refactor(Key): extract KeyRegistry to remove the need in `Key.clear`

modules/di/src/key.js

@@ -2,8 +2,6 @@ import {KeyMetadataError} from './exceptions';
 import {MapWrapper, Map} from 'facade/collection';
 import {FIELD, int, isPresent} from 'facade/lang';
 
-var _allKeys = MapWrapper.create();
-
 export class Key {
   @FIELD('final token')
   @FIELD('final id:int')
@@ -14,18 +12,6 @@ export class Key {
     this.metadata = null;
   }
 
-  static get(token):Key {
-    if (token instanceof Key) return token;
-
-    if (MapWrapper.contains(_allKeys, token)) {
-      return MapWrapper.get(_allKeys, token);
-    }
-
-    var newKey = new Key(token, Key.numberOfKeys);
-    MapWrapper.set(_allKeys, token, newKey);
-    return newKey;
-  }
-
   static setMetadata(key:Key, metadata):Key {
     if (isPresent(key.metadata) && key.metadata !== metadata) {
       throw new KeyMetadataError();
@@ -34,11 +20,36 @@ export class Key {
     return key;
   }
 
-  static clear() {
+  static get(token):Key {
-    _allKeys = MapWrapper.create();
+    return _globalKeyRegistry.get(token);
   }
 
   static get numberOfKeys():int {
-    return MapWrapper.size(_allKeys);
+    return _globalKeyRegistry.numberOfKeys;
   }
 }
+
+export class KeyRegistry {
+  @FIELD('final _allKeys:Map')
+  constructor() {
+    this._allKeys = MapWrapper.create();
+  }
+
+  get(token):Key {
+    if (token instanceof Key) return token;
+
+    if (MapWrapper.contains(this._allKeys, token)) {
+      return MapWrapper.get(this._allKeys, token);
+    }
+
+    var newKey = new Key(token, Key.numberOfKeys);
+    MapWrapper.set(this._allKeys, token, newKey);
+    return newKey;
+  }
+
+  get numberOfKeys():int {
+    return MapWrapper.size(this._allKeys);
+  }
+}
+
+var _globalKeyRegistry = new KeyRegistry();

modules/di/test/di/key_spec.js

@@ -1,27 +1,29 @@
 import {describe, it, expect, beforeEach} from 'test_lib/test_lib';
-import {Key} from 'di/di';
+import {Key, KeyRegistry} from 'di/di';
 
 export function main() {
   describe("key", function () {
+    var registry;
+
     beforeEach(function () {
-      Key.clear();
+      registry = new KeyRegistry();
     });
 
     it('should be equal to another key if type is the same', function () {
-      expect(Key.get('car')).toBe(Key.get('car'));
+      expect(registry.get('car')).toBe(registry.get('car'));
     });
 
     it('should not be equal to another key if types are different', function () {
-      expect(Key.get('car')).not.toBe(Key.get('porsche'));
+      expect(registry.get('car')).not.toBe(registry.get('porsche'));
     });
 
     it('should return the passed in key', function () {
-      expect(Key.get(Key.get('car'))).toBe(Key.get('car'));
+      expect(registry.get(registry.get('car'))).toBe(registry.get('car'));
     });
 
     describe("metadata", function () {
       it("should assign metadata to a key", function () {
-        var key = Key.get('car');
+        var key = registry.get('car');
 
         Key.setMetadata(key, "meta");
 
@@ -29,7 +31,7 @@ export function main() {
       });
 
       it("should allow assigning the same metadata twice", function () {
-        var key = Key.get('car');
+        var key = registry.get('car');
 
         Key.setMetadata(key, "meta");
         Key.setMetadata(key, "meta");
@@ -38,7 +40,7 @@ export function main() {
       });
 
       it("should throw when assigning different metadata", function () {
-        var key = Key.get('car');
+        var key = registry.get('car');
 
         Key.setMetadata(key, "meta1");