46. Design Patterns
Subgraphs with no edge connected to the SubgraphInput component do not declare any input ports, therefore cannot receive input data so will likely be used as Readers.
Figure 305. Subgraph - Reader
Subgraphs with no edge connected to the SubgraphOutput component provide no output ports, therefore cannot produce any data so will likely be used as Writers.
Figure 306. Subgraph - Writer
Subgraph having connected both components (SubgraphInput and SubgraphOutput) is essentially a Transformer.
Figure 307. Subgraph - Transformer
Subgraphs with no edge connected to the SubgraphInput or SubgraphOutput components can be used as utility Executors. As they cannot be connected to other components in a parent graph, the execution of subgraphs without ports is controlled via Phases.
Figure 308. Subgraph - Executor