/*
 * Copyright (c) 2001-2013 Oracle and/or its affiliates. All rights reserved.
 *
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 * modification, are permitted provided that the following conditions
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 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 */

package com.sun.msv.verifier.regexp;

import com.sun.msv.grammar.ElementExp;

/**
 * special Token that matchs any element.
 * 
 * this token is used only for error recovery, to compute
 * "residual of elements of concern"(EoCR).
 * 
 * EoCR is defined as follows
 * 
 * <PRE>
 * EoCR(exp) := exp/e1 | exp/e2 | ... | exp/en
 * 
 * {ei} = elements of concern
 * exp/ei = residual(exp,ei)
 * '|' represents choice
 * </PRE>
 * 
 * @author <a href="mailto:kohsuke.kawaguchi@eng.sun.com">Kohsuke KAWAGUCHI</a>
 */
public final class AnyElementToken extends ElementToken
{
    /**
     * use this singleton instance instead of creating an object.
     */
    public static final Token theInstance = new AnyElementToken();
    private AnyElementToken(){ super(null); }
    public boolean match( ElementExp exp ) { return true; }
}
