Package de.team33.patterns.lazy.narvi

Class ReLazy<T>

java.lang.Object
de.team33.patterns.lazy.narvi.ReLazy<T>
All Implemented Interfaces:
Supplier<T>
public final class ReLazy<T> extends Object implements Supplier<T>
Implements a Supplier that provides a virtually fixed value(1). That value is only actually determined when it is accessed for the first time(2).

This implementation ensures that the originally defined initialization code is called at most once(1), even if there is concurrent access from multiple threads, unless the initialization attempt causes an (unchecked) exception.

Once the value is established, unnecessary effort to synchronize competing(3) read accesses is avoided.

(1) until reset().
(2) after initialization or after latest reset().
(3) Pure read accesses are of course not really competing.

See Also:

  • Method Details

    • init

      public static <T> ReLazy<T> init(Supplier<? extends T> initial)
      Returns a new instance giving a Supplier that defines the intended initialization of the represented value.
      Type Parameters:
      T - The result type of the initialisation code.
      See Also:

    • initEx

      public static <T> ReLazy<T> initEx(XSupplier<? extends T,?> initial)
      Returns a new instance giving an XSupplier that defines the intended initialization of the represented value. The initialization code may throw a checked exception. If so, it is caught, wrapped in an InitException, and rethrown.
      Type Parameters:
      T - The result type of the initialisation code.
      See Also:

    • get

      public final T get()
      Executes the originally defined initialization code once on the first call and returns its result on that and every subsequent call without executing the initialization code again. This method is thread safe.
      Specified by:
      get in interface Supplier<T>

    • reset

      public final ReLazy<T> reset()
      Resets this to the initial state and returns this.