Groovy: Add references to methods in a property to a parent object

Question

Say I have a class like this:

class Foo {
  def doFoo() {
    println "foo"
  }
}

And another like this:

class Bar {
  def doBar() {
    println "bar"
  }
}

And one more that looks like this:

class Baz {
  Foo foo = new Foo()
  Bar bar = new Bar()
}

With that example, what would it take to be able to use it like this:

Baz baz = new Baz()
baz.doFoo()
baz.doBar()

where the doFoo and doBar method calls simply delegate to the defined versions in their respective objects? Is there a way to do this with some kind of metaprogramming, or am I stuck defining each method individually as a wrapper?

Found another post that goes into more detail about AST transformations and traits: http://stackoverflow.com/a/23124968/493807 — Andy, Dec 01 '16 at 14:13

score 3 · Accepted Answer · answered Dec 01 '16 at 13:39

3

@Delegate is what you need:

class Foo {
  def doFoo() {
    println "foo"
  }
}

class Bar {
  def doBar() {
    println "bar"
  }
}

class Baz {
  @Delegate
  Foo foo = new Foo()
  @Delegate
  Bar bar = new Bar()
}

Baz baz = new Baz()
baz.doFoo()
baz.doBar()

answered Dec 01 '16 at 13:39

Opal

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Just found this myself. Still learning Groovy and loving it more every day! – Andy Dec 01 '16 at 13:46
@Andy, yes, it's really nice language. – Opal Dec 01 '16 at 13:51

Groovy: Add references to methods in a property to a parent object

1 Answers1