driver-legacy/src/main/com/mongodb/DBCursor.java
public DBCursor setDecoderFactory(final DBDecoderFactory factory) {
        this.decoderFactory = factory;

        //Not creating new CompoundDBObjectCodec because we don't care about encoder.
        this.decoder = new DBDecoderAdapter(factory.create(), collection, getCollection().getBufferPool());
        return this;
    }
public DBCursor setDecoderFactory(final DBDecoderFactory factory) {
        this.decoderFactory = factory;

        //Not creating new CompoundDBObjectCodec because we don't care about encoder.
        this.decoder = new DBDecoderAdapter(factory.create(), collection, getCollection().getBufferPool());
        return this;
    }
Sets the factory that will be used create a {@code DBDecoder} that will be used to decode BSON documents into DBObject instances.

@param factory the DBDecoderFactory
@return {@code this} so calls can be chained