Valuable<Output> class abstract

Main class Valuable

This class inherits of ChangeNotifier to manage its events.

It's importance to notice that the dispose of this object has to be done to avoid memory leaks and useless remaining references. For these reasons, the method dispose should be called when the object isn't used anymore.

It's possible to know if the Valuable object is still mounted by testing getter isMounted. When isMounted becomes false, it can't back to true, this object will die. Furthermore, it's possible to listen for the object unmounting by using the method listenDispose.

This class defines 2 factories to build simpler Valuable:

• Valuable.value represent a Valuable at its simplest form : a value. No function, no dependencies, just a value that would be returned by getValue
• Valuable.computed which is more complex but even more powerful. Indeed, the valuer param is a function, where Valuable calculate its self value. In fact it's even possible to depends on other Valuables, whose values are possibly changeable. When these Valuable values change, our Valuable is notified, and notify at its turn to be read again.

Lastly, the most useful method, getValue. Simple as its name, this method returns the current value of the Valuable (final or calculated). In addition, it's even possible to pass a ValuableContext to specify the context where the value is needed.

Inheritance

• Object
• ChangeNotifier
• Valuable

Implementers

• FutureValuable
• HistorizedValuable
• StatefulValuable
• StreamValuable
• ValuableBoolGroup
• ValuableCompare
• ValuableIf
• ValuableLinker
• ValuableNumOperation
• ValuableStringOperation
• ValuableSwitch

Available Extensions

• BoolOperators
• ListenableValuable
• ListOperators
• NumOperators
• StringOperators
• ValuableFutureExtension
• ValuableStreamExtension
• WidgetValuable

Constructors

Valuable({bool evaluateWithContext = false})

Valuable.byValuer(ValuableParentWatcher<Output> valuer, {bool evaluateWithContext = false})

Replace by Valuable.computed.

factory

Valuable.computed(ValuableParentWatcher<Output> computation, {bool evaluateWithContext = false})

Factory Valuable.computed to build a Valuable that calculate its own value through a function.

factory

Valuable.listenable(ValueListenable<Output> listenable)

Factory Valuable.listenable to build a Valuable that listen to a ValueListenable and provide its value

factory

Valuable.value(Output value)

Factory Valuable.value to build a simple Valuable on a final value

factory

Properties

hashCode → int

The hash code for this object.

no setter, inherited

hasListeners → bool

Whether any listeners are currently registered.

no setter, inherited

isMounted → bool

Returns if this object is still mounted

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

valuableContext → ValuableContext?

no setter, inherited

valueCache → _ValueCache

final

Methods

addListener(VoidCallback listener) → void

Register a closure to be called when the object changes.

inherited

cleanWatched() → void

inherited

dispose() → void

Should be called to clean all links to other Valuables, and all the rest

override

equals(dynamic other) → Valuable<bool>

Compare with a value that type is Output or another Valuable

getValue([ValuableContext? context = const ValuableContext()]) → Output

Get the current value of the Valuable

getValueDefinition(bool reevaluatingNeeded, [ValuableContext? context = const ValuableContext()]) → Output

This method should be redefined in ever sub-classes to determine how works the method getValue

historize() → HistorizedValuable<Output>

Build an HistorizedValuable based on this Valuable

listenDispose(VoidCallback onDispose) → void

Allows to be notified when this Valuable is disposed

map<Other>(Other toElement(Output)) → Valuable<Other>

A method to map a Valuable from Output to Other

markToReevaluate() → void

Mark the valuable to be reevaluated

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

notEquals(dynamic other) → Valuable<bool>

Compare with a value that type is Output or another Valuable

notifyListeners() → void

Call all the registered listeners.

inherited

onValuableChange() → void

Called when a Valuable notify a change.

removeListener(VoidCallback listener) → void

Remove a previously registered closure from the list of closures that are notified when the object changes.

inherited

toString() → String

A string representation of this object.

inherited

unwatch(Valuable valuable) → void

Remove listener on the valuable, that may change scope, or that about to be disposed Internal purpose

inherited

watch<T>(Valuable<T> valuable, {ValuableContext? valuableContext, ValuableWatcherSelector<T>? selector}) → T

Watch a valuable, that eventually change

Operators

operator <(dynamic other) → Valuable<bool>

Compare with a value that type is Output or another Valuable

operator <=(dynamic other) → Valuable<bool>

Compare with a value that type is Output or another Valuable

operator ==(Object other) → bool

The equality operator.

inherited

operator >(dynamic other) → Valuable<bool>

Compare with a value that type is Output or another Valuable

operator >=(dynamic other) → Valuable<bool>

Compare with a value that type is Output or another Valuable

Static Methods

listenableComputed<L extends Listenable, Output>(L listenable, Output computation(L listenable)) → Valuable<Output>

Factory Valuable.listenableComputed to build a Valuable that listen to a Listenable and provide a value by computation