Comprehensive and Detailed Explanation:
The OIC FTP Adapter in theInvoke rolefacilitates interactions with an FTP server from an integration flow. Let’s break down each operation with exhaustive detail:
Option A: Write File
Supported:The FTP Adapter allows writing files to an FTP server. For example, you could use a Stage File action to prepare a CSV file and then invoke the FTP Adapter to write it to a remote directory like /inbound. This is a core capability for outbound file transfers.
Option B: Read File
Supported:Reading an entire file from an FTP server is possible in Invoke mode. You specify a file path (e.g., /outbound/data.csv), and the adapter retrieves itscontents, useful for processing complete files in one go, like a daily report.
Option C: Read File in Segments
Not Supported (Answer):This operation, which processes large files incrementally (e.g., 100 records at a time), is exclusive to theTrigger roleor Stage File actions, not the Invoke role of the FTP Adapter. In Invoke mode, the adapter doesn’t support segmented reading because it’s designed for direct, one-shot operations rather than iterative processing. For segmented reads, you’d use a File Adapter in Trigger mode or Stage File with a Connectivity Agent.
Option D: Delete File
Supported:Deleting a file on the FTP server (e.g., /archive/oldfile.txt) is a standard Invoke operation, often used for cleanup after processing.
Option E: Download File
Supported:Downloading retrieves a file to OIC for further processing, similar to Read File but typically implies storing it locally in the integration flow (e.g., staging it).
Why C is the Answer:The Invoke role focuses on discrete actions (write, read, delete, download), not iterative tasks like segmented reading, which requires a polling mechanism better suited to Trigger roles or Stage File actions.
Edge Case:If you need segmented reading from an FTP server, you’d download the file first using Invoke, then use a Stage File action to process it in segments— a workaround, not a direct capability.
Use Case Example:An integration writing a sales report to FTP (A), downloading a log file (E), and deleting an old backup (D) works fine, but attempting to read a 10GB file in segments (C) fails in Invoke mode.
[References:Oracle Integration Cloud documentation, “FTP Adapter Capabilities” and “Invoke vs. Trigger Roles” sections., , ]
