Factored out a default map implementation that ...

Factored out a default map implementation that implements all map
operations in terms of three simple operations: find, add, and remove.

3 files changed, 82 insertions, 30 deletions

diff --git a/sources/scala/HashMap.scala b/sources/scala/HashMap.scala
index 4aa4bc7ab5..18af2a174e 100644
--- a/sources/scala/HashMap.scala
+++ b/sources/scala/HashMap.scala
@@ -11,36 +11,9 @@ package scala;
 
 /** I promise, there will be some documentation soon! :-) Matthias
  */
-class HashMap[A, B] extends MutableMap[A, B] with HashTable[A] {
-
-    def get(key: A) = findEntry(key) match {
-        case None => None
-        case Some(e) => Some(e.value);
-    }
-
-    def update(key: A, value: B) = findEntry(key) match {
-        case None => addEntry(new Entry(key, value));
-        case Some(e) => e.value = value;
-    }
-
-    def remove(key: A) = {
-        val old = apply(key);
-        removeEntry(key);
-        old;
-    }
-
-    def elements = new Iterator[Pair[A, B]] {
-        val iter = entries;
-        def hasNext = iter.hasNext;
-        def next = iter.next.toPair;
-    }
-
-    protected class Entry(k: A, v: B) {
-        def key = k;
-        var value = v;
-        def toPair = Pair(k, value);
-        override def toString() = k.toString() + " -> " + value;
-    }
+class HashMap[A, B] extends MutableMap[A, B]
+                    with HashTable[A]
+                    with MapImpl[A, B] {
 
     protected def entryKey(e: Entry) = e.key;
 }
diff --git a/sources/scala/ListMap.scala b/sources/scala/ListMap.scala
new file mode 100644
index 0000000000..fa4a556607
--- /dev/null
+++ b/sources/scala/ListMap.scala
@@ -0,0 +1,29 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2003, LAMP/EPFL                  **
+**  __\ \/ /__/ __ |/ /__/ __ |                                         **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+** $Id$
+\*                                                                      */
+
+package scala;
+
+
+class ListMap[A, B] extends MutableMap[A, B]
+                    with MapImpl[A, B] {
+
+	var xs: List[Entry] = Nil;
+
+    def size: Int = xs.length;
+
+    def clear: Unit = { xs = Nil; }
+
+ 	protected def findEntry(key: A) = xs find {e => e.key == key};
+
+	protected def addEntry(e: Entry) = { xs = e :: xs; }
+
+    protected def removeEntry(key: A) = { xs = xs filter {e => e.key != key}; }
+
+	protected def entries = xs.elements;
+}
diff --git a/sources/scala/MapImpl.scala b/sources/scala/MapImpl.scala
new file mode 100644
index 0000000000..0082f102b9
--- /dev/null
+++ b/sources/scala/MapImpl.scala
@@ -0,0 +1,50 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2003, LAMP/EPFL                  **
+**  __\ \/ /__/ __ |/ /__/ __ |                                         **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+** $Id$
+\*                                                                      */
+
+package scala;
+
+
+trait MapImpl[A, B] extends MutableMap[A, B] {
+
+	protected def findEntry(key: A): Option[Entry];
+
+	protected def addEntry(e: Entry): Unit;
+
+    protected def removeEntry(key: A): Unit;
+
+    protected def entries: Iterator[Entry];
+
+    def get(key: A) = findEntry(key) match {
+        case None => None
+        case Some(e) => Some(e.value);
+    }
+
+    def update(key: A, value: B) = findEntry(key) match {
+        case None => addEntry(new Entry(key, value));
+        case Some(e) => e.value = value;
+    }
+
+    def remove(key: A) = findEntry(key) match {
+    	case None => null;
+    	case Some(e) => removeEntry(key); e.value;
+    }
+
+    def elements = new Iterator[Pair[A, B]] {
+        val iter = entries;
+        def hasNext = iter.hasNext;
+        def next = iter.next.toPair;
+    }
+
+    protected class Entry(k: A, v: B) {
+        def key = k;
+        var value = v;
+        def toPair = Pair(k, value);
+        override def toString() = k.toString() + " -> " + value;
+    }
+}