From c9959a10f9684f0ef10ac94bfecfc4eded6144f4 Mon Sep 17 00:00:00 2001
From: James Strachan <james.strachan@gmail.com>
Date: Tue, 20 Dec 2011 18:06:58 +0000
Subject: [PATCH] added a couple of helper methods to Map to be able look up in
 a Map with function to provide a default value

---
 stdlib/ktSrc/JavaUtil.kt | 36 ++++++++++++++++++++++++++++++++++++
 testlib/test/MapTest.kt  | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+)
 create mode 100644 testlib/test/MapTest.kt

diff --git a/stdlib/ktSrc/JavaUtil.kt b/stdlib/ktSrc/JavaUtil.kt
index cae1b643c5c..b71427a49e0 100644
--- a/stdlib/ktSrc/JavaUtil.kt
+++ b/stdlib/ktSrc/JavaUtil.kt
@@ -195,3 +195,39 @@ val <T> List<T>.tail : T?
 val <T> List<T>.last : T?
   get() = this.tail
 
+
+
+// Map APIs
+/** Returns the size of the map */
+/* TODO get redeclaration errors
+val Map<*,*>.size : Int
+    get() = size()
+*/
+
+/** Returns true if this map is empty */
+/* TODO get redeclaration errors
+val Map<*,*>.empty : Boolean
+    get() = isEmpty()
+*/
+
+/** Returns the value for the given key or returns the result of the defaultValue function if there was no entry for the given key */
+inline fun <K,V> java.util.Map<K,V>.getOrElse(key: K, defaultValue: fun(): V) : V {
+  val current = this.get(key)
+  if (current != null) {
+    return current
+  } else {
+    return defaultValue()
+  }
+}
+
+/** Returns the value for the given key or the result of the defaultValue function is put into the map for the given value and returned */
+inline fun <K,V> java.util.Map<K,V>.getOrElseUpdate(key: K, defaultValue: fun(): V) : V {
+  val current = this.get(key)
+  if (current != null) {
+    return current
+  } else {
+    val answer = defaultValue()
+    this.put(key, answer)
+    return answer
+  }
+}
diff --git a/testlib/test/MapTest.kt b/testlib/test/MapTest.kt
new file mode 100644
index 00000000000..ba0a9c4ee6d
--- /dev/null
+++ b/testlib/test/MapTest.kt
@@ -0,0 +1,35 @@
+namespace test.collections
+
+import std.test.*
+
+// TODO can we avoid importing all this stuff by default I wonder?
+// e.g. making println and the collection builder methods public by default?
+import std.*
+import std.io.*
+import std.util.*
+import java.util.*
+
+class MapTest() : TestSupport() {
+  val data = HashMap<String, Int>()
+
+  fun testGetOrElse() {
+    val a = data.getOrElse("foo"){2}
+    assertEquals(2, a)
+
+    val b = data.getOrElse("foo"){3}
+    assertEquals(3, b)
+
+    // TODO should be able to miss the () off of size
+    assertEquals(0, data.size())
+  }
+
+  fun testGetOrElseUpdate() {
+    val a = data.getOrElseUpdate("foo"){2}
+    assertEquals(2, a)
+
+    val b = data.getOrElseUpdate("foo"){3}
+    assertEquals(2, b)
+
+    assertEquals(1, data.size())
+  }
+}
\ No newline at end of file