Class Values
Value provider
factory & utility methods.- Author:
- Marek Potociar
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Method Summary
Modifier and TypeMethodDescriptionstatic <T> Value<T>
Get a new eagerly initializedvalue provider
.static <T> Value<T>
empty()
static <T,
E extends Throwable>
UnsafeValue<T,E> static <T,
E extends Throwable>
LazyUnsafeValue<T,E> lazy
(UnsafeValue<T, E> delegate) Get a new lazily initializedunsafe value provider
.static <T> LazyValue<T>
Get a new lazily initializedvalue provider
.static <T> Value<T>
of
(T value) Get a new constantvalue provider
whoseget()
method always returns the instance supplied to thevalue
parameter.static <T,
E extends Throwable>
UnsafeValue<T,E> throwing
(E throwable) Get a new "throwing"unsafe value provider
whoseget()
method always throws the exception supplied to thethrowable
parameter.static <T,
E extends Throwable>
UnsafeValue<T,E> unsafe
(T value) Get a new constantvalue provider
whoseget()
method always returns the instance supplied to thevalue
parameter.
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Method Details
-
empty
- Type Parameters:
T
- value type.- Returns:
- empty value provider.
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emptyUnsafe
- Type Parameters:
T
- value type.- Returns:
- empty unsafe value provider.
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of
Get a new constantvalue provider
whoseget()
method always returns the instance supplied to thevalue
parameter. In case the supplied value constant isnull
, anempty
value provider is returned.- Type Parameters:
T
- value type.- Parameters:
value
- value instance to be provided.- Returns:
- constant value provider.
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unsafe
Get a new constantvalue provider
whoseget()
method always returns the instance supplied to thevalue
parameter. In case the supplied value constant isnull
, anempty
value provider is returned.- Type Parameters:
T
- value type.- Parameters:
value
- value instance to be provided.- Returns:
- constant value provider.
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throwing
Get a new "throwing"unsafe value provider
whoseget()
method always throws the exception supplied to thethrowable
parameter. In case the supplied throwable isnull
, anNullPointerException
is thrown.- Type Parameters:
T
- value type.E
- exception type.- Parameters:
throwable
- throwable instance to be thrown.- Returns:
- "throwing" unsafe value provider.
- Throws:
NullPointerException
- in case the supplied throwable instance isnull
.
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lazy
Get a new lazily initializedvalue provider
. The value returned by itsget()
method is lazily retrieved during a first call to the method from the supplieddelegate
value provider and is then cached for a subsequent retrieval.The implementation of the returned lazy value provider is thread-safe and is guaranteed to invoke the
get()
method on the supplieddelegate
value provider instance at most once.If the supplied value provider is
null
, anempty
value provider is returned.- Type Parameters:
T
- value type.- Parameters:
delegate
- value provider delegate that will be used to lazily initialize the value provider.- Returns:
- lazily initialized value provider.
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eager
Get a new eagerly initializedvalue provider
. The value returned by itsget()
method is eagerly computed from the supplieddelegate
value provider and is then stored in a final field for a subsequent retrieval.The implementation of the returned eager value provider is thread-safe and is guaranteed to invoke the
get()
method on the supplieddelegate
value provider instance once and only once.If the supplied value provider is
null
, anempty
value provider is returned.- Type Parameters:
T
- value type.- Parameters:
delegate
- value provider delegate that will be used to eagerly initialize the value provider.- Returns:
- eagerly initialized, constant value provider.
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lazy
Get a new lazily initializedunsafe value provider
. The value returned by itsget()
method is lazily retrieved during a first call to the method from the supplieddelegate
value provider and is then cached for a subsequent retrieval.In case the call to underlying
delegate.get()
throws a throwable, the throwable is cached and thrown on all subsequent retrievals.The implementation of the returned lazy value provider is thread-safe and is guaranteed to invoke the
get()
method on the supplieddelegate
value provider instance at most once.If the supplied value provider is
null
, anempty
value provider is returned.- Type Parameters:
T
- value type.- Parameters:
delegate
- value provider delegate that will be used to lazily initialize the value provider.- Returns:
- lazily initialized value provider.
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