groovy.lang
Annotation Type Lazy

@Retention(value=SOURCE)
@Target(value=FIELD)
public @interface Lazy

Field annotation to make a field lazy initializable. If the field is declared volatile then initialization will be synchronized.

 @Lazy volatile T x
 

becomes

 private volatile T $x

 T getX () {
   if ($x != null)
     return $x
   else {
     synchronized(this) {
        $x = new T ()
        return $x
     }
   }
 }
 

By default a field will be initialized by calling its default constructor. If the field has an initial value expression then this expression will be used instead of default constructor. In particular, it is possible to use closure { ... } () syntax as follows:

 @Lazy T x = { [1,2,3] } ()
 

becomes

 private T $x

 T getX () {
   if ($x != null)
     return $x
   else {
     $x = { [1, 2, 3] } ()
     return $x
   }
 }
 

@Lazy(soft=true) will use a soft reference instead of the field and use the above rules each time re-initialization is required.

Author:

Alex Tkachman

Optional Element Summary

boolean

soft

soft

public abstract boolean soft

Returns:

if field should be soft referenced instead of hard referenced

Default:

false