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/*

 * Copyright (C) 2004-2011

 *

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 * of this software and associated documentation files (the "Software"), to deal

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 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

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 */

package com.sun.xml.internal.rngom.nc;

import com.sun.xml.internal.rngom.ast.om.ParsedNameClass;

import javax.xml.namespace.QName;

import java.io.Serializable;

import java.util.HashSet;

import java.util.Set;

/**

 * Name class is a set of {@link QName}s.

 */

public abstract class NameClass implements ParsedNameClass, Serializable {

    static final int SPECIFICITY_NONE = -1;

    static final int SPECIFICITY_ANY_NAME = 0;

    static final int SPECIFICITY_NS_NAME = 1;

    static final int SPECIFICITY_NAME = 2;

    /**

     * Returns true if the given {@link QName} is a valid name

     * for this QName.

     */

    public abstract boolean contains(QName name);

    public abstract int containsSpecificity(QName name);

    /**

     * Visitor pattern support.

     */

    public abstract <V> V accept(NameClassVisitor<V> visitor);

    /**

     * Returns true if the name class accepts infinite number of

     * {@link QName}s.

     *

     * <p>

     * Intuitively, this method returns true if the name class is

     * some sort of wildcard.

     */

    public abstract boolean isOpen();

    /**

     * If the name class is closed (IOW !{@link #isOpen()}),

     * return the set of names in this name class. Otherwise the behavior

     * is undefined.

     */

    public Set<QName> listNames() {

        final Set<QName> names = new HashSet<QName>();

        accept(new NameClassWalker() {

            @Override

            public Void visitName(QName name) {

                names.add(name);

                return null;

            }

        });

        return names;

    }

    /**

     * Returns true if the intersection between this name class

     * and the specified name class is non-empty.

     */

    public final boolean hasOverlapWith( NameClass nc2 ) {

        return OverlapDetector.overlap(this,nc2);

    }

    /** Sigleton instance that represents "anyName". */

    public static final NameClass ANY = new AnyNameClass();

    /**

     * Sigleton instance that accepts no name.

     *

     * <p>

     * This instance is useful when doing boolean arithmetic over

     * name classes (such as computing an inverse of a given name class, etc),

     * even though it can never appear in a RELAX NG surface syntax.

     *

     * <p>

     * Internally, this instance is also used for:

     * <ol>

     *  <li>Used to recover from errors during parsing.

     *  <li>Mark element patterns with &lt;notAllowed/> content model.

     * </ol>

     */

    public static final NameClass NULL = new NullNameClass();

}