org.apache.jackrabbit.oak.commons

Class LazyValue<T>

java.lang.Object

org.apache.jackrabbit.oak.commons.LazyValue<T>

All Implemented Interfaces:

Supplier<T>

public abstract class LazyValue<T>
extends Object
implements Supplier<T>

An instances of this class represents a lazy value of type T. LazyValue implements an evaluate by need semantics: createValue() is called exactly once when get() is called for the first time.

LazyValue instances are thread safe.

Constructor Summary

Constructors

Constructor and Description
LazyValue()

Method Summary

Modifier and Type	Method and Description
protected abstract T	createValue() Factory method called to create the value on an as need basis.
T	get() Get value.
boolean	hasValue()

Methods inherited from class java.lang.Object

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

Constructor Detail

LazyValue

public LazyValue()

Method Detail

createValue

protected abstract T createValue()

Factory method called to create the value on an as need basis.

Returns:

a new instance for T.

hasValue

public boolean hasValue()

Returns:

true iff get() has been called at least once.

get

public T get()

Get value. Calls createValue() if called for the first time.

Specified by:

get in interface Supplier<T>

Returns:

the value