org.mule.runtime.api.util

Class LazyValue<T>

java.lang.Object

org.mule.runtime.api.util.LazyValue<T>

Type Parameters:

T - the generic type of the provided value

public class LazyValue<T>
extends Object

Provides a value which may be lazily computed.

The value is only computed on the first invokation of get(). Subsequent calls to such method will always return the same value.

This class is thread-safe. When invoking get(), it is guaranteed that the value will be computed only once.

Since:

1.0

Constructor Summary

Constructors

Constructor and Description
LazyValue(Supplier<T> supplier) Creates a new instance which lazily obtains its value from the given supplier.
LazyValue(T value) Creates a new instance which is already initialised with the given value.

Method Summary

Modifier and Type	Method and Description
<R> R	flatMap(Function<T,R> function) Applies the given function through the output of get().
T	get() Returns the lazy value.
void	ifComputed(Consumer<T> consumer) If the value has already been computed, if passes it to the given consumer.
boolean	isComputed()

Methods inherited from class java.lang.Object

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

Constructor Detail

LazyValue

public LazyValue(Supplier<T> supplier)

Creates a new instance which lazily obtains its value from the given supplier. It is guaranteed that Supplier.get() will only be invoked once. Because this class is thread-safe, the supplier is not required to be.

Parameters:

supplier - A Supplier through which the value is obtained

LazyValue

public LazyValue(T value)

Creates a new instance which is already initialised with the given value.

Parameters:

value - the initialization value

Method Detail

get

public T get()

Returns the lazy value. If the value has not yet been computed, then it does so

Returns:

the lazy value

isComputed

public boolean isComputed()

Returns:

Whether the value has already been calculated.

ifComputed

public void ifComputed(Consumer<T> consumer)

If the value has already been computed, if passes it to the given consumer. This method does not perform any synchronization so keep in mind that dirty reads are possible if this method is being called from one thread while another thread is triggering the value's computation

Parameters:

consumer - a Consumer

flatMap

public <R> R flatMap(Function<T,R> function)

Applies the given function through the output of get(). If the value has not already been computed, this method will trigger computation. This method is thread-safe.

Type Parameters:

R - the generic type of the function's output

Parameters:

function - a transformation function

Returns:

a transformed value