From 378c95baa3b4eedde968c86e6420bc61372b7d2a Mon Sep 17 00:00:00 2001
From: James Strachan <james.strachan@gmail.com>
Date: Mon, 16 Apr 2012 17:52:02 +0100
Subject: [PATCH] added a linkedMap() function to help create LinkedHashMap
 objects to maintain map insertion order

---
 libraries/stdlib/src/kotlin/JUtil.kt | 23 ++++++++++++++++++++++-
 libraries/stdlib/test/MapTest.kt     | 18 ++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/libraries/stdlib/src/kotlin/JUtil.kt b/libraries/stdlib/src/kotlin/JUtil.kt
index 2b0b5e39b5c..e744fd26494 100644
--- a/libraries/stdlib/src/kotlin/JUtil.kt
+++ b/libraries/stdlib/src/kotlin/JUtil.kt
@@ -30,7 +30,7 @@ public inline fun sortedSet<T>(vararg values: T) : TreeSet<T> = values.to(TreeSe
  * @includeFunctionBody ../../test/MapTest.kt createUsingTuples
  */
 public inline fun <K,V> hashMap(vararg values: #(K,V)): HashMap<K,V> {
-    val answer = HashMap<K,V>()
+    val answer = HashMap<K,V>(values.size)
     /**
         TODO replace by this simpler call when we can pass vararg values into other methods
         answer.putAll(values)
@@ -44,6 +44,8 @@ public inline fun <K,V> hashMap(vararg values: #(K,V)): HashMap<K,V> {
 /**
  * Returns a new [[SortedMap]] populated with the given tuple values where the first value in each tuple
  * is the key and the second value is the value
+ *
+ * @includeFunctionBody ../../test/MapTest.kt createSortedMap
  */
 public inline fun <K,V> sortedMap(vararg values: #(K,V)): SortedMap<K,V> {
     val answer = TreeMap<K,V>()
@@ -57,6 +59,25 @@ public inline fun <K,V> sortedMap(vararg values: #(K,V)): SortedMap<K,V> {
     return answer
 }
 
+/**
+ * Returns a new [[LinkedHashMap]] populated with the given tuple values where the first value in each tuple
+ * is the key and the second value is the value. This map preserves insertion order so iterating through
+ * the map's entries will be in the same order
+ *
+ * @includeFunctionBody ../../test/MapTest.kt createLinkedHashMap
+ */
+public inline fun <K,V> linkedMap(vararg values: #(K,V)): LinkedHashMap<K,V> {
+    val answer = LinkedHashMap<K,V>(values.size)
+    /**
+        TODO replace by this simpler call when we can pass vararg values into other methods
+        answer.putAll(values)
+    */
+    for (v in values) {
+        answer.put(v._1, v._2)
+    }
+    return answer
+}
+
 
 val Collection<*>.indices : IntRange
     get() = 0..size-1
diff --git a/libraries/stdlib/test/MapTest.kt b/libraries/stdlib/test/MapTest.kt
index 1bb2115e556..9b149f2d370 100644
--- a/libraries/stdlib/test/MapTest.kt
+++ b/libraries/stdlib/test/MapTest.kt
@@ -119,6 +119,24 @@ class MapTest {
         assertEquals(2, map.get("b"))
     }
 
+    test fun createLinkedMap() {
+        val map = linkedMap(#("c", 3), #("b", 2), #("a", 1))
+        assertEquals(3, map.size)
+        assertEquals(1, map.get("a"))
+        assertEquals(2, map.get("b"))
+        assertEquals(3, map.get("c"))
+        assertEquals(arrayList("c", "b", "a"), map.keySet().toList())
+    }
+
+    test fun createSortedMap() {
+        val map = sortedMap(#("c", 3), #("b", 2), #("a", 1))
+        assertEquals(3, map.size)
+        assertEquals(1, map.get("a"))
+        assertEquals(2, map.get("b"))
+        assertEquals(3, map.get("c"))
+        assertEquals(arrayList("a", "b", "c"), map.keySet()!!.toList())
+    }
+
     /**
     TODO
     test case for http://youtrack.jetbrains.com/issue/KT-1773