Check Interval, Task and Use Cases
The user may specify the minimum time interval between two checks. Use the Check every field to specify the interval in seconds.
Each listener defines a task which will be processed as a reaction to the file event. All task types and theirs attributes are described in the Scheduling and Graph Event Listeners sections.
Graph Execution when a file with input data is accessible.
Graph Execution when a file with input data is updated.
Graph Execution when a file with generated data is removed and must be recreated.
How to use source of event during task processing
A file(s) which caused the event (considered as a source of the event) may be used during task processing.
CloverDX graph/jobflow components with the File URL
attribute (e.g. reader or writer components) may directly use an event source by parameter placeholder:
${EVENT_FILE_URLS}.
For another parameters, see Executed by Task Graph Execution by File Event Listener.
Note that previous versions used lower-case placeholders. Since version 3.3, placeholders are upper-case, however lower-case still work for backward compatibility.
For graph execution task this works only if the graph is not pooled.
Thus keep in pool interval must be set to 0 (default value).
Delayed triggering for incomplete files
It is possible to delay task execution for incomplete files. This is useful in cases when the condition to execute the listener's task has been met, but there is still some work that needs to be done on the file, e.g. the whole file needs to be uploaded.
Ignore empty files
If the process creating the file creates an empty file, then switch to different task for several minutes or even hours and finally writes the content, tick Ignore empty files checkbox. The task will be triggered only if a non-empty file appears.
Trigger task when file has not changed for n checks
If the file size slowly rises until the file is complete, tick the checkbox Trigger task when file has not changed. Then specify the number of additional file size checks that are to be performed on the file. The listener's task will not be triggered until the checks are performed and the file's size stays the same between these checks.
Combination
If you use Ignore empty files and Trigger task when file has not changed for n checks together, the first one filters out empty files and the latter one the files that are being changed. The task will be triggered only on files that are not empty and that have not changed for the specified number of checks.