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:

• Lazy
• XReLazy

Method Summary

Modifier and Type	Method	Description
final T	get()
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.
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.
final ReLazy<T>	reset()	Resets this to its initial state and returns this.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

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(XSupplier)

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:

• init(Supplier)

get

public final T get()

This implementation executes the originally defined initialization code once on the first call⁽¹⁾ and returns its result on that and every subsequent call without executing the initialization code again⁽²⁾.

This implementation is thread safe.

⁽¹⁾ after creation or after latest reset().
⁽²⁾ until next reset().

Specified by:

get in interface Supplier<T>

reset

public final ReLazy<T> reset()

Resets this to its initial state and returns this.