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 * Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package com.sun.xml.internal.xsom.util;

import com.sun.xml.internal.xsom.XSType;

/**
 * A simple abstraction for a set of Types that defines containment functions.
 * 
 * @author <a href="mailto:Ryan.Shoemaker@Sun.COM">Ryan Shoemaker</a>, Sun Microsystems, Inc.
 */
public abstract class TypeSet {

    /**
     * Return true if this TypeSet contains the specified type.
     * 
     * Concrete implementations of this method determine what it
     * means for the TypeSet to "contain" a type.
     *  
     * @param type the type
     * @return true iff this TypeSet contains the specified type
     */
    public abstract boolean contains(XSType type);

    /**
     * Calculate the TypeSet formed by the intersection of two
     * other TypeSet objects.
     * 
     * @param a a TypeSet
     * @param b another TypeSet
     * @return the intersection of a and b
     */
    public static TypeSet intersection(final TypeSet a, final TypeSet b) {
        return new TypeSet(){
            public boolean contains(XSType type) {
                return a.contains(type) && b.contains(type);
            }
        };
    }

    /**
     * Calculate the TypeSet formed by the union of two
     * other TypeSet objects.
     * 
     * @param a a TypeSet
     * @param b another TypeSet
     * @return the union of a and b
     */
    public static TypeSet union(final TypeSet a, final TypeSet b) {
        return new TypeSet(){
            public boolean contains(XSType type) {
                return a.contains(type) || b.contains(type);
            }
        };
    }
}