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Delegates.observable and vetoable inline their lambda parameters into ObservableProperty implementation.

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ObservableProperty made abstract.
#KT-5388
This commit is contained in:
Ilya Gorbunov
2015-06-23 20:39:14 +03:00
parent 9dbc4e4eef
commit cb9d9cb77d
1 changed files with 38 additions and 30 deletions
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libraries/stdlib/src/kotlin/properties/Delegation.kt
+38 -30
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@@ -35,26 +35,28 @@ public object Delegates {
/**
* Returns a property delegate for a read/write property that calls a specified callback function when changed.
* @param initial the initial value of the property.
* @param initialValue the initial value of the property.
* @param onChange the callback which is called after the change of the property is made. The value of the property
* has already been changed when this callback is invoked.
*/
public fun observable<T>(initial: T, onChange: (property: PropertyMetadata, oldValue: T, newValue: T) -> Unit): ReadWriteProperty<Any?, T> {
return ObservableProperty<T>(initial, afterChange = onChange)
}
public inline fun observable<T>(initialValue: T, inlineOptions(InlineOption.ONLY_LOCAL_RETURN) onChange: (property: PropertyMetadata, oldValue: T, newValue: T) -> Unit):
ReadWriteProperty<Any?, T> = object : ObservableProperty<T>(initialValue) {
override fun afterChange(property: PropertyMetadata, oldValue: T, newValue: T) = onChange(property, oldValue, newValue)
}
/**
* Returns a property delegate for a read/write property that calls a specified callback function when changed,
* allowing the callback to veto the modification.
* @param initial the initial value of the property.
* @param initialValue the initial value of the property.
* @param onChange the callback which is called before a change to the property value is attempted.
* The value of the property hasn't been changed yet, when this callback is invoked.
* If the callback returns `true` the value of the property is being set to the new value,
* and if the callback returns `false` the new value is discarded and the property remains its old value.
*/
public fun vetoable<T>(initial: T, onChange: (property: PropertyMetadata, oldValue: T, newValue: T) -> Boolean): ReadWriteProperty<Any?, T> {
return ObservableProperty<T>(initial, beforeChange = onChange)
}
public inline fun vetoable<T>(initialValue: T, inlineOptions(InlineOption.ONLY_LOCAL_RETURN) onChange: (property: PropertyMetadata, oldValue: T, newValue: T) -> Boolean):
ReadWriteProperty<Any?, T> = object : ObservableProperty<T>(initialValue) {
override fun beforeChange(property: PropertyMetadata, oldValue: T, newValue: T): Boolean = onChange(property, oldValue, newValue)
}
/**
* Returns a property delegate for a read/write property that stores its value in a map, using the property name
@@ -112,39 +114,45 @@ private class NotNullVar<T: Any>() : ReadWriteProperty<Any?, T> {
}
}
deprecated("Use Delegates.vetoable() instead or construct implementation of abstract ObservableProperty", ReplaceWith("Delegates.vetoable(initialValue, onChange)"))
public fun ObservableProperty<T>(initialValue: T, onChange: (property: PropertyMetadata, oldValue: T, newValue: T) -> Boolean): ObservableProperty<T> =
object : ObservableProperty<T>(initialValue) {
override fun beforeChange(property: PropertyMetadata, oldValue: T, newValue: T): Boolean = onChange(property, oldValue, newValue)
}
/**
* Implements a property delegate for a read/write property that calls a specified callback function when changed.
* Implements the core logic of a property delegate for a read/write property that calls callback functions when changed.
* @param initialValue the initial value of the property.
* @param beforeChange the callback which is called before a change to the property value is attempted.
* The value of the property hasn't been changed yet, when this callback is invoked.
* If the callback returns `true` the value of the property is being set to the new value,
* and if the callback returns `false` the new value is discarded and the property remains its old value.
* @param afterChange the callback which is called after the change of the property is made. The value of the property
* has already been changed when this callback is invoked.
*/
public class ObservableProperty<T>(
initialValue: T,
private val beforeChange: ((property: PropertyMetadata, oldValue: T, newValue: T) -> Boolean)? = null,
private val afterChange: ((property: PropertyMetadata, oldValue: T, newValue: T) -> Unit)? = null
) : ReadWriteProperty<Any?, T> {
public abstract class ObservableProperty<T>(initialValue: T) : ReadWriteProperty<Any?, T> {
private var value = initialValue
/**
* The callback which is called before a change to the property value is attempted.
* The value of the property hasn't been changed yet, when this callback is invoked.
* If the callback returns `true` the value of the property is being set to the new value,
* and if the callback returns `false` the new value is discarded and the property remains its old value.
*/
protected open fun beforeChange(property: PropertyMetadata, oldValue: T, newValue: T): Boolean = true
/**
* The callback which is called after the change of the property is made. The value of the property
* has already been changed when this callback is invoked.
*/
protected open fun afterChange (property: PropertyMetadata, oldValue: T, newValue: T): Unit {}
public override fun get(thisRef: Any?, property: PropertyMetadata): T {
return value
}
public override fun set(thisRef: Any?, property: PropertyMetadata, value: T) {
if (beforeChange == null && afterChange == null) {
this.value = value
}
else {
val oldValue = this.value
if (beforeChange != null && !(beforeChange)(property, oldValue, value)) {
return
}
this.value = value
if (afterChange != null) (afterChange)(property, oldValue, value)
val oldValue = this.value
if (!beforeChange(property, oldValue, value)) {
return
}
this.value = value
afterChange(property, oldValue, value)
}
}