Getting Started with RequestFactory - Google Web Toolkit - Google Code - 0 views
-
Entity Proxies
-
anonymous on 10 Jan 11Proxy type (on the Client) vs Entity type (on the server)
-
-
proxy types
-
entity types
- ...147 more annotations...
-
methods that return service stubs
-
one RequestFactory interface for your application
-
employeeRequest();
-
@Service(Employee.class)
-
extends RequestContext
-
extends RequestFactory
-
service stub
-
RequestFactory service stubs
-
must extend RequestContext
-
The methods in a service stub do not return entities directly
-
return subclasses of com.google.gwt.requestfactory.shared.Request.
-
This allows the methods on the interface to be invoked asynchronously with
-
Request.fire()
-
fire( new Receiver()
-
onSuccess
-
callers pass an AsyncCallback that implements onSuccess()
-
takes a Receiver which must implement onSuccess()
-
Receiver is an abstract class having a default implementation of onFailure()
-
you can extend Receiver and override onFailure()
-
onViolation()
-
any constraint violations on the server
-
The Request type returned from each method
-
parameterized with the return type of the service method.
-
Methods that have no return value should return type Request<Void>
-
BigDecimal, BigInteger, Boolean, Byte, Enum, Character, Date, Double, Float, Integer, Long, Short, String, Void
-
subclass of EntityProxy
-
List<T> or Set<T>
-
primitive types are not supported
-
methods that operate on an entity itself
-
like persist() and remove()
-
return objects of type InstanceRequest rather than Reques
-
Server Implementations
-
methods defined in an
-
entity's service interface
-
implemented in the class named
-
@Service annotation
-
in these examples, is the entity class
-
service implementations do not directly implement the RequestContext interface
-
server-side implementations use the domain entity types
-
@Entity
-
EntityManager
-
createQuery
-
getResultList();
-
entityManager()
-
createEntityManager()
-
em.persist(this);
-
em.remove(attached
-
em.close();
-
defined in the service's
-
RequestContext interface
-
even though the implementation does not formally implement the interface in Java
-
name and argument list for each method
-
same on client and server
-
Client side methods
-
return Request<T>
-
only T on the server
-
EntityProxy types become the domain entity type on the server
-
Methods that return a Request object in the client interface are implemented as static methods on the entity
-
Methods that operate on a single instance of an entity, like persist() and remove(),
-
eturn an
-
InstanceRequest
-
in the client interface
-
Instance methods do not pass the instance directly, but rather via the
-
using()
-
instance methods must be implemented as non-static methods in the entity type
-
Four special methods are required on all entities
-
as they are used by the RequestFactory servlet:
-
constructor
-
findEntity
-
An entity's getId()
-
is typically auto-generated by the persistence engine (JDO, JPA, Objectify, etc.)
-
"find by ID" method has a special naming convention
-
find()
-
"find" plus the type's simple name
-
On the server
-
getVersion() method is used by RequestFactory to infer if an entity has changed
-
backing store (JDO, JPA, etc.) is responsible for updating the version each time the object is persisted,
-
RequestFactoryServlet sends an UPDATE
-
if an entity changes as
-
Second, the client maintains a version cache of recently seen entities
-
Whenever it sees an entity whose version has changed, it fires
-
UPDATE events on the event bus
-
so that listeners can update the view
-
GWT.create
-
and initialize it with your application's EventBus
-
GWT.create
-
requestFactory.initialize
-
create a new entity on the client
-
EmployeeRequest request
-
EmployeeProxy newEmployee
-
All client-side code should use the EmployeeProxy
-
not the Employee entity itself
-
unlike GWT-RPC, where the same concrete type is used on both client and server
-
RequestFactory
-
designed to be used with an ORM layer like JDO or JPA
-
on the server
-
to build data-oriented (CRUD) apps with an ORM-like interface
-
on the client
-
easy to implement a data access layer
-
structure your server-side code in a data-centric way
-
GWT-RPC, which is service-oriented
-
On the client side, RequestFactory keeps track of objects that have been modified and sends only changes
-
lightweight network payloads
-
solid foundation for automatic batching and caching of requests in the future
-
RequestFactoryServlet
-
RequestFactory uses its own servlet
-
own protocol
-
not designed for general purpose services like GWT-RPC
-
implements its
-
It is designed specifically for implementing a persistence layer on both client and server.
-
In persistence frameworks like JDO and JPA, entities are annotated with
-
client-side representation of an entity
-
known as a
-
DTO (Data Transfer Object)
-
hook used to indicate that an object can be managed by RequestFactory
-
RequestFactory
-
EntityProxy interface
-
automatically populates bean-style properties between entities on the server and the corresponding EntityProxy on the client,
-
send only changes ("deltas") to the server
-
extends EntityProxy
-
interface
-
@ProxyFor
-
reference the server-side entity being represented
-
It is not necessary to represent every property and method from the server-side entity in the EntityProxy
-
EntityProxyId returned by this method is used throughout RequestFactory-related classes
-
while getId() is shown in this example, most client code will want to refer to
-
EntityProxy.stableId() i
-
to represent any type
-
is not required to expose an ID and version
-
often used to represent embedded object types within entities
-
@Embedded
-
Address
-
Address type
-
POJO with no persistence annotations
-
Address is represented as a ValueProxy
-
extends ValueProxy
-
interface
-
extends EntityProxy
-
interface
-
AddressProxy
-
AddressProxy
-
ValueProxy can be used to pass any type to and from the server
-
RequestFactory
-
interface between your client and server code
-
RequestContext interface
-
The server-side service
-
must implement each method
Cached
