BEGIN LICENSE BLOCK *****
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The contents of this file are subject to the Eclipse Public
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except in compliance with the License. You may obtain a copy of
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Software distributed under the License is distributed on an "AS
IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
implied. See the License for the specific language governing
rights and limitations under the License.
Copyright (C) 2002-2004 Jan Arne Petersen 
Copyright (C) 2004-2005 Thomas E Enebo 
Alternatively, the contents of this file may be used under the terms of
either of the GNU General Public License Version 2 or later (the "GPL"),
or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
in which case the provisions of the GPL or the LGPL are applicable instead
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END LICENSE BLOCK /***** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * License Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2002-2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
 * Copyright (C) 2004-2005 Thomas E Enebo <enebo@acm.org>
 * 
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the EPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
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package org.jruby.internal.runtime.methods;

import org.jruby.RubyModule;
import org.jruby.runtime.Block;
import org.jruby.runtime.CallType;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.Visibility;
import org.jruby.runtime.builtin.IRubyObject;

This class represents a singleton type of method used as a marker for
missing or "undef'ed" methods. Only one instance is ever created, and it
can't be invoked.
/**
 * This class represents a singleton type of method used as a marker for
 * missing or "undef'ed" methods. Only one instance is ever created, and it
 * can't be invoked.
 */
public final class UndefinedMethod extends DynamicMethod {

    public static final UndefinedMethod INSTANCE = new UndefinedMethod();

    
Constructor for the one UndefinedMethod instance.
/**
     * Constructor for the one UndefinedMethod instance.
     */
    private UndefinedMethod() {
        super("(undefined)");
    }

    
The one implementation of call, which throws an exception because
UndefinedMethod can't be invoked.
Throws:
UnsupportedOperationException – 
See Also:
DynamicMethod.call(ThreadContext, IRubyObject, RubyModule, String)/**
     * The one implementation of call, which throws an exception because
     * UndefinedMethod can't be invoked.
     *
     * @throws UnsupportedOperationException
     * @see DynamicMethod#call(ThreadContext, IRubyObject, RubyModule, String)
     */
    public IRubyObject call(ThreadContext context, IRubyObject self, RubyModule klazz, String name, IRubyObject[] args, Block block) {
        throw new UnsupportedOperationException("BUG: invoking UndefinedMethod.call; report at http://bugs.jruby.org");
    }
    
    
A dummy implementation of dup that just returns the singleton instance.
Returns:
The singleton instance/**
     * A dummy implementation of dup that just returns the singleton instance.
     * 
     * @return The singleton instance
     */
    public DynamicMethod dup() {
        return INSTANCE;
    }

    
Retrieve the singleton instance.
Returns:
The singleton instance/**
     * Retrieve the singleton instance.
     * 
     * @return The singleton instance
     */
    public static UndefinedMethod getInstance() {
        return INSTANCE;
    }

    
Dummy override of setImplementationClass that does nothing.
Params:
implClass – Ignored/**
     * Dummy override of setImplementationClass that does nothing.
     * 
     * @param implClass Ignored
     */
    @Override
    public void setImplementationClass(RubyModule implClass) {
        // UndefinedMethod should be immutable
    }

    @Override
    public void setDefinedClass(RubyModule definedClass) {
        // UndefinedMethod should be immutable
    }

    
Dummy implementation of setVisibility that does nothing.
Params:
visibility – Ignored/**
     * Dummy implementation of setVisibility that does nothing.
     * 
     * @param visibility Ignored
     */
    @Override
    public void setVisibility(Visibility visibility) {
        // UndefinedMethod should be immutable
    }

    @Override
    public void setIsBuiltin(boolean isBuiltin) {
        // UndefinedMethod should be immutable - isBuiltin() always returns false
    }

    @Override
    public void setNotImplemented(boolean setNotImplemented) {
        // UndefinedMethod should be immutable
    }

    
UndefinedMethod is always visible because it's only used as a marker for
missing or undef'ed methods.
Params:
caller – The calling object
callType – The type of call
Returns:
true always/**
     * UndefinedMethod is always visible because it's only used as a marker for
     * missing or undef'ed methods.
     * 
     * @param caller The calling object
     * @param callType The type of call
     * @return true always
     */
    @Override
    public boolean isCallableFrom(IRubyObject caller, CallType callType) {
        return true;
    }
}