Example usage for com.mongodb CursorType Tailable

Introduction

In this page you can find the example usage for com.mongodb CursorType Tailable.

Prototype

CursorType Tailable

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Document

Tailable means the cursor is not closed when the last data is retrieved.

Usage

From source file:com.eightkdata.mongowp.client.wrapper.MongoConnectionWrapper.java

License:Open Source License

private CursorType toCursorType(QueryOptions queryOptions) {
    if (!queryOptions.isTailable()) {
        return CursorType.NonTailable;
    }/*from w  w  w  . j av a  2s  . co m*/
    if (queryOptions.isAwaitData()) {
        return CursorType.TailableAwait;
    }
    return CursorType.Tailable;
}

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From source file:com.streamsets.pipeline.stage.origin.mongodb.oplog.MongoDBOplogSource.java

License:Apache License

private void prepareCursor(int timestampSeconds, int ordinal, List<OplogOpType> filterOplogTypes,
        int batchSize) {
    LOG.debug("Getting new cursor with offset - TimeStampInSeconds:'{}', Ordinal : '{}' and Batch Size : '{}'",
            timestampSeconds, ordinal, batchSize);
    FindIterable<Document> mongoCursorIterable = mongoCollection.find()
            //As the collection is a capped collection we use Tailable cursor which will return results in natural order in this case
            //based on ts timestamp field.
            //Tailable Await does not return and blocks, so we are using tailable.
            .cursorType(CursorType.Tailable).batchSize(batchSize);

    List<Bson> andFilters = new ArrayList<>();
    //Only filter if we already have saved/initial offset specified or else both time_t and ordinal will not be -1.
    if (timestampSeconds > 0 && ordinal >= 0) {
        andFilters.add(Filters.gt(TIMESTAMP_FIELD, new BsonTimestamp(timestampSeconds, ordinal)));
    }/*from  ww w  .j  a  v  a  2s  .co m*/

    if (!filterOplogTypes.isEmpty()) {
        List<Bson> oplogOptypeFilters = new ArrayList<>();
        Set<OplogOpType> oplogOpTypesSet = new HashSet<>();
        for (OplogOpType filterOplogopType : filterOplogTypes) {
            if (oplogOpTypesSet.add(filterOplogopType)) {
                oplogOptypeFilters.add(Filters.eq(OP_TYPE_FIELD, filterOplogopType.getOp()));
            }
        }
        //Add an or filter for filtered Or Types
        andFilters.add(Filters.or(oplogOptypeFilters));
    }
    //Finally and timestamp with oplog filters
    if (!andFilters.isEmpty()) {
        mongoCursorIterable = mongoCursorIterable.filter(Filters.and(andFilters));
    }
    cursor = mongoCursorIterable.iterator();
}

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