Lazy<T> class
A Lazy can be used to only initialize a value if it is required.
The _initialize function is only called to initialize the value.
After the first initialization _initialize is only called again if
one of the following cases applies:
reinitializeOnValuereturns true- the last invocation of
_initializehas thrown an error and reinitializeOnError is true - invalidate was called after the last but before the current call to get
If the first get call is still in progress, any subsequent call to get will wait for the result of the first invocation and return the same result.
If _initialize throws an exception every call to get will re-throw this
exception.
Constructors
-
Lazy(FutureOr<
T> _initialize(), {FutureOr<bool> reinitializeOnValue(T value)?, bool reinitializeOnError = false}) -
_initializeis used to initialize the value.reinitializecontrols if a value is reused or initialized again. Ifreinitializereturns true,_initializeis called again to recreate the value.
Properties
- hashCode → int
-
The hash code for this object.
no setterinherited
- isInitialized → bool
-
Returns true if the this Lazy already has a result.
no setter
- reinitializeOnError → bool
-
final
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
Methods
-
get(
) → Future< T> -
Receives the value returned by
initialize. -
invalidate(
) → void -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
toString(
) → String -
A string representation of this object.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited