[GROOVY-4730] Cannot create static property via metaClass

• Type: Sub-task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.7.6
• Component/s: groovy-runtime
• Environment: Linux, Fedora 13, Vaio F12
• Assignee: Unassigned
• Reporter: James Lang
• Created: 17/Mar/11 00:28
• Updated: 25/Nov/13 08:59

Description

As per this thread on Groovy User:
http://groovy.329449.n5.nabble.com/Cannot-create-static-property-via-metaClass-td3792536.html#a3832577

I am unable to do the following:
class Foo {}
Foo.metaClass.static.bar = 1
Foo.bar // error, no such property bar for class Foo

Suggested non-working workaround:
class Foo {}
Foo.metaClass.static.getBar =

{ 1 }

Foo.metaClass.static.setBar =

{ Integer x->bar=x }

println Foo.bar // 1
Foo.bar = 5
println Foo.bar // obviously, still 1 since static bar property is never created, just creating static getter/setter for a non-existent foo

Interestingly, running above code once, and then swapping getBar=

{1}

with getBar=

{bar}

, the code works and one can overwrite the initial value.

On a side note: when we are able to create an MCL static properties, what will the scope be? i.e. same as
class Foo {
static bar
}

I ask because I am unsure where groovy MOP and JVM garbage collection come into play. I stumbled across this problem as I was attempting to create a per request singleton (via MCL), as opposed to application/instance lifetime scoped with
class Foo {
private static final bar = new Thing()
}

Thanks for evolving Groovy, now & the future are very bright.