ObservableSet class implementing ObservableState (#148)

1 files changed, 125 insertions, 0 deletions

diff --git a/src/main/kotlin/pl/treksoft/kvision/state/ObservableSet.kt b/src/main/kotlin/pl/treksoft/kvision/state/ObservableSet.kt
new file mode 100644
index 00000000..f7b2f8cd
--- /dev/null
+++ b/src/main/kotlin/pl/treksoft/kvision/state/ObservableSet.kt
@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2017-present Robert Jaros
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package pl.treksoft.kvision.state
+
+/**
+ * Observable set interface.
+ */
+interface ObservableSet<T> : MutableSet<T>, ObservableState<Set<T>> {
+    val onUpdate: MutableCollection<(MutableSet<T>) -> Unit>
+}
+
+/**
+ * Simple observable set implementation.
+ */
+class ObservableSetWrapper<T>(val mutableSet: MutableSet<T> = mutableSetOf()) : MutableSet<T>, ObservableSet<T>,
+    ObservableState<Set<T>> {
+
+    override fun getState(): Set<T> {
+        return this
+    }
+
+    override fun subscribe(observer: (Set<T>) -> Unit): () -> Unit {
+        onUpdate += observer
+        observer(this)
+        return {
+            onUpdate -= observer
+        }
+    }
+
+    override val onUpdate: MutableCollection<(MutableSet<T>) -> Unit> = mutableListOf()
+
+    override val size: Int
+        get() = mutableSet.size
+
+    override fun contains(element: T): Boolean {
+        return mutableSet.contains(element)
+    }
+
+    override fun containsAll(elements: Collection<T>): Boolean {
+        return mutableSet.containsAll(elements)
+    }
+
+    override fun isEmpty(): Boolean {
+        return mutableSet.isEmpty()
+    }
+
+    override fun iterator(): MutableIterator<T> = object : MutableIterator<T> {
+        val inner = mutableSet.iterator()
+        override fun hasNext(): Boolean = inner.hasNext()
+        override fun next(): T = inner.next()
+        override fun remove() {
+            inner.remove()
+            onUpdate.forEach { it(this@ObservableSetWrapper) }
+        }
+    }
+
+    override fun add(element: T): Boolean {
+        val result = mutableSet.add(element)
+        if (result) {
+            onUpdate.forEach { it(this) }
+        }
+        return result
+    }
+
+    override fun addAll(elements: Collection<T>): Boolean {
+        val result = mutableSet.addAll(elements)
+        if (result) {
+            onUpdate.forEach { it(this) }
+        }
+        return result
+    }
+
+    override fun clear() {
+        mutableSet.clear()
+        onUpdate.forEach { it(this) }
+    }
+
+    override fun remove(element: T): Boolean {
+        val result = mutableSet.remove(element)
+        if (result) {
+            onUpdate.forEach { it(this) }
+        }
+        return result
+    }
+
+    override fun removeAll(elements: Collection<T>): Boolean {
+        val result = mutableSet.removeAll(elements)
+        if (result) {
+            onUpdate.forEach { it(this) }
+        }
+        return result
+    }
+
+    override fun retainAll(elements: Collection<T>): Boolean {
+        val result = mutableSet.retainAll(elements)
+        if (result) {
+            onUpdate.forEach { it(this) }
+        }
+        return result
+    }
+}
+
+/**
+ * Creates an instance of ObservableSet<T>
+ */
+fun <T> observableSetOf(vararg items: T) = ObservableSetWrapper(items.toMutableSet())