Examples of com.mongodb.DBCursor

com.mongodb.DBCursor
An iterator over database results. Doing a find() query on a collection returns a DBCursor thus
```
 DBCursor cursor = collection.find( query ); if( cursor.hasNext() ) DBObject obj = cursor.next(); 
```
Warning: Calling toArray or length on a DBCursor will irrevocably turn it into an array. This means that, if the cursor was iterating over ten million results (which it was lazily fetching from the database), suddenly there will be a ten-million element array in memory. Before converting to an array, make sure that there are a reasonable number of results using skip() and limit().
For example, to get an array of the 1000-1100th elements of a cursor, use
```
 List obj = collection.find( query ).skip( 1000 ).limit( 100 ).toArray(); 
```
@dochub cursors


                    QueryBuilder query = QueryBuilder.start(Document.ID)
                            .in(sameLevelNodes.keySet());


                    // Fetch lastRev and modCount for each such nodes
                    DBCursor cursor = nodes.find(query.get(), keys);
                    LOG.debug(
                            "Checking for changed nodes at level {} with {} paths",
                            tn.level(), sameLevelNodes.size());
                    result.queryCount++;
                    for (DBObject obj : cursor) {

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            queryBuilder.greaterThanEquals(startValue);
        }
        DBObject query = queryBuilder.get();
        long start = start();
        try {
            DBCursor cursor = dbCollection.find(query).sort(BY_ID_ASC);
            List<T> list = new ArrayList<T>();
            for (int i = 0; i < limit && cursor.hasNext(); i++) {
                DBObject o = cursor.next();
                T doc = convertFromDBObject(collection, o);
                if (collection == Collection.NODES && doc != null) {
                    doc.seal();
                    String id = doc.getId();
                    Lock lock = getAndLock(id);

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            // Fetch only the lastRev map and id
            final BasicDBObject keys = new BasicDBObject(Document.ID, 1);
            keys.put(Document.MOD_COUNT, 1);


            // Fetch lastRev for each such node
            DBCursor cursor = nodes.find(query.get(), keys);
            result.queryCount++;
            for (DBObject obj : cursor) {
                result.cacheEntriesProcessedCount++;
                String id = (String) obj.get(Document.ID);
                Number modCount = (Number) obj.get(Document.MOD_COUNT);

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        queryBuilder.and("_id").greaterThan(parent + "/");
        queryBuilder.and("_id").lessThanEquals(parent + "0");
        DBObject query = queryBuilder.get();
        BasicDBObject keys = new BasicDBObject();
        keys.put("_id", 1);
        DBCursor cursor = nodes.find(query, keys);
        int count = 0;
        log("Query plan: " + cursor.explain());
        long time = System.currentTimeMillis();
        while (cursor.hasNext()) {
            DBObject obj = cursor.next();
            // dummy read operation (to ensure we did get the data)
            obj.get("_id");
            count++;
            // log(" read " + obj);
        }

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  private MongoDBResultTupleIterable getResultsCursor() {
    EntityKeyMetadata keyMetaData = getKeyMetaData( entityType );
    DBCollection collection = provider.getDatabase().getCollection( keyMetaData.getTable() );


    DBCursor cursor = isProjection() ? collection.find( query, projections ) : collection.find( query );


    return new MongoDBResultTupleIterable( cursor, keyMetaData );
  }

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            queryBuilder.greaterThanEquals(startValue);
        }
        DBObject query = queryBuilder.get();
        long start = start();
        try {
            DBCursor cursor = dbCollection.find(query);
            List<T> list = new ArrayList<T>();
            for (int i = 0; i < limit && cursor.hasNext(); i++) {
                DBObject o = cursor.next();
                T doc = convertFromDBObject(collection, o);
                if (collection == Collection.NODES && doc != null) {
                    doc.seal();
                    nodesCache.put(doc.getId(), (NodeDocument) doc);
                }

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        queryBuilder.and("_id").greaterThan(parent + "/");
        queryBuilder.and("_id").lessThanEquals(parent + "0");
        DBObject query = queryBuilder.get();
        BasicDBObject keys = new BasicDBObject();
        keys.put("_id", 1);
        DBCursor cursor = nodes.find(query, keys);
        int count = 0;
        log("Query plan: " + cursor.explain());
        long time = System.currentTimeMillis();
        while (cursor.hasNext()) {
            DBObject obj = cursor.next();
            // dummy read operation (to ensure we did get the data)
            obj.get("_id");
            count++;
            // log(" read " + obj);
        }

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    query.put(MongoDbDeltaStoreUtil.FIELD_WAVE_ID, waveId.serialise());


    DBObject projection = new BasicDBObject();
    projection.put(MongoDbDeltaStoreUtil.FIELD_WAVELET_ID, 1);


    DBCursor cursor = null;


    try {
      cursor = getDeltaDbCollection().find(query, projection);
    } catch (MongoException e) {
      throw new PersistenceException(e);
    }




    if (cursor == null || !cursor.hasNext()) {
      return ImmutableSet.of();
    } else {
      ImmutableSet.Builder<WaveletId> builder = ImmutableSet.builder();
      for (DBObject waveletIdDBObject : cursor) {
        builder.add(WaveletId.deserialise((String) waveletIdDBObject

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    }


    @Override
    public Iterator<StateReader> instancesOf(final ObjectSpecId objectSpecId) {
        final DBCollection instances = db.getCollection(objectSpecId.asString());
        final DBCursor cursor = instances.find();
        LOG.info("searching for instances of: " + objectSpecId);
        return new Iterator<StateReader>() {
            @Override
            public boolean hasNext() {
                return cursor.hasNext();
            }


            @Override
            public StateReader next() {
                return new MongoStateReader(cursor.next());
            }


            @Override
            public void remove() {
                throw new NoSqlStoreException("Can't remove elements");

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                } else if (association.isOneToOneAssociation()) {
                    query.put(association.getIdentifier().getMemberName(), field.getOid());
                }
            }
        }
        final DBCursor cursor = instances.find(query);
        LOG.info("searching for instances of: " + objectSpecId);
        return new Iterator<StateReader>() {
            @Override
            public boolean hasNext() {
                return cursor.hasNext();
            }


            @Override
            public StateReader next() {
                return new MongoStateReader(cursor.next());
            }


            @Override
            public void remove() {
                throw new NoSqlStoreException("Can't remove elements");

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