Groovy: How to access a common object without injecting it into each class

[david-guild]

I am doing a lot of work with Script Runner and I have decided to build out a semi-framework.

One of my objects is a Logger Object that helps to enforce logging consistency across all the other objects.

public class LogThis
{
    // Properties
    def log
    def errorLevels = [
        debug: false,
        info : true,
        error: true
    ]
}

In this case, using this class, all info and error messages are displayed, but debug is not.  To turn on debug:

logger.enableDebug()

Is there a way, or is it bad practice in Groovy to make that class a global class that is accessible from inside of objects?

Currently I inject the log class into each object I instantiate:

(new Assignees(log))
    .setIssue(issue)
    .setNewAssignee(newAssignee)
    .commitChange()

This is a sample of calling a class that will change the assignee on an issue.  I am injecting the log object into the Assignees object.

I find that very, very repetitive, and not expandable.  If I need to start injecting another object, and another object, my class signature start to get unweildy at some point.

My inclination is to create some form of Dependency Injection Container (or IoC Container, etc, etc), but I have no idea if Groovy can handle that, or if it's even a Best Practice in Groovy.

This is kind of an "advanced" topic, but hopefully somebody wants to geek out on this subject :-)

Thanks in advance.

[Aron Gombas [Midori] · Accepted solution]

You could use the singleton design pattern: https://en.wikipedia.org/wiki/Singleton_pattern

Instead of injecting the logger into each class, the class could obtain it by calling the "getInstace()" method or just doing it the Groovy way: "Logger.instance".

[david-guild]

Thanks,

I just did not think of using a singleton in groovy at all.  Not sure why, maybe because singleton is such an anti pattern in my home language of PHP, that it just fell off the radar. 

Now I get to refactor a dozen or so scripts ...