Examples with AggregateIterable com.mongodb.client.AggregateIterable used on opensource projects

Example 1 with AggregateIterable

use of com.mongodb.client.AggregateIterable in project spring-data-mongodb by spring-projects.

the class MongoTemplate method aggregateStream.

@SuppressWarnings("ConstantConditions")
protected <O> CloseableIterator<O> aggregateStream(Aggregation aggregation, String collectionName, Class<O> outputType, @Nullable AggregationOperationContext context) {
    Assert.hasText(collectionName, "Collection name must not be null or empty!");
    Assert.notNull(aggregation, "Aggregation pipeline must not be null!");
    Assert.notNull(outputType, "Output type must not be null!");
    Assert.isTrue(!aggregation.getOptions().isExplain(), "Can't use explain option with streaming!");
    AggregationOperationContext rootContext = context == null ? Aggregation.DEFAULT_CONTEXT : context;
    AggregationOptions options = aggregation.getOptions();
    List<Document> pipeline = aggregation.toPipeline(rootContext);
    if (LOGGER.isDebugEnabled()) {
        LOGGER.debug("Streaming aggregation: {} in collection {}", serializeToJsonSafely(pipeline), collectionName);
    }
    ReadDocumentCallback<O> readCallback = new ReadDocumentCallback<>(mongoConverter, outputType, collectionName);
    return execute(collectionName, (CollectionCallback<CloseableIterator<O>>) collection -> {
        AggregateIterable<Document> cursor = collection.aggregate(pipeline, Document.class).allowDiskUse(options.isAllowDiskUse()).useCursor(true);
        if (options.getCursorBatchSize() != null) {
            cursor = cursor.batchSize(options.getCursorBatchSize());
        }
        if (options.getCollation().isPresent()) {
            cursor = cursor.collation(options.getCollation().map(Collation::toMongoCollation).get());
        }
        return new CloseableIterableCursorAdapter<>(cursor.iterator(), exceptionTranslator, readCallback);
    });
}