Examples with Query com.google.appengine.api.datastore.Query used on opensource projects

Example 61 with Query

use of com.google.appengine.api.datastore.Query in project java-docs-samples by GoogleCloudPlatform.

the class GuestbookTestUtilities method cleanDatastore.

public static void cleanDatastore(DatastoreService ds, String book) {
    Query query = new Query("Greeting").setAncestor(new KeyFactory.Builder("Guestbook", book).getKey()).setKeysOnly();
    PreparedQuery pq = ds.prepare(query);
    List<Entity> entities = pq.asList(FetchOptions.Builder.withDefaults());
    ArrayList<Key> keys = new ArrayList<>(entities.size());
    for (Entity e : entities) {
        keys.add(e.getKey());
    }
    ds.delete(keys);
}

Example 62 with Query

use of com.google.appengine.api.datastore.Query in project java-docs-samples by GoogleCloudPlatform.

the class StatsServlet method doGet.

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    // [START stat_example]
    DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
    Entity globalStat = datastore.prepare(new Query("__Stat_Total__")).asSingleEntity();
    Long totalBytes = (Long) globalStat.getProperty("bytes");
    Long totalEntities = (Long) globalStat.getProperty("count");
    // [END stat_example]
    resp.setContentType("text/plain");
    resp.setCharacterEncoding("UTF-8");
    PrintWriter w = resp.getWriter();
    w.printf("%d bytes\n%d entities\n", totalBytes, totalEntities);
}

Example 63 with Query

use of com.google.appengine.api.datastore.Query in project java-docs-samples by GoogleCloudPlatform.

the class GuestbookStrong method listGreetingEntities.

@Override
protected List<Entity> listGreetingEntities(DatastoreService datastore) {
    Key guestbookKey = KeyFactory.createKey("Guestbook", guestbookName);
    Query query = new Query("Greeting", guestbookKey).setAncestor(guestbookKey).addSort("date", Query.SortDirection.DESCENDING);
    return datastore.prepare(query).asList(FetchOptions.Builder.withLimit(10));
}

Example 64 with Query

use of com.google.appengine.api.datastore.Query in project java-docs-samples by GoogleCloudPlatform.

the class LocalHighRepDatastoreTest method testEventuallyConsistentGlobalQueryResult.

@Test
public void testEventuallyConsistentGlobalQueryResult() {
    DatastoreService ds = DatastoreServiceFactory.getDatastoreService();
    Key ancestor = KeyFactory.createKey("foo", 3);
    ds.put(new Entity("yam", ancestor));
    ds.put(new Entity("yam", ancestor));
    // Global query doesn't see the data.
    assertEquals(0, ds.prepare(new Query("yam")).countEntities(withLimit(10)));
    // Ancestor query does see the data.
    assertEquals(2, ds.prepare(new Query("yam", ancestor)).countEntities(withLimit(10)));
}

Example 65 with Query

use of com.google.appengine.api.datastore.Query in project CodeU-Spring-2018 by maksymko.

the class PersistentDataStore method loadMessages.

/**
 * Loads all Message objects from the Datastore service and returns them in a List.
 *
 * @throws PersistentDataStoreException if an error was detected during the load from the
 *     Datastore service
 */
public List<Message> loadMessages() throws PersistentDataStoreException {
    List<Message> messages = new ArrayList<>();
    // Retrieve all messages from the datastore.
    Query query = new Query("chat-messages");
    PreparedQuery results = datastore.prepare(query);
    for (Entity entity : results.asIterable()) {
        try {
            UUID uuid = UUID.fromString((String) entity.getProperty("uuid"));
            UUID conversationUuid = UUID.fromString((String) entity.getProperty("conv_uuid"));
            UUID authorUuid = UUID.fromString((String) entity.getProperty("author_uuid"));
            Instant creationTime = Instant.parse((String) entity.getProperty("creation_time"));
            String content = (String) entity.getProperty("content");
            Message message = new Message(uuid, conversationUuid, authorUuid, content, creationTime);
            messages.add(message);
        } catch (Exception e) {
            // database entity definition mismatches, or service mismatches.
            throw new PersistentDataStoreException(e);
        }
    }
    return messages;
}