Re: How to access global variables from a class?

[Per Nyfelt]

Another way which maybe is slightly more what you are after is to 
augment the class e.g:

@Grab('org.slf4j:slf4j-simple:2.0.16')
import org.slf4j.LoggerFactory
import org.slf4j.Logger
import groovy.transform.Field
logger = LoggerFactory.getLogger("l")

class A {
  A() {
    logger.info("L")
  }
}
A.metaClass.logger = logger
A a = new A()


Or you can pass the binding to the class. From there you can get any 
"globally" defined variables i.e:

@Grab('org.slf4j:slf4j-simple:2.0.16')
import org.slf4j.LoggerFactory
import org.slf4j.Logger
import groovy.transform.Field

@Field Logger logger = LoggerFactory.getLogger("l")

class A {
  Logger logger
  public A(Binding binding) {
    logger = binding.logger
    logger.info("L")
  }
}
A a = new A(binding)


Another idea would be to use a closure instead of a class which may or 
may not be feasible in your case:

@Grab('org.slf4j:slf4j-simple:2.0.16')
import org.slf4j.LoggerFactory
import org.slf4j.Logger

logger = LoggerFactory.getLogger("l")

def c = {
    logger.info("L")
}
c.call()

On 9/23/24 22:17, Per Nyfelt wrote:

You have a scope problem and need to move the logger declaration into 
your A class. Also if slf4j is not available in your classpath, @Grab 
is your friend.

The following works when running the script in the GroovyScriptEngine:

@Grab('org.slf4j:slf4j-simple:2.0.16')
import org.slf4j.LoggerFactory
import org.slf4j.Logger

class A {
  Logger logger = LoggerFactory.getLogger("l")
  public A() {
    logger.info("L")
  }
}
A a = new A()

Note: I don't know how OpenHAB is executing the Groovy code. If it is 
using the GroovyShell then use 
groovy.grape.Grape.grab('org.slf4j:slf4j-simple:2.0.16') instead.See 
https://docs.groovy-lang.org/latest/html/documentation/grape.html for 
details.

Hope this helps.

On 8/21/24 13:16, Дилян Палаузов via users wrote:
Hello,

OpenHAB 4.2.1 is written in Java and has a Groovy 4.0.11 plugin to programme 
logic.  It allows writing code outside of classes, which is executed 
immediately.  When I place a file openhab/jsr223/test.groovy:


   import org.slf4j.LoggerFactory
  
   logger = LoggerFactory.getLogger("l")
  
   class A {
     public A() {
       logger.info("L")
     }
   }
   A a = new A()


the system logs

2024-08-21 12:15:21.061 [ERROR] [ipt.internal.ScriptEngineManagerImpl] - Error 
during evaluation of script ‘/etc/openhab/automation/jsr223/test.groovy’: 
javax.script.ScriptException: groovy.lang.MissingPropertyException: No such 
property: logger for class: A

How can I make logger visible within the methods of class A, without passing it 
as parameter to the constructor?

Also asked 
athttps://community.openhab.org/t/groovy-how-to-access-global-variable-from-a-class/
 .

Kind regards
   Дилян