Simple extensions to delegate readonly property to Map and read-write property to MutableMap without delegate wrappers.
Delegation to map with custom key selector by map accessors.
This commit is contained in:
Ilya Gorbunov
@@ -0,0 +1,103 @@
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package kotlin.properties
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import kotlin.platform.platformName
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// extensions for Map and MutableMap
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public fun <V> Map<in String, *>.get(thisRef: Any?, property: PropertyMetadata): V {
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val value = this.get(property.name)
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if (value == null && !containsKey(property.name))
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defaultValueProvider(thisRef, property.name)
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return value as V
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}
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platformName("getVar")
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public fun <V> MutableMap<in String, in V>.get(thisRef: Any?, property: PropertyMetadata): V {
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val value = this.get(property.name)
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if (value == null && !containsKey(property.name))
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defaultValueProvider(thisRef, property.name)
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return value as V
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}
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public fun <V> MutableMap<in String, in V>.set(thisRef: Any?, property: PropertyMetadata, value: V) {
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this.put(property.name, value)
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}
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// Map accessors
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public interface MapAccessor<KMap, in KAccess, out V>
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{
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public val map: Map<in KMap, V>
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/** Returns `true` if the map contains the specified [key]. */
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public fun containsKey(key: KAccess): Boolean
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/** Returns the value corresponding to the given [key], or the value provided with [default] function if such a key is not present in the map. */
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public fun getOrDefault(key: KAccess): V
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public open fun withDefault<V>(default: (KMap) -> V): MapAccessor<KMap, KAccess, V>
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}
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public interface MutableMapAccessor<KMap, in KAccess, V>: MapAccessor<KMap, KAccess, V> {
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public override val map: MutableMap<in KMap, V>
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/** Associates the specified [value] with the specified [key] in the map. */
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public fun put(key: KAccess, value: V): V?
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public override fun <V> withDefault(default: (KMap) -> V): MutableMapAccessor<KMap, KAccess, V>
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}
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public fun <V> Map<in String, V>.forProperties(): MapAccessor<String, PropertyMetadata, V> = MapAccessorImpl(this, defaultKeyProvider)
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// todo: inline keyselector into anonymous object
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public fun <K, V> Map<in K, V>.forProperties(keySelector: (PropertyMetadata) -> K): MapAccessor<K, PropertyMetadata, V> = MapAccessorImpl(this, keySelector)
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public fun <V> MutableMap<in String, V>.forProperties(): MutableMapAccessor<String, PropertyMetadata, V> = MutableMapAccessorImpl(this, defaultKeyProvider)
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// todo: inline keyselector into anonymous object
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public fun <K, V> MutableMap<in K, V>.forProperties(keySelector: (PropertyMetadata) -> K): MutableMapAccessor<K, PropertyMetadata, V> = MutableMapAccessorImpl(this, keySelector)
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// extensions to delegate properties to MapAccessors
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public fun <K, V> MapAccessor<K, PropertyMetadata, V>.get(thisRef: Any?, property: PropertyMetadata): V = this.getOrDefault(property)
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platformName("getVar")
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public fun <K, V> MutableMapAccessor<K, PropertyMetadata, in V>.get(thisRef: Any?, property: PropertyMetadata): V = this.getOrDefault(property) as V
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public fun <K, V> MutableMapAccessor<K, PropertyMetadata, in V>.set(thisRef: Any?, property: PropertyMetadata, value: V) {
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this.put(property, value)
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}
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// MapAccessor implementations
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private open class MapAccessorImpl<KMap, in KAccess, out V>(public override val map: Map<in KMap, V>, public val transform: (KAccess) -> KMap, public val default: (KMap) -> V = { k1 -> defaultValueProvider(map, k1) })
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: MapAccessor<KMap, KAccess, V> {
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override fun containsKey(key: KAccess): Boolean = map.containsKey(transform(key))
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override fun getOrDefault(key: KAccess): V {
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val key1 = transform(key)
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val value = map.get(key1)
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if (value == null && !map.containsKey(key1))
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return default(key1)
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else
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return value as V
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}
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override fun withDefault<V>(default: (KMap) -> V): MapAccessor<KMap, KAccess, V> = MapAccessorImpl<KMap, KAccess, V>(map as Map<in KMap, V>, transform, default)
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}
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private class MutableMapAccessorImpl<KMap, in KAccess, V>(public override val map: MutableMap<in KMap, V>, transform: (KAccess) -> KMap, default: (KMap) -> V = { k1 -> defaultValueProvider(map, k1) })
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: MapAccessorImpl<KMap, KAccess, V>(map, transform, default), MutableMapAccessor<KMap, KAccess, V> {
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override fun put(key: KAccess, value: V): V? = map.put(transform(key), value)
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override fun <V> withDefault(default: (KMap) -> V): MutableMapAccessor<KMap, KAccess, V> = MutableMapAccessorImpl<KMap, KAccess, V>(map as MutableMap<in KMap, V>, transform, default)
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}
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@@ -0,0 +1,107 @@
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package test.properties.delegation
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import kotlin.properties.*
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import kotlin.test.*
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import org.junit.Test as test
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class ValByMapExtensionsTest {
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val map: Map<String, String> = hashMapOf("a" to "all", "b" to "bar", "c" to "code")
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val genericMap = mapOf<String, Any?>("i" to 1, "x" to 1.0)
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val a: String by map
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val b: String by map
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val c: Any by map
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val d: String? by map
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val e: Any by map
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val i: Int by genericMap
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val x: Double by genericMap
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test fun doTest() {
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assertEquals("all", a)
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assertEquals("bar", b)
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assertEquals("code", c)
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assertEquals(1, i)
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assertEquals(1.0, x)
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fails { d }
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}
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}
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class VarByMapExtensionsTest {
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val map = hashMapOf<String, Any?>("a" to "all", "b" to null, "c" to 1, "xProperty" to 1.0)
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val map2: MutableMap<String, CharSequence> = hashMapOf("a2" to "all")
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var a: String by map
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var b: Any? by map
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var c: Int by map
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var d: String? by map
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var a2: String by map2
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//var x: Int by map2 // prohibited by type system
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test fun doTest() {
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assertEquals("all", a)
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assertEquals(null, b)
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assertEquals(1, c)
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c = 2
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assertEquals(2, c)
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assertEquals(2, map["c"])
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map["c"] = "string"
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fails { c }
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map["a"] = null
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a // fails { a } // does not fail due to KT-8135
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fails { d }
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map["d"] = null
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assertEquals(null, d)
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}
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}
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class ValByMapAccessorExtensionsTest {
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val map: Map<String, String> = mapOf("a" to "all", "b" to "bar", "c" to "code")
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val genericMap = mapOf<String, Any?>("i" to 1, "x" to 1.0)
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val mapAccessor = map.forProperties { it.name.take(1) }
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val genericMapAccessor = genericMap.forProperties { it.name.take(1) }
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val cProperty by mapAccessor
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val xProperty by genericMapAccessor
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val zNoDefault by genericMapAccessor
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val zProperty by genericMapAccessor.withDefault { 1 }
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test fun doTest() {
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assertEquals("code", cProperty)
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assertEquals(1.0, xProperty)
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assertEquals(1, zProperty)
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fails { zNoDefault }
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}
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}
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class VarByMapAccessorExtensionsTest {
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val map = hashMapOf<String, Any?>("xProperty" to 1.0)
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val mapAccessor = map.forProperties { it.name + "Property" }
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var x: Double by mapAccessor.withDefault { 2.0 }
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var z: Int by mapAccessor
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var s: String by mapAccessor
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test fun doTest() {
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assertEquals(1.0, x)
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map.remove("xProperty")
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assertEquals(2.0, x)
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z = 2
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assertEquals(2, z)
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assertEquals(2, map["zProperty"])
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fails { s }
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map["sProperty"] = null
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s // fails { s } // does not fail due to KT-8135
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}
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}
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@@ -3,6 +3,7 @@ package test.properties.delegation
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import org.junit.Test as test
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import java.util.HashMap
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import kotlin.properties.*
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import kotlin.test.*
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class MapDelegationTest(): DelegationTestBase() {
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@@ -81,6 +82,9 @@ class TestMapVarWithDifferentTypes(): WithBox {
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if (b != 11) return "fail at 'b'"
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if (c != B(11)) return "fail at 'c'"
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if (d != null) return "fail at 'd'"
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map["a"] = null
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a // fails { a } // does not fail due to KT-8135
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return "OK"
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}
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}
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