Groovy's ExpandoMetaClass features allows us to override the getProperty() method for a class. This method is invoked if we want to access a property for an object. We can look up existing properties and return their result, but we can also write behaviour for the situation when the property doesn't exist.
class User {
String username
}
User.metaClass.getProperty = { String propName ->
def meta = User.metaClass.getMetaProperty(propName)
if (meta) {
meta.getProperty(delegate)
} else {
'Dynamic property for User'
}
}
def mrhaki = new User(username: 'mrhaki')
def hubert = new User(username: 'hubert')
assert 'mrhaki' == mrhaki.username
assert 'Dynamic property for User' == mrhaki.fullname
