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for Java developers, there is a remote API handler available; adding following to your web xml file should work (disclaimer: I have not yet personally tested this.) <servlet>   <servlet-name>remoteapi</servlet-name>   <servlet-class>com.google.apphosting.utils.remoteapi.RemoteApiServlet</servlet-class> </servlet> <servlet-mapping>   <servlet-name>remoteapi</servlet-name>   <url-pattern>/remote_api</url-pattern> </servlet-mapping> <security-constraint>   <web-resource-collection>     <web-resource-name>remoteapi</web-resource-name>     <url-pattern>/remote_api</url-pattern>   </web-resource-collection>   <auth-constraint>     <role-name>admin</role-name>   </auth-constraint> </security-constraint>

If using the datastore API directly, a common pattern of usage is: // Get a handle on the datastore itself DatastoreService datastore = DatastoreServiceFactory.getDatastoreService(); // Lookup data by known key name Entity userEntity = datastore.get(KeyFactory.createKey("UserInfo", email)); // Or perform a query Query query = new Query("Task", userEntity); query.addFilter("dueDate", Query.FilterOperator.LESS_THAN, today); for (Entity taskEntity : datastore.prepare(query).asIterable()) { if ("done".equals(taskEntity.getProperty("status"))) { datastore.delete(taskEntity); } else { taskEntity.setProperty("status", "overdue"); datastore.put(taskEntity); } }

One common pattern when using the Task Queue API is known as 'task chaining'. You execute a task on the task queue, and at some point, determine that you're going to need another task, either to complete the work the current task is doing, or to start doing something new.

The solution is straightforward: use task names. Task names ensure that the chained task is only enqueued once, even if the task doing the chaining gets re-executed repeatedly. There are many ways to derive a task name;

If you want to see this in practice, the bulkupdate library makes use of this pattern, constructing task names from the datastore ID of the bulkupdate job (to ensure uniqueness) and the number of the chained task (to ensure consistency).

You don't have to add each class individually to the black list. They are all regex patterns, so just do this: <extend-configuration-property name="rpc.blacklist" value="com.google.gwt.user.client.ui.*Collection"/> In my case I wanted even finer grained control over which collections get included, so I did this: <extend-configuration-property name="rpc.blacklist" value="-.*List"/> <extend-configuration-property name="rpc.blacklist" value="-.*Map"/> <extend-configuration-property name="rpc.blacklist" value="-.*Collection"/> <extend-configuration-property name="rpc.blacklist" value="+java.util.HashMap"/> <extend-configuration-property name="rpc.blacklist" value="+java.util.LinkedHashMap"/> <extend-configuration-property name="rpc.blacklist" value="+java.util.ArrayList"/>

Please support the ability to server static files from the runtime based on regex patterns similar to the current Python runtime. Currently the only way to simulate this functionality is with a servlet. This is not ideal peformance, as evidenced by existing special handling of static files. The most compelling use case is for versioning static files with the app's version ID so that browsers can maximally cache static files without experiencing stale caches later when the app is updated.

From what I understand, you are "manually" copying the properties from the Entity to the DTO. But this process is automated in GWT 2.1 So, I am not sending my entities directly, but the proxies as per the documentation : http://code.google.com/webtoolkit/doc/latest/DevGuideRequestFactory.html "An entity proxy is a client-side representation of an entity, otherwise known as a DTO (Data Transfer Object). With RequestFactory, entity proxies are interfaces that extend the EntityProxy interface, which is the hook used to indicate that an object can be managed by RequestFactory. RequestFactory automatically populates bean-style properties between entities on the server and the corresponding EntityProxy on the client, which simplifies using the DTO pattern. Furthermore, the EntityProxy interface enables RequestFactory to compute and send only changes ("deltas") to the server." "Entity proxies simply extend the EntityProxy interface and use the @ProxyFor annotation to 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, only getters and setters for properties that should be exposed to the client." The entity proxies are merely interfaces that are being populated by the new GWT 2.1 RequestFactory framework. I have no control over this copying process. Per definition, getters/setters of the real entity are injected into the EntityProxy whenever they are present; So my problem still stands : what about complex values like com.google.appengine.api.datastore.Email that are not known by the client side code ? How to transfer these complex values to the client.

When I copy my entities onto my dtos, some entity fields don't even make it into the dto. Others only have getters in the dto because they are read-only to the client. Those that do get into the dto get converted to native Java types. For instance, Text gets converted to String. Key gets encoded to a url friendly string. If I have Set fields on the entities to manager my relations (property lists), I remap those to ArrayList... First, don't serialize interfaces to GWT client, you'll get Javascript bloat. Then, Hashmap is costly to serialize because String.hashCode() is not the same on in Java and in Javascript. Hence, all the items need to be re-inserted into a client side map. Of course, in Web mode, performance is good enough... but in development mode, your data transfers will become really slow for somewhat big transfers.