Class ScopedValue.Carrier
- Enclosing class:
ScopedValuePREVIEW<T>
Carrier is a preview API of the Java platform.
A Carrier is used to accumulate mappings so that an operation (a Runnable or ScopedValue.CallableOpPREVIEW) can be executed with all scoped values in the
mapping bound to values. The following example runs an operation with k1
bound (or rebound) to v1, and k2 bound (or rebound) to v2.
A Carrier is immutable and thread-safe. The where method returns a new Carrier object,
it does not mutate an existing mapping.
Unless otherwise specified, passing a null argument to a method in
this class will cause a NullPointerException to be thrown.
- Since:
- 21
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Method Summary
Modifier and TypeMethodDescription<R, X extends Throwable>
Rcall(ScopedValue.CallableOpPREVIEW<? extends R, X> op) Calls a value-returning operation with each scoped value in this mapping bound to its value in the current thread.<T> Tget(ScopedValuePREVIEW<T> key) Returns the value of aScopedValuePREVIEW in this mapping.voidRuns an operation with each scoped value in this mapping bound to its value in the current thread.where(ScopedValuePREVIEW<T> key, T value) Returns a newCarrierwith the mappings from this carrier plus a new mapping fromkeytovalue.
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Method Details
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where
Returns a newCarrierwith the mappings from this carrier plus a new mapping fromkeytovalue. If this carrier already has a mapping for the scoped valuekeythen it will map to the newvalue. The current carrier is immutable, so it is not changed by this method.- Type Parameters:
T- the type of the value- Parameters:
key- theScopedValuekeyvalue- the value, can benull- Returns:
- a new
Carrierwith the mappings from this carrier plus the new mapping
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get
Returns the value of aScopedValuePREVIEW in this mapping.- Type Parameters:
T- the type of the value- Parameters:
key- theScopedValuekey- Returns:
- the value
- Throws:
NoSuchElementException- if the key is not present in this mapping
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call
Calls a value-returning operation with each scoped value in this mapping bound to its value in the current thread. When the operation completes (normally or with an exception), each scoped value in the mapping will revert to being unbound, or revert to its previous value when previously bound, in the current thread. Ifopcompletes with an exception then it propagated by this method.Scoped values are intended to be used in a structured manner. If code invoked directly or indirectly by the operation creates a
StructuredTaskScopePREVIEW but does not closePREVIEW it, then it is detected as a structure violation when the operation completes (normally or with an exception). In that case, the underlying construct of theStructuredTaskScopeis closed andStructureViolationExceptionPREVIEW is thrown.- Type Parameters:
R- the type of the result of the operationX- type of the exception thrown by the operation- Parameters:
op- the operation to run- Returns:
- the result
- Throws:
StructureViolationExceptionPREVIEW- if a structure violation is detectedX- ifopcompletes with an exception- Since:
- 23
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run
Runs an operation with each scoped value in this mapping bound to its value in the current thread. When the operation completes (normally or with an exception), each scoped value in the mapping will revert to being unbound, or revert to its previous value when previously bound, in the current thread. Ifopcompletes with an exception then it propagated by this method.Scoped values are intended to be used in a structured manner. If code invoked directly or indirectly by the operation creates a
StructuredTaskScopePREVIEW but does not closePREVIEW it, then it is detected as a structure violation when the operation completes (normally or with an exception). In that case, the underlying construct of theStructuredTaskScopeis closed andStructureViolationExceptionPREVIEW is thrown.- Parameters:
op- the operation to run- Throws:
StructureViolationExceptionPREVIEW- if a structure violation is detected
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Carrierwhen preview features are enabled.