Java Code Examples for com.google.cloud.datastore.Query#newGqlQueryBuilder()

@Override
public List<String> getKinds(boolean excludeSystemKinds) {
  try {
    String query = "SELECT __key__ FROM " + ENTITY_KINDS + " ORDER BY __key__";
    GqlQuery.Builder<Key> gqlQueryBuilder = Query.newGqlQueryBuilder(ResultType.KEY, query);
    gqlQueryBuilder.setNamespace(entityManager.getEffectiveNamespace());
    GqlQuery<Key> gqlQuery = gqlQueryBuilder.build();
    QueryResults<Key> results = entityManager.getDatastore().run(gqlQuery);
    List<String> kinds = new ArrayList<>(50);
    while (results.hasNext()) {
      Key key = results.next();
      String kind = key.getName();
      if (excludeSystemKinds && kind.startsWith("__")) {
        continue;
      }
      kinds.add(key.getName());
    }
    return kinds;
  } catch (DatastoreException exp) {
    throw new EntityManagerException(exp);
  }
}
 

@Override
public QueryResponse<String> getNamespaces(DatastoreCursor fromCursor, int limit) {
  try {
    String query = "SELECT __key__ FROM " + ENTITY_NAMESPACES + " ORDER BY __key__";
    if (limit > 0) {
      query += " LIMIT @Limit";
    }
    query += " OFFSET @Offset";
    GqlQuery.Builder<Key> gqlQueryBuilder = Query.newGqlQueryBuilder(ResultType.KEY, query);
    if (limit > 0) {
      gqlQueryBuilder.setBinding("Limit", limit);
    }
    gqlQueryBuilder.setBinding("Offset", Cursor.fromUrlSafe(fromCursor.getEncoded()));
    GqlQuery<Key> gqlQuery = gqlQueryBuilder.build();
    Datastore datastore = entityManager.getDatastore();
    QueryResults<Key> results = datastore.run(gqlQuery);
    DefaultQueryResponse<String> response = new DefaultQueryResponse<>();
    List<String> namespaces = new ArrayList<>(Math.max(limit, 50));
    response.setStartCursor(new DefaultDatastoreCursor(results.getCursorAfter().toUrlSafe()));
    while (results.hasNext()) {
      Key key = results.next();
      String name = key.getName();
      namespaces.add(name == null ? "" : name);
    }
    response.setResults(namespaces);
    response.setEndCursor(new DefaultDatastoreCursor(results.getCursorAfter().toUrlSafe()));
    return response;
  } catch (DatastoreException exp) {
    throw new EntityManagerException(exp);
  }
}
 

/**
 * Executes the given {@link EntityQueryRequest} and returns the response.
 * 
 * @param expectedResultType
 *          the expected type of results.
 * @param request
 *          the entity query request
 * @return the query response
 */
public <E> QueryResponse<E> executeEntityQueryRequest(Class<E> expectedResultType,
    EntityQueryRequest request) {
  try {
    GqlQuery.Builder<Entity> queryBuilder = Query.newGqlQueryBuilder(ResultType.ENTITY,
        request.getQuery());
    queryBuilder.setNamespace(entityManager.getEffectiveNamespace());
    queryBuilder.setAllowLiteral(request.isAllowLiterals());
    QueryUtils.applyNamedBindings(queryBuilder, request.getNamedBindings());
    QueryUtils.applyPositionalBindings(queryBuilder, request.getPositionalBindings());
    GqlQuery<Entity> gqlQuery = queryBuilder.build();
    QueryResults<Entity> results = nativeReader.run(gqlQuery);
    List<E> entities = new ArrayList<>();
    DefaultQueryResponse<E> response = new DefaultQueryResponse<>();
    response.setStartCursor(new DefaultDatastoreCursor(results.getCursorAfter().toUrlSafe()));
    while (results.hasNext()) {
      Entity result = results.next();
      E entity = Unmarshaller.unmarshal(result, expectedResultType);
      entities.add(entity);
    }
    response.setResults(entities);
    response.setEndCursor(new DefaultDatastoreCursor(results.getCursorAfter().toUrlSafe()));
    response.setQueryResponseMetadata(
        new DefaultQueryResponseMetadata(
            QueryResponseMetadata.QueryState.forMoreResultsType(results.getMoreResults())));
    entityManager.executeEntityListeners(CallbackType.POST_LOAD, entities);
    return response;
  } catch (DatastoreException exp) {
    throw new EntityManagerException(exp);
  }
}
 

/**
 * Executes the given {@link ProjectionQueryRequest} and returns the response.
 * 
 * @param expectedResultType
 *          the expected type of results.
 * @param request
 *          the projection query request
 * @return the query response
 */
public <E> QueryResponse<E> executeProjectionQueryRequest(Class<E> expectedResultType,
    ProjectionQueryRequest request) {
  try {
    GqlQuery.Builder<ProjectionEntity> queryBuilder = Query
        .newGqlQueryBuilder(ResultType.PROJECTION_ENTITY, request.getQuery());
    queryBuilder.setNamespace(entityManager.getEffectiveNamespace());
    queryBuilder.setAllowLiteral(request.isAllowLiterals());
    QueryUtils.applyNamedBindings(queryBuilder, request.getNamedBindings());
    QueryUtils.applyPositionalBindings(queryBuilder, request.getPositionalBindings());
    GqlQuery<ProjectionEntity> gqlQuery = queryBuilder.build();
    QueryResults<ProjectionEntity> results = nativeReader.run(gqlQuery);
    List<E> entities = new ArrayList<>();
    DefaultQueryResponse<E> response = new DefaultQueryResponse<>();
    response.setStartCursor(new DefaultDatastoreCursor(results.getCursorAfter().toUrlSafe()));
    while (results.hasNext()) {
      ProjectionEntity result = results.next();
      E entity = Unmarshaller.unmarshal(result, expectedResultType);
      entities.add(entity);
    }
    response.setResults(entities);
    response.setEndCursor(new DefaultDatastoreCursor(results.getCursorAfter().toUrlSafe()));
    response.setQueryResponseMetadata(
        new DefaultQueryResponseMetadata(
            QueryResponseMetadata.QueryState.forMoreResultsType(results.getMoreResults())));
    // TODO should we invoke PostLoad callback for projected entities?
    return response;
  } catch (DatastoreException exp) {
    throw new EntityManagerException(exp);
  }
}
 

/**
 * Executes the given {@link KeyQueryRequest} and returns the response.
 * 
 * @param request
 *          the key query request
 * @return the query response
 */
public QueryResponse<DatastoreKey> executeKeyQueryRequest(KeyQueryRequest request) {
  try {
    GqlQuery.Builder<Key> queryBuilder = Query.newGqlQueryBuilder(ResultType.KEY,
        request.getQuery());
    queryBuilder.setNamespace(entityManager.getEffectiveNamespace());
    queryBuilder.setAllowLiteral(request.isAllowLiterals());
    QueryUtils.applyNamedBindings(queryBuilder, request.getNamedBindings());
    QueryUtils.applyPositionalBindings(queryBuilder, request.getPositionalBindings());
    GqlQuery<Key> gqlQuery = queryBuilder.build();
    QueryResults<Key> results = nativeReader.run(gqlQuery);
    List<DatastoreKey> entities = new ArrayList<>();
    DefaultQueryResponse<DatastoreKey> response = new DefaultQueryResponse<>();
    response.setStartCursor(new DefaultDatastoreCursor(results.getCursorAfter().toUrlSafe()));
    while (results.hasNext()) {
      Key result = results.next();
      DatastoreKey datastoreKey = new DefaultDatastoreKey(result);
      entities.add(datastoreKey);
    }
    response.setResults(entities);
    response.setEndCursor(new DefaultDatastoreCursor(results.getCursorAfter().toUrlSafe()));
    response.setQueryResponseMetadata(
        new DefaultQueryResponseMetadata(
            QueryResponseMetadata.QueryState.forMoreResultsType(results.getMoreResults())));
    return response;
  } catch (DatastoreException exp) {
    throw new EntityManagerException(exp);
  }
}