1 files changed, 47 insertions, 0 deletions
diff --git a/sources/ch/epfl/lamp/util/StackedMap.java b/sources/ch/epfl/lamp/util/StackedMap.java
new file mode 100644
index 0000000000..171976d7a0
--- /dev/null
+++ b/sources/ch/epfl/lamp/util/StackedMap.java
@@ -0,0 +1,47 @@
+package ch.epfl.lamp.util;
+
+import java.util.*;
+
+/**
+ * A stack of hash maps.
+ *
+ * @author Michel Schinz
+ * @version 1.0
+ */
+
+public class StackedHashMap extends AbstractMap implements Map {
+    protected LinkedList/*<HashMap>*/ maps = new LinkedList();
+    protected HashMap topmostMap = new HashMap();
+
+    public void push() {
+        maps.addFirst(topmostMap);
+        topmostMap = new HashMap(topmostMap);
+    }
+
+    public void push(Map map) {
+        push();
+        topmostMap.putAll(map);
+    }
+
+    public void pop() {
+        topmostMap = (HashMap)maps.removeFirst();
+    }
+
+    public Object put(Object key, Object value) {
+        return topmostMap.put(key, value);
+    }
+
+    public void putAll(Object[] keys, Object[] values) {
+        assert keys.length == values.length;
+        for (int i = 0; i < keys.length; ++i)
+            topmostMap.put(keys[i], values[i]);
+    }
+
+    public Object get(Object key) {
+        return topmostMap.get(key);
+    }
+
+    public Set entrySet() {
+        return topmostMap.entrySet();
+    }
+}