use instance methods for RPC lördag 24 januari 15
- 33. Good • Entities do not need to be GWT compatible • Combines RPC and entity management • Automatic request handling Bad • Complex setup • Heavy coupling with the server RequestFactory lördag 24 januari 15
- 34. Define message Generate code lördag 24 januari 15
- 35. message Contact { required string name = 1; required int32 yearOfBirth = 2; repeated string emailAddresses = 3; optional Address address = 4; } Contact message lördag 24 januari 15
- 36. Good • Any language • Google's data interchange format • Backwards compatible Bad • Binary format • Not very widely used Protocol Buffers lördag 24 januari 15
- 37. What if we put the server in control? lördag 24 januari 15
- 38. lördag 24 januari 15
- 39. public class ContactState extends SharedState { public String name; @DelegateToWidget public int yearOfBirth; } @OnStateChange("name") private void updateName() { doSomethingWithTheName(getState().name); } @Override protected ContactState getState() { return (ContactState) super.getState(); } State synchronization lördag 24 januari 15
- 40. public interface ContactRpc extends ServerRpc { public void deleteContact(int id); } // Register RPC handler on the server registerRpc(new ContactRpc() { @Override public void deleteContact(int id) { ContactDAO.deleteById(id); } }); // Send RPC from the client public void sendDelete(int contactId) { getRpcProxy(ContactRpc.class).deleteContact(contactId); } RPC lördag 24 januari 15
- 41. Good • Stateful server • Server push Bad • Stateful server • Tied to the framework Vaadin Connectors lördag 24 januari 15
- 42. What if we completely hide the transport? lördag 24 januari 15
- 43. // Fire event @Inject Event<Contact> contactEvent; public void updateContact(Contact contact) { contactEvent.fire(contact); } // Listen to event public void contactUpdateObserver(@Observes Contact contact) { ContactDAO.updateContact(contact); } CDI events lördag 24 januari 15
- 44. Good • Transparent communication • Server push Bad • Transparent communication • Tied to the framework Errai Bus lördag 24 januari 15
- 45. Questions? Answers? Please rate the talk at gwtcreate.com/agenda ? leif@vaadin.com lördag 24 januari 15