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

Example 6 with FetchOptions

use of com.google.appengine.api.datastore.FetchOptions in project siena by mandubian.

the class GaePersistenceManager method doFetchIterable.

private <T> Iterable<T> doFetchIterable(Query<T> query, int limit, int offset) {
    QueryOptionGaeContext gaeCtx = (QueryOptionGaeContext) query.option(QueryOptionGaeContext.ID);
    QueryOptionState state = (QueryOptionState) query.option(QueryOptionState.ID);
    QueryOptionFetchType fetchType = (QueryOptionFetchType) query.option(QueryOptionFetchType.ID);
    if (gaeCtx == null) {
        gaeCtx = new QueryOptionGaeContext();
        query.customize(gaeCtx);
    }
    FetchOptions fetchOptions = FetchOptions.Builder.withDefaults();
    QueryOptionPage pag = (QueryOptionPage) query.option(QueryOptionPage.ID);
    if (!pag.isPaginating()) {
        // no pagination but pageOption active
        if (pag.isActive()) {
            // if local limit is set, it overrides the pageOption.pageSize
            if (limit != Integer.MAX_VALUE) {
                gaeCtx.realPageSize = limit;
                fetchOptions.limit(gaeCtx.realPageSize);
                // pageOption is passivated to be sure it is not reused
                pag.passivate();
            } else // using pageOption.pageSize
            {
                gaeCtx.realPageSize = pag.pageSize;
                fetchOptions.limit(gaeCtx.realPageSize);
                // passivates the pageOption in stateless mode not to keep anything between 2 requests
                if (state.isStateless()) {
                    pag.passivate();
                }
            }
        } else {
            if (limit != Integer.MAX_VALUE) {
                gaeCtx.realPageSize = limit;
                fetchOptions.limit(gaeCtx.realPageSize);
            }
        }
    } else {
        // paginating so use the pagesize and don't passivate pageOption
        // local limit is not taken into account
        gaeCtx.realPageSize = pag.pageSize;
        fetchOptions.limit(gaeCtx.realPageSize);
    }
    QueryOptionOffset off = (QueryOptionOffset) query.option(QueryOptionOffset.ID);
    // if local offset has been set, uses it
    if (offset != 0) {
        off.activate();
        off.offset = offset;
    }
    // if previousPage has detected there is no more data, simply returns an empty list
    if (gaeCtx.noMoreDataBefore) {
        return new ArrayList<T>();
    }
    if (state.isStateless()) {
        if (pag.isPaginating()) {
            if (off.isActive()) {
                gaeCtx.realOffset += off.offset;
                fetchOptions.offset(gaeCtx.realOffset);
                off.passivate();
            } else {
                fetchOptions.offset(gaeCtx.realOffset);
            }
        } else {
            // if stateless and not paginating, resets the realoffset to 0
            gaeCtx.realOffset = off.offset;
            if (off.isActive()) {
                fetchOptions.offset(gaeCtx.realOffset);
                off.passivate();
            }
        }
        switch(fetchType.fetchType) {
            case ITER:
            default:
                {
                    // uses iterable as it is the only async request for prepared query for the time being
                    Iterable<Entity> entities = prepare(query).asIterable(fetchOptions);
                    return new GaeSienaIterable<T>(this, entities, query);
                }
        }
    } else {
        if (off.isActive()) {
            // by default, we add the offset but it can be added with the realoffset
            // in case of cursor desactivated
            fetchOptions.offset(off.offset);
            gaeCtx.realOffset += off.offset;
            off.passivate();
        }
        // manages cursor limitations for IN and != operators
        if (!gaeCtx.isActive()) {
            // cursor not yet created
            switch(fetchType.fetchType) {
                case ITER:
                default:
                    {
                        PreparedQuery pq = prepare(query);
                        if (pag.isPaginating()) {
                            // in case of pagination, we need to allow asynchronous calls such as:
                            // QueryAsync<MyClass> query = pm.createQuery(MyClass).paginate(5).stateful().order("name");
                            // SienaFuture<Iterable<MyClass>> future1 = query.iter();
                            // SienaFuture<Iterable<MyClass>> future2 = query.nextPage().iter();
                            // Iterable<MyClass> it = future1.get().iterator();
                            // while(it.hasNext()) { // do it }
                            // it = future2.get().iterator();
                            // while(it.hasNext()) { // do it }
                            // so we can't use the asQueryResultIterable as the cursor is not moved to the end of the current page
                            // but moved at each call of iterable.iterator().next()
                            // thus we use the List in this case to be able to move directly to the next page with cursors
                            QueryResultList<Entity> entities = pq.asQueryResultList(fetchOptions);
                            // activates the GaeCtx now that it is initialised
                            gaeCtx.activate();
                            // sets the current cursor (in stateful mode, cursor is always kept for further use)
                            // if(gaeCtx.useCursor){
                            Cursor cursor = entities.getCursor();
                            if (cursor != null) {
                                gaeCtx.addCursor(cursor.toWebSafeString());
                            }
                            // }
                            return new GaeSienaIterable<T>(this, entities, query);
                        } else {
                            // if not paginating, we simply use the queryresultiterable and moves the current cursor
                            // while iterating
                            QueryResultIterable<Entity> entities = pq.asQueryResultIterable(fetchOptions);
                            // activates the GaeCtx now that it is initialised
                            gaeCtx.activate();
                            return new GaeSienaIterableWithCursor<T>(this, entities, query);
                        }
                    }
            }
        } else {
            switch(fetchType.fetchType) {
                case ITER:
                default:
                    {
                        PreparedQuery pq = prepare(query);
                        if (pag.isPaginating()) {
                            // in case of pagination, we need to allow asynchronous calls such as:
                            // QueryAsync<MyClass> query = pm.createQuery(MyClass).paginate(5).stateful().order("name");
                            // SienaFuture<Iterable<MyClass>> future1 = query.iter();
                            // SienaFuture<Iterable<MyClass>> future2 = query.nextPage().iter();
                            // Iterable<MyClass> it = future1.get().iterator();
                            // while(it.hasNext()) { // do it }
                            // it = future2.get().iterator();
                            // while(it.hasNext()) { // do it }
                            // so we can't use the asQueryResultIterable as the cursor is not moved to the end of the current page
                            // but moved at each call of iterable.iterator().next()
                            // thus we use the List in this case to be able to move directly to the next page with cursors
                            QueryResultList<Entity> entities;
                            if (!gaeCtx.useCursor) {
                                // then uses offset (in case of IN or != operators)
                                // if(offset.isActive()){
                                // fetchOptions.offset(gaeCtx.realOffset);
                                // }
                                fetchOptions.offset(gaeCtx.realOffset);
                                entities = pq.asQueryResultList(fetchOptions);
                            } else {
                                String cursor = gaeCtx.currentCursor();
                                if (cursor != null) {
                                    entities = pq.asQueryResultList(fetchOptions.startCursor(Cursor.fromWebSafeString(cursor)));
                                } else {
                                    entities = pq.asQueryResultList(fetchOptions);
                                }
                                // sets the current cursor (in stateful mode, cursor is always kept for further use)
                                // if(gaeCtx.useCursor){
                                gaeCtx.addCursor(entities.getCursor().toWebSafeString());
                            // }
                            }
                            return new GaeSienaIterable<T>(this, entities, query);
                        } else {
                            // if not paginating, we simply use the queryresultiterable and moves the current cursor
                            // while iterating
                            QueryResultIterable<Entity> entities;
                            if (!gaeCtx.useCursor) {
                                // then uses offset (in case of IN or != operators)
                                // if(offset.isActive()){
                                // fetchOptions.offset(gaeCtx.realOffset);
                                // }
                                fetchOptions.offset(gaeCtx.realOffset);
                                entities = pq.asQueryResultIterable(fetchOptions);
                            } else {
                                String cursor = gaeCtx.currentCursor();
                                if (cursor != null) {
                                    entities = pq.asQueryResultIterable(fetchOptions.startCursor(Cursor.fromWebSafeString(gaeCtx.currentCursor())));
                                } else {
                                    entities = pq.asQueryResultIterable(fetchOptions);
                                }
                            }
                            return new GaeSienaIterableWithCursor<T>(this, entities, query);
                        }
                    }
            }
        }
    }
}

Example 7 with FetchOptions

use of com.google.appengine.api.datastore.FetchOptions in project siena by mandubian.

the class GaePersistenceManagerAsync method doFetchList.

private <T> SienaFuture<List<T>> doFetchList(QueryAsync<T> query, int limit, int offset) {
    QueryOptionGaeContext gaeCtx = (QueryOptionGaeContext) query.option(QueryOptionGaeContext.ID);
    if (gaeCtx == null) {
        gaeCtx = new QueryOptionGaeContext();
        query.customize(gaeCtx);
    }
    QueryOptionState state = (QueryOptionState) query.option(QueryOptionState.ID);
    QueryOptionFetchType fetchType = (QueryOptionFetchType) query.option(QueryOptionFetchType.ID);
    FetchOptions fetchOptions = FetchOptions.Builder.withDefaults();
    QueryOptionPage pag = (QueryOptionPage) query.option(QueryOptionPage.ID);
    if (!pag.isPaginating()) {
        // no pagination but pageOption active
        if (pag.isActive()) {
            // if local limit is set, it overrides the pageOption.pageSize
            if (limit != Integer.MAX_VALUE) {
                gaeCtx.realPageSize = limit;
                fetchOptions.limit(gaeCtx.realPageSize);
                // pageOption is passivated to be sure it is not reused
                pag.passivate();
            } else // using pageOption.pageSize
            {
                gaeCtx.realPageSize = pag.pageSize;
                fetchOptions.limit(gaeCtx.realPageSize);
                // passivates the pageOption in stateless mode not to keep anything between 2 requests
                if (state.isStateless()) {
                    pag.passivate();
                }
            }
        } else {
            if (limit != Integer.MAX_VALUE) {
                gaeCtx.realPageSize = limit;
                fetchOptions.limit(gaeCtx.realPageSize);
            }
        }
    } else {
        // paginating so use the pagesize and don't passivate pageOption
        // local limit is not taken into account
        gaeCtx.realPageSize = pag.pageSize;
        fetchOptions.limit(gaeCtx.realPageSize);
    }
    QueryOptionOffset off = (QueryOptionOffset) query.option(QueryOptionOffset.ID);
    // if local offset has been set, uses it
    if (offset != 0) {
        off.activate();
        off.offset = offset;
    }
    // if previousPage has detected there is no more data, simply returns an empty list
    if (gaeCtx.noMoreDataBefore) {
        return new SienaFutureMock<List<T>>(new ArrayList<T>());
    }
    if (state.isStateless()) {
        if (pag.isPaginating()) {
            if (off.isActive()) {
                gaeCtx.realOffset += off.offset;
                fetchOptions.offset(gaeCtx.realOffset);
                off.passivate();
            } else {
                fetchOptions.offset(gaeCtx.realOffset);
            }
        } else {
            // if stateless and not paginating, resets the realoffset to 0
            gaeCtx.realOffset = 0;
            if (off.isActive()) {
                gaeCtx.realOffset = off.offset;
                fetchOptions.offset(gaeCtx.realOffset);
                off.passivate();
            }
        }
        switch(fetchType.fetchType) {
            case KEYS_ONLY:
                {
                    // uses iterable as it is the only async request for prepared query for the time being
                    Iterable<Entity> entities = prepareKeysOnly(query).asIterable(fetchOptions);
                    return new GaeSienaFutureListMapper<T>(this, entities, query, GaeSienaFutureListMapper.MapType.KEYS_ONLY);
                }
            case NORMAL:
            default:
                {
                    // uses iterable as it is the only async request for prepared query for the time being
                    Iterable<Entity> entities = prepare(query).asIterable(fetchOptions);
                    return new GaeSienaFutureListMapper<T>(this, entities, query);
                }
        }
    } else {
        if (off.isActive()) {
            // by default, we add the offset but it can be added with the realoffset
            // in case of cursor desactivated
            fetchOptions.offset(off.offset);
            gaeCtx.realOffset += off.offset;
            off.passivate();
        }
        // manages cursor limitations for IN and != operators by using offset
        if (!gaeCtx.isActive()) {
            // cursor not yet created
            switch(fetchType.fetchType) {
                case KEYS_ONLY:
                    {
                        PreparedQuery pq = prepareKeysOnly(query);
                        if (!gaeCtx.useCursor) {
                            // then uses offset (in case of IN or != operators)
                            // if(offset.isActive()){
                            // fetchOptions.offset(offset.offset);
                            // }
                            fetchOptions.offset(gaeCtx.realOffset);
                        }
                        // we can't use real asynchronous function with cursors
                        // so the page is extracted at once and wrapped into a SienaFuture
                        QueryResultList<Entity> entities = pq.asQueryResultList(fetchOptions);
                        // activates the GaeCtx now that it is initialised
                        gaeCtx.activate();
                        // sets the current cursor (in stateful mode, cursor is always kept for further use)
                        if (pag.isPaginating()) {
                            Cursor cursor = entities.getCursor();
                            if (cursor != null) {
                                gaeCtx.addCursor(cursor.toWebSafeString());
                            }
                        } else {
                            Cursor cursor = entities.getCursor();
                            if (cursor != null) {
                                gaeCtx.addAndMoveCursor(entities.getCursor().toWebSafeString());
                            }
                            // keeps track of the offset anyway if not paginating
                            gaeCtx.realOffset += entities.size();
                        }
                        return new GaeSienaFutureListMapper<T>(this, entities, query, GaeSienaFutureListMapper.MapType.KEYS_ONLY);
                    }
                case NORMAL:
                default:
                    {
                        PreparedQuery pq = prepare(query);
                        if (!gaeCtx.useCursor) {
                            // then uses offset (in case of IN or != operators)
                            // if(offset.isActive()){
                            // fetchOptions.offset(offset.offset);
                            // }
                            fetchOptions.offset(gaeCtx.realOffset);
                        }
                        // we can't use real asynchronous function with cursors
                        // so the page is extracted at once and wrapped into a SienaFuture
                        QueryResultList<Entity> entities = pq.asQueryResultList(fetchOptions);
                        // activates the GaeCtx now that it is initialised
                        gaeCtx.activate();
                        // if(gaeCtx.useCursor){
                        if (pag.isPaginating()) {
                            Cursor cursor = entities.getCursor();
                            if (cursor != null) {
                                gaeCtx.addCursor(cursor.toWebSafeString());
                            }
                        } else {
                            Cursor cursor = entities.getCursor();
                            if (cursor != null) {
                                gaeCtx.addAndMoveCursor(entities.getCursor().toWebSafeString());
                            }
                            // keeps track of the offset anyway if not paginating
                            gaeCtx.realOffset += entities.size();
                        }
                        return new GaeSienaFutureListMapper<T>(this, entities, query);
                    }
            }
        } else {
            switch(fetchType.fetchType) {
                case KEYS_ONLY:
                    {
                        // we prepare the query each time
                        PreparedQuery pq = prepareKeysOnly(query);
                        QueryResultList<Entity> entities;
                        if (!gaeCtx.useCursor) {
                            // then uses offset (in case of IN or != operators)
                            // if(offset.isActive()){
                            // fetchOptions.offset(offset.offset);
                            // }
                            fetchOptions.offset(gaeCtx.realOffset);
                            // we can't use real asynchronous function with cursors
                            // so the page is extracted at once and wrapped into a SienaFuture
                            entities = pq.asQueryResultList(fetchOptions);
                        } else {
                            // we can't use real asynchronous function with cursors
                            // so the page is extracted at once and wrapped into a SienaFuture
                            String cursor = gaeCtx.currentCursor();
                            if (cursor != null) {
                                entities = pq.asQueryResultList(fetchOptions.startCursor(Cursor.fromWebSafeString(cursor)));
                            } else {
                                entities = pq.asQueryResultList(fetchOptions);
                            }
                        }
                        // if(gaeCtx.useCursor){
                        if (pag.isPaginating()) {
                            Cursor cursor = entities.getCursor();
                            if (cursor != null) {
                                gaeCtx.addCursor(cursor.toWebSafeString());
                            }
                        } else {
                            Cursor cursor = entities.getCursor();
                            if (cursor != null) {
                                gaeCtx.addAndMoveCursor(entities.getCursor().toWebSafeString());
                            }
                            // keeps track of the offset anyway if not paginating
                            gaeCtx.realOffset += entities.size();
                        }
                        return new GaeSienaFutureListMapper<T>(this, entities, query, GaeSienaFutureListMapper.MapType.KEYS_ONLY);
                    }
                case NORMAL:
                default:
                    {
                        PreparedQuery pq = prepare(query);
                        QueryResultList<Entity> entities;
                        if (!gaeCtx.useCursor) {
                            // then uses offset (in case of IN or != operators)
                            // if(offset.isActive()){
                            // fetchOptions.offset(offset.offset);
                            // }
                            fetchOptions.offset(gaeCtx.realOffset);
                            // we can't use real asynchronous function with cursors
                            // so the page is extracted at once and wrapped into a SienaFuture
                            entities = pq.asQueryResultList(fetchOptions);
                        } else {
                            // we can't use real asynchronous function with cursors
                            // so the page is extracted at once and wrapped into a SienaFuture
                            String cursor = gaeCtx.currentCursor();
                            if (cursor != null) {
                                entities = pq.asQueryResultList(fetchOptions.startCursor(Cursor.fromWebSafeString(gaeCtx.currentCursor())));
                            } else {
                                entities = pq.asQueryResultList(fetchOptions);
                            }
                        }
                        // if(gaeCtx.useCursor){
                        if (pag.isPaginating()) {
                            Cursor cursor = entities.getCursor();
                            if (cursor != null) {
                                gaeCtx.addCursor(cursor.toWebSafeString());
                            }
                        } else {
                            Cursor cursor = entities.getCursor();
                            if (cursor != null) {
                                gaeCtx.addAndMoveCursor(entities.getCursor().toWebSafeString());
                            }
                            // keeps track of the offset anyway
                            gaeCtx.realOffset += entities.size();
                        }
                        return new GaeSienaFutureListMapper<T>(this, entities, query);
                    }
            }
        }
    }
}

Example 8 with FetchOptions

use of com.google.appengine.api.datastore.FetchOptions in project getting-started-java by GoogleCloudPlatform.

the class DatastoreDao method listBooks.

// [END entitiesToBooks]
// [START listbooks]
@Override
public Result<Book> listBooks(String startCursorString) {
    // Only show 10 at a time
    FetchOptions fetchOptions = FetchOptions.Builder.withLimit(10);
    if (startCursorString != null && !startCursorString.equals("")) {
        // Where we left off
        fetchOptions.startCursor(Cursor.fromWebSafeString(startCursorString));
    }
    Query query = // We only care about Books
    new Query(BOOK_KIND).addSort(Book.TITLE, // Use default Index "title"
    SortDirection.ASCENDING);
    PreparedQuery preparedQuery = datastore.prepare(query);
    QueryResultIterator<Entity> results = preparedQuery.asQueryResultIterator(fetchOptions);
    // Retrieve and convert Entities
    List<Book> resultBooks = entitiesToBooks(results);
    // Where to start next time
    Cursor cursor = results.getCursor();
    if (cursor != null && resultBooks.size() == 10) {
        // Are we paging? Save Cursor
        // Cursors are WebSafe
        String cursorString = cursor.toWebSafeString();
        return new Result<>(resultBooks, cursorString);
    } else {
        return new Result<>(resultBooks);
    }
}

Example 9 with FetchOptions

use of com.google.appengine.api.datastore.FetchOptions in project Cached-Datastore by Emperorlou.

the class CachedDatastoreService method fetchKeys.

private List<Key> fetchKeys(Query q, int limit) {
    q.setKeysOnly();
    prepareQuery(q);
    int chunkSize = limit;
    FetchOptions fo = FetchOptions.Builder.withLimit(limit).chunkSize(chunkSize).prefetchSize(limit);
    List<Key> keys = new ArrayList<>();
    List<Entity> entities = pq.asList(fo);
    int count = entities.size();
    if (count > limit)
        count = limit;
    for (int i = 0; i < count; i++) {
        Entity e = entities.get(i);
        keys.add(e.getKey());
    }
    lastQuery_endCursor = null;
    if (statsTracking)
        incrementStat(QUERYKEYCACHE_QUERIES);
    return keys;
}

Example 10 with FetchOptions

use of com.google.appengine.api.datastore.FetchOptions in project getting-started-java by GoogleCloudPlatform.

the class DatastoreDao method listBooksByUser.

// [END listbooks]
// [START listbyuser]
@Override
public Result<Book> listBooksByUser(String userId, String startCursorString) {
    // Only show 10 at a time
    FetchOptions fetchOptions = FetchOptions.Builder.withLimit(10);
    if (startCursorString != null && !startCursorString.equals("")) {
        // Where we left off
        fetchOptions.startCursor(Cursor.fromWebSafeString(startCursorString));
    }
    Query query = // We only care about Books
    new Query(BOOK_KIND).setFilter(new Query.FilterPredicate(Book.CREATED_BY_ID, Query.FilterOperator.EQUAL, userId)).addSort(Book.TITLE, SortDirection.ASCENDING);
    PreparedQuery preparedQuery = datastore.prepare(query);
    QueryResultIterator<Entity> results = preparedQuery.asQueryResultIterator(fetchOptions);
    // Retrieve and convert Entities
    List<Book> resultBooks = entitiesToBooks(results);
    // Where to start next time
    Cursor cursor = results.getCursor();
    if (cursor != null && resultBooks.size() == 10) {
        // Are we paging? Save Cursor
        // Cursors are WebSafe
        String cursorString = cursor.toWebSafeString();
        return new Result<>(resultBooks, cursorString);
    } else {
        return new Result<>(resultBooks);
    }
}