groovy.lang
[Java] Annotation Type Newify

java.lang.Object
  groovy.lang.Newify

@Retention(RetentionPolicy.SOURCE)
@Target({ElementType.CONSTRUCTOR, ElementType.METHOD, ElementType.TYPE, ElementType.FIELD, ElementType.LOCAL_VARIABLE})
@GroovyASTTransformationClass("org.codehaus.groovy.transform.NewifyASTTransformation")
public @interface Newify

Annotation that supports writing constructor call expressions without the 'new' keyword. Instead they can be written "Ruby-style" as a method call to a 'new' method or "Python-style" by just omitting the keyword missing.

It allows you to write code snippets like this ("Python-style"):

 @Newify([Tree,Leaf]) class MyTreeProcessor {
     def myTree = Tree(Tree(Leaf("A"), Leaf("B")), Leaf("C"))
     def process() { ... }
 }
 

 @Newify class MyTreeProcessor {
     def myTree = Tree.new(Tree.new(Leaf.new("A"), Leaf.new("B")), Leaf.new("C"))
     def process() { ... }
 }
 

 class MyTreeProcessor {
     def myTree = new Tree(new Tree(new Leaf("A"), new Leaf("B")), new Leaf("C"))
     def process() { ... }
 }
 

The "Ruby-style" new conversions occur automatically unless the 'auto=false' flag is given when using the annotation. You might do this if you create a new method using meta programming.

The "Python-style" conversions require you to specify each class on which you want them to apply. The transformation then works by matching the basename of the provided classes to any similarly named instance method calls not specifically bound to an object, i.e. associated with the 'this' object. In other words Leaf("A") would be transformed to new Leaf("A") but x.Leaf("A") would not be touched.

An example showing how to use the annotation at different levels:

 @Newify(auto=false, value=Foo)
 class Main {
     @Newify // turn auto on for field
     def field1 = java.math.BigInteger.new(42)
     def field2, field3, field4

     @Newify(Bar)
     def process() {
         field2 = Bar("my bar")
     }

     @Newify(Baz)
     Main() {
         field3 = Foo("my foo")
         field4 = Baz("my baz")
     }
 }
 

Authors:

Paul King

auto

public boolean auto

@default true

Returns:

if automatic conversion of "Ruby-style" new method calls should occur

value

public Class[] value

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