Groovy: constructor issue

Question

If I have a class like this:

class Person { 
def name
def greeting = "hello $name"
}

and I call bob = new Person(name: "bob")

when I inspect Bob at this point i see that the greeting does not have 'bob' in it. What am I doing wrong?

Answer 1

You can use the @Lazy annotation to get round this issue

class Person { 
  def name
  @Lazy def greeting = "hello $name"
}

bob = new Person(name: "bob")
println bob.greeting

Will print hello bob as you require. The annotation alters the getter for greeting so that it is only generated the first time it is called (and then the result is cached). This has the side effect of making greeting static once it has been called once, but you don't say whether it is required to change (due to name changing) over time... ie;

bob = new Person(name: "bob")
println bob.greeting
bob.name = 'dave'
println bob.greeting

Will print:

hello bob
hello bob