de.team33.patterns.lazy.narvi

Class XLazy<T,X extends Exception>

java.lang.Object

de.team33.patterns.lazy.narvi.XLazy<T,X>

public class XLazy<T,X extends Exception>
extends Object

Implements a kind of supplier that provides a virtually fixed value. That value is only actually determined when it is accessed for the first time.

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

Once the value is established, unnecessary effort to synchronize competing* read accesses is avoided.

*Pure read accesses are of course not really competing.

See Also:

Lazy

Method Summary

Modifier and Type	Method and Description
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.
static <T,X extends Exception> XLazy<T,X>	init(XSupplier<? extends T,? extends X> initial) Returns a new XLazy instance giving a Supplier that defines the intended initialization of the represented value.

Methods inherited from class java.lang.Object

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

Method Detail

init

public static <T,X extends Exception> XLazy<T,X> init(XSupplier<? extends T,? extends X> initial)

Returns a new XLazy instance giving a Supplier that defines the intended initialization of the represented value.

Type Parameters:

T - The result type of the initialisation code.

X - The exception type that may occur within initialisation.

get

public final T get()
            throws X extends Exception

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.

Throws:

X extends Exception