How do you control which features arrive first for a transformer?

• A. FeatureTypeFilter (first feature type arrives first)
• B. Reader order (first reader is read first and so on)
• C. Transformer order (transformers alphabetically processed by name)
• D. Writer order (first writer is written first)

Answer: (B)

The concept being tested is how to control the sequence in which features arrive at a transformer. In FME, when a transformer has multiple input streams from different readers, you can set the Reader order to determine which stream’s features are delivered first. By configuring the Reader order, you specify that features from the first reader are pushed into the transformer before features from the second reader, and so on. This is essential when a downstream operation depends on receiving data from one source ahead of another or when you want predictable processing across runs. The other options don’t control arrival sequence: filtering by feature type is about selecting data, not ordering; there isn’t a notion of alphabetical transformer processing; and writer order affects output sequencing, not how input features arrive at a transformer. If you need explicit ordering within a single stream, you’d typically use a Sorter to arrange features by attributes after they’ve entered the flow.