[GROOVY-3723] EMC weirdness: adding properties and setProperty/getProperty in common

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.6.3, 1.6.4
• Fix Version/s: 1.6.5, 1.7-beta-2
• Environment: 64bit Linux, Sun JVM 1.6.0-14
• Assignee: Roshan Dawrani
• Reporter: Stefan Armbruster
• Created: 03/Sep/09 01:44
• Updated: 15/Oct/09 17:15
• Resolved: 03/Sep/09 03:36

Description

I observed some weird behaviour if a property is added to a class by EMC and getProperty/setProperty are also handled by EMC:

class Dummy {
   def name
}

Dummy.metaClass.id = 1

Dummy.metaClass.getProperty = { name ->
   def metaProperty = delegate.metaClass.getMetaProperty(name)
   // do some other stuff here...
   println "getting $name"
   return metaProperty?.getProperty(delegate)
}

Dummy.metaClass.setProperty = { name, value ->
   def metaProperty = delegate.metaClass.getMetaProperty(name)
   // do some other stuff here....
   println "setting $name"
   metaProperty?.setProperty(delegate,value)
}

// setting & getting "normal" properties works
def d= new Dummy(name:"I am Dummy")
assert "I am Dummy", d.name

// setting & getting "injected" properties fail
d.id = 123  // fails with groovy.lang.GroovyRuntimeException: Cannot set read-only property: id
println d.id // fails with groovy.lang.GroovyRuntimeException: Cannot read write-only property: id

In case of a "normal" property ("name"), metaProperty is a groovy.lang.MetaBeanProperty. For a injected property ("id") it's a ThreadManagedMetaBeanProperty. The trouble is IMHO that the constructors of ThreadManagedMetaBeanProperty do not pass its customized setter/getter using setSetter() and setGetter() to its parent object. Is there any reason why ThreadManagedMetaBeanProperty stores these values locally? To solve this, I use the following ugly workaround:

Dummy.metaClass.getProperty = { name ->
   def metaProperty = delegate.metaClass.getMetaProperty(name)
   // do some other stuff here...
   println "getting $name"
   if (metaProperty instanceof ThreadManagedMetaBeanProperty) {
       return metaProperty.getGetter().invoke(delegate,
MetaClassHelper.EMPTY_ARRAY);
   } else {
       return metaProperty.getProperty(delegate)
   }
}

Dummy.metaClass.setProperty = { name, value ->
   def metaProperty = delegate.metaClass.getMetaProperty(name)
   // do some other stuff here...
   println "setting $name $value"
   if (metaProperty==null) return false

   if (metaProperty instanceof ThreadManagedMetaBeanProperty) {
       return metaProperty.getSetter().invoke(delegate, value)
   } else {
       return metaProperty.setProperty(delegate,value)
   }
}

This has been discussed in the mailing list: http://www.nabble.com/EMC%3A-adding-properties-and-setProperty-getProperty-in-common-td25262367.html
Roshan already fixed this locally.