/*

 * Copyright (c) 1999, 2011, 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

/**

  * Supports checking an attribute set satisfies a filter

  * that is specified as a set of "matching" attributes.

  * Checking is done by determining whether the given attribute set

  * is a superset of the matching ones.

  *

  * @author Rosanna Lee

  */

package com.sun.jndi.toolkit.dir;

import javax.naming.*;

import javax.naming.directory.*;

public class ContainmentFilter implements AttrFilter {

    private Attributes matchingAttrs;

    public ContainmentFilter(Attributes match) {

        matchingAttrs = match;

    }

    public boolean check(Attributes attrs) throws NamingException {

        return matchingAttrs == null ||

            matchingAttrs.size() == 0 ||

            contains(attrs, matchingAttrs);

    }

    // returns true if superset contains subset

    public static boolean contains(Attributes superset, Attributes subset)

        throws NamingException {

          if (subset == null)

            return true;  // an empty set is always a subset

            NamingEnumeration<? extends Attribute> m = subset.getAll();

            while (m.hasMore()) {

                if (superset == null) {

                    return false;  // contains nothing

                }

                Attribute target = m.next();

                Attribute fromSuper = superset.get(target.getID());

                if (fromSuper == null) {

                    return false;

                } else {

                    // check whether attribute values match

                    if (target.size() > 0) {

                        NamingEnumeration<?> vals = target.getAll();

                        while (vals.hasMore()) {

                            if (!fromSuper.contains(vals.next())) {

                                return false;

                            }

                        }

                    }

                }

            }

            return true;

        }

}