Java QueryResultIterator类代码示例

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
/**
 * Delete all entities in batches of {@value BATCH_SIZE}.
 *
 * @return number of entities deleted
 */
public long deleteAll() {
    Query<E> query = ofy().load().type(entityType).limit(BATCH_SIZE);
    QueryResultIterator<Key<E>> iterator = query.keys().iterator();
    List<Key<E>> keysToDelete = new ArrayList<>();
    long numDeleted = 0;
    while (iterator.hasNext()) {
        Key<E> key = iterator.next();
        keysToDelete.add(key);
        if (!iterator.hasNext()) {
            deleteByKey(fromKeys.from(keysToDelete));
            numDeleted += keysToDelete.size();
            keysToDelete.clear();
            iterator = query.startAt(iterator.getCursor()).keys().iterator();
        }
    }
    return numDeleted;
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
/**
 * List all entities.
 *
 * @param cursor used for pagination to determine which page to return
 * @param limit  the maximum number of entries to return
 * @return a response that encapsulates the result list and the next page token/cursor
 */
@ApiMethod(
        name = "list",
        path = "user",
        httpMethod = ApiMethod.HttpMethod.GET)
public CollectionResponse<User> list(@Nullable @Named("cursor") String cursor, @Nullable @Named("limit") Integer limit) {
    limit = limit == null ? DEFAULT_LIST_LIMIT : limit;
    Query<User> query = ofy().load().type(User.class).limit(limit);
    if (cursor != null) {
        query = query.startAt(Cursor.fromWebSafeString(cursor));
    }
    QueryResultIterator<User> queryIterator = query.iterator();
    List<User> userList = new ArrayList<User>(limit);
    while (queryIterator.hasNext()) {
        userList.add(queryIterator.next());
    }
    return CollectionResponse.<User>builder().setItems(userList).setNextPageToken(queryIterator.getCursor().toWebSafeString()).build();
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
/**
 * List all entities.
 *
 * @param cursor used for pagination to determine which page to return
 * @param limit  the maximum number of entries to return
 * @return a response that encapsulates the result list and the next page token/cursor
 */
@ApiMethod(
        name = "list",
        path = "joke",
        httpMethod = ApiMethod.HttpMethod.GET)
public CollectionResponse<Joke> list(@Nullable @Named("cursor") String cursor, @Nullable @Named("limit") Integer limit) {
    Integer limitParam = limit == null ? DEFAULT_LIST_LIMIT : limit;
    Query<Joke> query = ofy().load().type(Joke.class).limit(limitParam);
    if (cursor != null) {
        query = query.startAt(Cursor.fromWebSafeString(cursor));
    }
    QueryResultIterator<Joke> queryIterator = query.iterator();
    List<Joke> jokeList = new ArrayList<>(limitParam);
    while (queryIterator.hasNext()) {
        jokeList.add(queryIterator.next());
    }
    return CollectionResponse.<Joke>builder().setItems(jokeList).setNextPageToken(queryIterator.getCursor().toWebSafeString()).build();
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
/**
 * List all entities.
 *
 * @param cursor used for pagination to determine which page to return
 * @param limit  the maximum number of entries to return
 * @return a response that encapsulates the result list and the next page token/cursor
 */
@ApiMethod(
        name = "list",
        path = "orders",
        httpMethod = ApiMethod.HttpMethod.GET)
public CollectionResponse<Orders> list(@Nullable @Named("cursor") String cursor, @Nullable @Named("limit") Integer limit) {
    limit = limit == null ? DEFAULT_LIST_LIMIT : limit;
    Query<Orders> query = ofy().load().type(Orders.class).limit(limit);
    if (cursor != null) {
        query = query.startAt(Cursor.fromWebSafeString(cursor));
    }
    QueryResultIterator<Orders> queryIterator = query.iterator();
    List<Orders> ordersList = new ArrayList<Orders>(limit);
    while (queryIterator.hasNext()) {
        ordersList.add(queryIterator.next());
    }
    return CollectionResponse.<Orders>builder().setItems(ordersList).setNextPageToken(queryIterator.getCursor().toWebSafeString()).build();
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
/**
 * List all entities.
 *
 * @param cursor used for pagination to determine which page to return
 * @param limit  the maximum number of entries to return
 * @return a response that encapsulates the result list and the next page token/cursor
 */
@ApiMethod(
        name = "list",
        path = "users",
        httpMethod = ApiMethod.HttpMethod.GET)
public CollectionResponse<Users> list(@Nullable @Named("cursor") String cursor, @Nullable @Named("limit") Integer limit) {
    limit = limit == null ? DEFAULT_LIST_LIMIT : limit;
    Query<Users> query = ofy().load().type(Users.class).limit(limit);
    if (cursor != null) {
        query = query.startAt(Cursor.fromWebSafeString(cursor));
    }
    QueryResultIterator<Users> queryIterator = query.iterator();
    List<Users> usersList = new ArrayList<Users>(limit);
    while (queryIterator.hasNext()) {
        usersList.add(queryIterator.next());
    }
    return CollectionResponse.<Users>builder().setItems(usersList).setNextPageToken(queryIterator.getCursor().toWebSafeString()).build();
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
@Override
public Result<Book> listBooks(String startCursorString) {
  FetchOptions fetchOptions = FetchOptions.Builder.withLimit(10); // Only show 10 at a time
  if (startCursorString != null && !startCursorString.equals("")) {
    fetchOptions.startCursor(Cursor.fromWebSafeString(startCursorString)); // Where we left off
  }
  Query query = new Query(BOOK_KIND) // We only care about Books
      .addSort(Book.TITLE, SortDirection.ASCENDING); // Use default Index "title"
  PreparedQuery preparedQuery = datastore.prepare(query);
  QueryResultIterator<Entity> results = preparedQuery.asQueryResultIterator(fetchOptions);

  List<Book> resultBooks = entitiesToBooks(results);     // Retrieve and convert Entities
  Cursor cursor = results.getCursor();              // Where to start next time
  if (cursor != null && resultBooks.size() == 10) {         // Are we paging? Save Cursor
    String cursorString = cursor.toWebSafeString();               // Cursors are WebSafe
    return new Result<>(resultBooks, cursorString);
  } else {
    return new Result<>(resultBooks);
  }
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
@Override
public Result<Book> listBooksByUser(String userId, String startCursorString) {
  FetchOptions fetchOptions = FetchOptions.Builder.withLimit(10); // Only show 10 at a time
  if (startCursorString != null && !startCursorString.equals("")) {
    fetchOptions.startCursor(Cursor.fromWebSafeString(startCursorString)); // Where we left off
  }
  Query query = new Query(BOOK_KIND) // We only care about Books
      // Only for this user
      .setFilter(new Query.FilterPredicate(
          Book.CREATED_BY_ID, Query.FilterOperator.EQUAL, userId))
      // a custom datastore index is required since you are filtering by one property
      // but ordering by another
      .addSort(Book.TITLE, SortDirection.ASCENDING);
  PreparedQuery preparedQuery = datastore.prepare(query);
  QueryResultIterator<Entity> results = preparedQuery.asQueryResultIterator(fetchOptions);

  List<Book> resultBooks = entitiesToBooks(results);     // Retrieve and convert Entities
  Cursor cursor = results.getCursor();              // Where to start next time
  if (cursor != null && resultBooks.size() == 10) {         // Are we paging? Save Cursor
    String cursorString = cursor.toWebSafeString();               // Cursors are WebSafe
    return new Result<>(resultBooks, cursorString);
  } else {
    return new Result<>(resultBooks);
  }
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
/**
 * Convenience method to get all objects matching a single property
 * 
 * @param propName
 * @param propValue
 * @return T matching Object
 * @throws TooManyResultsException
 */
public T getByProperty(String propName, Object propValue)
		throws TooManyResultsException
{
       QueryResultIterator<T> fetch = ofy().load().type(clazz)
               .filter(propName, propValue)
               .limit(2).iterator();
       if (!fetch.hasNext())
	{
		return null;
	}
	T obj = fetch.next();
	if (fetch.hasNext())
	{
		throw new TooManyResultsException(fetch.toString()
				+ " returned too many results");
	}
	return obj;
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
public static String getPseudoFromJid(String p_jid)
{
  if( p_jid == null )
  {
    return "???";
  }
  String jid = p_jid.split("/")[0];
  Query<EbAccount> query = dao().query( EbAccount.class ).filter( "m_jabberId", jid );
  QueryResultIterator<EbAccount> it = query.iterator();
  if( !it.hasNext() )
  {
    // we could remove the end of jid @...
    // but in this case someone can use a jid in the form of <existingPseudo>@anydomain
    // to fool players !
    return jid;
  }
  return it.next().getPseudo();
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
@Test
public void testCursor() throws Exception {
    Entity parent = createTestEntityWithUniqueMethodNameKey("Person", "testKeysOnly");
    Key key = parent.getKey();

    Entity john = createEntity("Person", key)
        .withProperty("name", "John")
        .withProperty("surname", "Doe")
        .store();

    Query query = new Query("Person")
        .setAncestor(key)
        .setKeysOnly();

    PreparedQuery preparedQuery = service.prepare(query);
    QueryResultIterator<Entity> iter = preparedQuery.asQueryResultIterator();
    Assert.assertNotNull(iter.next());
    Cursor cursor = iter.getCursor();

    iter = service.prepare(query).asQueryResultIterator(FetchOptions.Builder.withStartCursor(cursor));
    Assert.assertFalse(iter.hasNext());
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
@Test
public void testIndexListFromIterator() throws Exception {
    Entity parent = createTestEntityWithUniqueMethodNameKey("Person", "testKeysOnly");
    Key key = parent.getKey();

    Entity tom = createEntity("Person", key)
        .withProperty("name", "Tom")
        .withProperty("surname", "Foe")
        .store();

    Query query = new Query("Person")
        .setAncestor(key)
        .setKeysOnly();

    PreparedQuery preparedQuery = service.prepare(query);
    QueryResultIterator<Entity> iter = preparedQuery.asQueryResultIterator();
    List<Index> indexes = iter.getIndexList();
    if (indexes != null) {
        // TODO -- something useful
        System.out.println("indexes = " + indexes);
    }
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
public void run(long cutOffTimeMillis) {
    int updatedProfileCount = 0;
    QueryResultIterator<VolunteerProfile> profileIterator = VolunteerProfile.withExpiredAppointments(
            cutOffTimeMillis, CHUNK_SIZE);
    List<VolunteerProfile> updatedProfiles = new ArrayList<VolunteerProfile>(CHUNK_SIZE);

    while (profileIterator.hasNext() && hasTimeRemaining()) {
        for (int i = 0; i < CHUNK_SIZE && profileIterator.hasNext(); i++) {
            VolunteerProfile nextProfile = profileIterator.next();
            nextProfile.removeExpiredAppointments(cutOffTimeMillis);

            updatedProfiles.add(nextProfile);
            updatedProfileCount++;
        }

        OfyService.ofy().put(updatedProfiles);
        updatedProfiles.clear();
    }

    logger.info(String.format("Updated schedules for %d profiles", updatedProfileCount));

    if (profileIterator.hasNext()) {
        isTerminatedEarly = true;
        logger.warning("Terminating early due to request timeout");
    }
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
@Test
public void testFindingVolunteerWithOldAppointment() {
    localServiceTestHelper.setUp();

    VolunteerProfile volunteerProfile = new VolunteerProfile();
    volunteerProfile.setUserId("1");

    DateTime startTime = dateTime("2013-06-01T20:00:00-03:00");
    DateTime endTime = dateTime("2013-06-01T20:30:00-03:00");
    DateTime cutoffTime = dateTime("2013-06-02T00:00:00-03:00");

    volunteerProfile.addAppointmentTime(getRideRequest(), startTime, endTime);
    Objectify ofy = OfyService.ofy();
    ofy.put(volunteerProfile);

    QueryResultIterator<VolunteerProfile> volunteerProfileIterator = VolunteerProfile
            .withExpiredAppointments(cutoffTime.getMillis(), 100);
    List<VolunteerProfile> volunteerProfiles = CollectionUtils.listOfIterator(volunteerProfileIterator);

    assertEquals(Arrays.asList(volunteerProfile), volunteerProfiles);

    localServiceTestHelper.tearDown();
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
@Test
public void testFindingVolunteerWithoutOldAppointments() {
    localServiceTestHelper.setUp();

    VolunteerProfile volunteerProfile = new VolunteerProfile();
    volunteerProfile.setUserId("1");

    DateTime startTime = dateTime("2013-06-01T20:00:00-03:00");
    DateTime endTime = dateTime("2013-06-01T20:30:00-03:00");
    DateTime cutoffTime = dateTime("2013-05-30T00:00:00-03:00");

    volunteerProfile.addAppointmentTime(getRideRequest(), startTime, endTime);
    Objectify ofy = OfyService.ofy();
    ofy.put(volunteerProfile);

    QueryResultIterator<VolunteerProfile> volunteerProfileIterator = VolunteerProfile
            .withExpiredAppointments(cutoffTime.getMillis(), 100);
    List<VolunteerProfile> volunteerProfiles = CollectionUtils.listOfIterator(volunteerProfileIterator);

    assertTrue(volunteerProfiles.isEmpty());

    localServiceTestHelper.tearDown();
}
 

import com.google.appengine.api.datastore.QueryResultIterator; //导入依赖的package包/类
public List<E> listAllForQuery(Query<E> query) {
    QueryResultIterator<E> iterator = query.iterator();
    List<E> entities = new ArrayList<>();
    while (iterator.hasNext()) {
        entities.add(iterator.next());
        if (!iterator.hasNext()) {
            iterator = query.startAt(iterator.getCursor()).iterator();
        }
    }
    return entities;
}