Added final keyword for methods

lib/member_builder.js

@@ -75,7 +75,11 @@ exports.buildMethod = function(
     // TODO: We can improve performance by not scanning each one individually
     // every time this method is called
     var prev_data     = scanMembers( members, name, base ),
-        prev      = ( prev_data ) ? prev_data.member : null;
+        prev          = ( prev_data ) ? prev_data.member : null,
+        prev_keywords = ( prev && prev.___$$keywords$$ )
+            ? prev.___$$keywords$$
+            : {}
+    ;
 
     // do not permit private abstract methods (doesn't make sense, since
     // they cannot be inherited/overridden)
@@ -97,6 +101,12 @@ exports.buildMethod = function(
             );
         }
 
+        // final methods cannot be overridden
+        if ( prev_keywords[ 'final' ] )
+        {
+            throw TypeError( "Cannot override final method '" + name + "'" );
+        }
+
         // do not allow overriding concrete methods with abstract
         if ( keywords[ 'abstract' ] && !( util.isAbstractMethod( prev ) ) )
         {

test/test-class_builder-final.js

@@ -0,0 +1,63 @@
+/**
+ * Tests final members
+ *
+ *  Copyright (C) 2010 Mike Gerwitz
+ *
+ *  This file is part of ease.js.
+ *
+ *  ease.js is free software: you can redistribute it and/or modify it under the
+ *  terms of the GNU Lesser General Public License as published by the Free
+ *  Software Foundation, either version 3 of the License, or (at your option)
+ *  any later version.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @author  Mike Gerwitz
+ * @package test
+ */
+
+var common    = require( './common' ),
+    assert    = require( 'assert' ),
+    builder   = common.require( 'class_builder' ),
+    fallback  = common.require( 'util' ).definePropertyFallback()
+;
+
+
+/**
+ * Methods declared as final should not be able to be overridden by subtypes.
+ * Simple as that.
+ */
+( function testFinalMethodsCannotBeOverridenBySubtypes()
+{
+    var Foo = builder.build(
+    {
+        'final public foo': function() {},
+    } );
+
+    try
+    {
+        // attempt to override (should fail)
+        builder.build( Foo,
+        {
+            'public foo': function() {},
+        } );
+    }
+    catch ( e )
+    {
+        assert.ok(
+            e.message.search( 'foo' ) !== -1,
+            "Final error message contains name of method"
+        );
+
+        return;
+    }
+
+    assert.fail( 'Should not be able to override final methods' );
+} )();
+