[DSL] Cannot import org.openhab.core.util namespace

[jsetton]

It is not possible to import the org.openhab.core.util namespace with the DSL rule engine.

import org.openhab.core.util.ColorUtil

rule "ColorItem Changes"
when
  Item ColorItem changed
then
  val rgb = ColorUtil.hsbToRgb(ColorItem.state as HSBType)
  logInfo("ColorItem", "RGB: {},{},{}", rgb.get(0), rgb.get(1), rgb.get(2))
end

Each time this rule is called, the following error is generated:

[ERROR] [internal.handler.ScriptActionHandler] - Script execution of rule with UID 'test-1' failed: The name 'ColorUtil' cannot be resolved to an item or type; line 7, column 12, length 9 in test

[openhab-bot]

This issue has been mentioned on openHAB Community. There might be relevant details there:

https://community.openhab.org/t/oh4-hsbtype-is-deprecated-warning/148080/12

[lolodomo]

Did you try?
val rgb = hsbToRgb(ColorItem.state as HSBType)

[jsetton]

Same error.

The name 'hsbToRgb' cannot be resolved to an item or type

[lolodomo]

Sorry for my stupid suggestion.
ColorUtil is the class mame and org.openhab.core.util the package.
This package is public.
I hope there is not somewhere a hardcoded list of accepted packages by DSL rules.

[lolodomo]

Maybe to be added here?
https://github.com/openhab/openhab-core/blob/main/bundles/org.openhab.core.model.script/src/org/openhab/core/model/script/scoping/ScriptImportSectionNamespaceScopeProvider.java

Those defined here do not need any explicit import.

[lolodomo]

I will do this change and then test if your rule example is working without the import.

[lolodomo]

Or even rather add ColorUtil as implicitly imported class here
https://github.com/openhab/openhab-core/blob/main/bundles/org.openhab.core.model.script/src/org/openhab/core/model/script/scoping/ScriptImplicitlyImportedTypes.java

[lolodomo]

Unfortunately, I do not succeed to make it work.

10:18:15.371 [ERROR] [.xtext.validation.CompositeEValidator] - Error executing EValidator
java.lang.NoClassDefFoundError: org/openhab/core/util/ColorUtil
        at org.openhab.core.model.script.scoping.ScriptImplicitlyImportedTypes.getStaticImportClasses(ScriptImplicitlyImportedTypes.java:119) ~[?:?]
        at org.eclipse.xtext.xbase.scoping.batch.ImplicitlyImportedFeatures.getStaticImportClasses(ImplicitlyImportedFeatures.java:67) ~[?:?]

...

Caused by: java.lang.ClassNotFoundException: org.openhab.core.util.ColorUtil cannot be found by org.openhab.core.model.script_4.1.0.202308110815

Even if the changed code is compiling, at runtime, org.openhab.core.model.script is not "seeing" org.openhab.core.util.
I do not understand why !

[jsetton]

Shouldn't the package org.openhab.core.util be added as Import-Package to the org.openhab.core.model.script bnd file?

[lolodomo]

Shouldn't the package org.openhab.core.util be added as Import-Package to the org.openhab.core.model.script bnd file?

Probably. I will try.

[lolodomo]

Ok, it solved my exception.

Unfortunately, my change has no impact, I still get: The name 'ColorUtil' cannot be resolved to an item or type

[lolodomo]

By the way, I searched in my existing rules the syntax to call static methods and apparently the syntax would be ColorUtil::hsbToRgb(val)
Example:

var int idx = Integer::parseInt(params.get(0))

But it does not solve the issue !

[lolodomo]

Do you have another working example with a call to a static method provided by openHAB ?

[jsetton]

Do you have another working example with a call to a static method provided by openHAB ?

Is this relevant at this stage of the issue? I would expect an error at the method level once the org.openhab.core.util.ColorUtil package can be imported. Nevertheless, I think you might be right in the fact it should be called as ColorUtil::hsbToRgb.

[lolodomo]

If I had a working example, I could try to understand what is the difference.
What annoys me a little is that we are even not sure what is the expected syntax!

[jsetton]

Apparently, it doesn't seem to matter how it is called.

https://eclipse.dev/Xtext/xtend/documentation/203_xtend_expressions.html#static-access

[lolodomo]

Maybe the only solution would be to add actions napping ColorUtil methods.

https://github.com/openhab/openhab1-addons/wiki/Actions

I think you can't with DSL rules import any Java package you like. That is certainly the root cause.
I thought my proposed change would allow importing a specific class but I was not able to make it work.

[jsetton]

I don't have enough knowledge to weigh in on your proposed solution. It seems a bit overkill though.

The org.openhab.core.library packages from the same module are imported.

[lolodomo]

It should be definitively possible to make ColorUtil class implicitly imported. It is what I am trying to achieve.
It is what we are already doing for example for Exec class (method executeCommandLine) or Log class (method logInfo, ...).
Once done, no need to use ColorUtil, just use the method name.
Normally, what I have done should be sufficient. There is probably something obvious that I miss !

[jsetton]

There are other classes in org.openhab.core.util that would be useful.

[lolodomo]

Ok, I am able to make it work but I need to define a class in org.openhab.core.model.script.actions mapping all static methods of ColorUtil.

But then, we can take care to also expose the methods to UI. Edit: makes probably no sense to expose these utils directly as actions for the user in UI. But of course, they will be usable inside a UI script.