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2  * Version: CPL 1.0/GPL 2.0/LGPL 2.1
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5  * License Version 1.0 (the "License"); you may not use this file
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14  * Copyright (C) 2002-2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
15  * Copyright (C) 2004-2006 Thomas E Enebo <enebo@acm.org>
16  * Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de>
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30 package org.jruby;
31
32 import org.jruby.runtime.ClassIndex;
33 import org.jruby.runtime.ObjectAllocator;
34 import org.jruby.runtime.builtin.IRubyObject;
35 import org.jruby.util.collections.SinglyLinkedList;
36
37 public class MetaClass extends RubyClass {
38
39     public MetaClass(Ruby runtime, RubyClass superClass, ObjectAllocator allocator, SinglyLinkedList parentCRef) {
40         super(runtime, runtime.getClass("Class"), superClass, allocator, parentCRef, null);
41         
42         this.index = ClassIndex.CLASS;
43     }
44  
45     public boolean isSingleton() {
46         return true;
47     }
48
49     protected RubyClass subclass() {
50         throw getRuntime().newTypeError("can't make subclass of virtual class");
51     }
52
53     /**
54      * If an object uses an anonymous class 'class << obj', then this grabs the original
55      * metaclass and not the one that get injected as a result of 'class << obj'.
56      */
57     public RubyClass getRealClass() {
58         return getSuperClass().getRealClass();
59     }
60     
61     public void methodAdded(RubySymbol symbol) {
62         getAttachedObject().callMethod(getRuntime().getCurrentContext(), "singleton_method_added", symbol);
63     }
64
65     public IRubyObject getAttachedObject() {
66         // Though it may not be obvious, attachToObject is always called just after instance
67 // creation. Kind of a brittle arrangement here...
68 return getInstanceVariable("__attached__");
69     }
70
71     public IRubyObject allocateObject() {
72         throw getRuntime().newTypeError("can't create instance of virtual class");
73     }
74 }
75
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