org.organicdesign.fp.function

Class LazyRef<T>

java.lang.Object

org.organicdesign.fp.function.LazyRef<T>

All Implemented Interfaces:

Callable<T>, Supplier<T>, Fn0<T>

public class LazyRef<T>
extends Object
implements Fn0<T>

Lazily initialize a value (and free the initialization resources) on the first call to get(). Subsequent calls to get() cheaply return the previously initialized value. This class is thread-safe if the producer function and the value it produces are free from side effects.

Method Summary

Modifier and Type	Method and Description
T	applyEx() The first call to this method calls the initialization function, caches the result, and hands the initialization function reference to the garbage collector so that initialization resources can be freed.
static <T> LazyRef<T>	of(Fn0<T> producer) Construct a LazyRef from the given initialization function.
String	toString() Useful for debugging, but not referentially transparent (sometimes returns LazyRef(*not-computed-yet*), sometimes shows the value that was computed).

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.organicdesign.fp.function.Fn0

apply, call, get

Method Detail

of

public static <T> LazyRef<T> of(Fn0<T> producer)

Construct a LazyRef from the given initialization function.

Parameters:

producer - a zero-argument function that produces the desired value when called.

Returns:

a LazyRef with the given producer.

applyEx

public T applyEx()

The first call to this method calls the initialization function, caches the result, and hands the initialization function reference to the garbage collector so that initialization resources can be freed. Subsequent calls return the precomputed value.

Specified by:

applyEx in interface Fn0<T>

Returns:

the same value every time it is called.

toString

public String toString()

Useful for debugging, but not referentially transparent (sometimes returns LazyRef(*not-computed-yet*), sometimes shows the value that was computed).

Overrides:

toString in class Object

Returns:

a string describing this LazyRef and showing whether or not its value has been computed yet.