How to Set Max Iterations in a Custom Looper FMX with a Variable

That is odd. I've never used it the way you do, but it should work right?

As a workaround: if the (looping part of your) transformer does not contain any blocking transformers (e.g. FeatureHolder, FeatureMerger etc.), you can set the "Enabled blocked looping" property to "No" and then break out of the loop yourself.

 

Just add a Published Parameter the way you normally do (either by adding it in the nav panel or by exposing/adding an attribute on the Input port) that will hold the max iterations, e.g. MAX_ITER. Then add an AttributeCreator/Manager right after the Input port that will set an iteration count attribute (e.g. _iter) and give it a value of 0. Right before the features enter the Loop port, add a Tester that will check if the _iter attribute is equal to $(MAX_ITER). Connect Passed to the Output port/branch and Failed to the Loop port. Finally, add an AttributeCreator/Manager within the loop that adds +1 (or whatever your step size is) to the _iter attribute.

You should now be able to set the max iterations through another Published Parameter in your main workspace (or even an attribute!).

That is odd. I've never used it the way you do, but it should work right?

As a workaround: if the (looping part of your) transformer does not contain any blocking transformers (e.g. FeatureHolder, FeatureMerger etc.), you can set the "Enabled blocked looping" property to "No" and then break out of the loop yourself.

 

Just add a Published Parameter the way you normally do (either by adding it in the nav panel or by exposing/adding an attribute on the Input port) that will hold the max iterations, e.g. MAX_ITER. Then add an AttributeCreator/Manager right after the Input port that will set an iteration count attribute (e.g. _iter) and give it a value of 0. Right before the features enter the Loop port, add a Tester that will check if the _iter attribute is equal to $(MAX_ITER). Connect Passed to the Output port/branch and Failed to the Loop port. Finally, add an AttributeCreator/Manager within the loop that adds +1 (or whatever your step size is) to the _iter attribute.

You should now be able to set the max iterations through another Published Parameter in your main workspace (or even an attribute!).

Thanks @sander_s. I'll give this a go...

That's interesting. I'll file a request with our developers as I don't see why that couldn't be set as an attribute.

I see another option is to "Open Text Editor". Could you pick it from the attribute there? ie use @Value(<AttributeName>)

Filed as PR#68350 - but I'm not confident it's something we could do (or that any workaround I suggest would work)

Yes, some type blocking transformer do allow it others don't..

Always thought that was strange.

But you can overcome it with a scripted parameter by putting the blocking transformer in a normal custom transformer.

The scripted parameter parameters need to be parameters.

These are then accesible trhough the normal "wrapping"customtrnasformer.

Like this:

itnf-max-it-setup.png(404.2 kB)

where wrapper is

That is odd. I've never used it the way you do, but it should work right?

As a workaround: if the (looping part of your) transformer does not contain any blocking transformers (e.g. FeatureHolder, FeatureMerger etc.), you can set the "Enabled blocked looping" property to "No" and then break out of the loop yourself.

 

Just add a Published Parameter the way you normally do (either by adding it in the nav panel or by exposing/adding an attribute on the Input port) that will hold the max iterations, e.g. MAX_ITER. Then add an AttributeCreator/Manager right after the Input port that will set an iteration count attribute (e.g. _iter) and give it a value of 0. Right before the features enter the Loop port, add a Tester that will check if the _iter attribute is equal to $(MAX_ITER). Connect Passed to the Output port/branch and Failed to the Loop port. Finally, add an AttributeCreator/Manager within the loop that adds +1 (or whatever your step size is) to the _iter attribute.

You should now be able to set the max iterations through another Published Parameter in your main workspace (or even an attribute!).

Hi @sander_s. I took another stab at your approach and it seems to work. So I'm going to claim victory over this workbench and not fuss with it anymore! Thanks to @gio and @Mark2AtSafe for the input so far on this!