setup the parallelDos of this input channel
sourceNode + environments for the parallelDo nodes
types of the keys which are emitted by this InputChannel, by tag
emit a new key/value using the parallelDos functions
setup the parallelDos of this input channel
data source for this input channel
main source node providing data for this input channel
set of tags, which are node ids consuming the values produced by this input channel
types of the values which are emitted by this InputChannel, by tag
An input channel groups mapping operations from a single DataSource, attached to a source node (a Load node, or a GroupByKey node from a previous Mscr for example).
There are however more data inputs for an InputChannel since the environments of ParallelDos are inputs as well
An InputChannel emits (key, values) of different types classified by an Integer tag, either:
The main functionality of an InputChannel is to map an input key/value to another key/value to be grouped or reduced using the functions of ParallelDos.
There are 2 main types of InputChannels:
They both share some implementation in the MscrInputChannel trait.
An input channel can have no mappers at all. In that case the values from the source node are directly emitted with no transformation.
Two InputChannels are equal if they have the same source id.