forummoderatoriteratorproxy.java

这是学习Java必须读懂两套源代码

/**
 * Copyright (C) 2001 Yasna.com. All rights reserved.
 *
 * ===================================================================
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by
 *        Yasna.com (http://www.Yasna.com)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Yazd" and "Yasna.com" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please
 *    contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Yazd",
 *    nor may "Yazd" appear in their name, without prior written
 *    permission of Yasna.com.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 YASNA.COM OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Yasna.com. For more information
 * on Yasna.com, please see <http://www.yasna.com>.
 */

package com.Yasna.forum;

import java.util.*;

/**
 * Protection proxy for Forum Moderator iterators. This is a special case
 * iterator proxy because users might not have read access to some of the 
 * forums that we need to proxy. The expected behavior is that only forums 
 * that users <b>do</b> have read access for will be returned. Therefore, 
 * we need to read in the results and only return an iterator for forums 
 * that the user can read.
 */
class ForumModeratorIteratorProxy extends IteratorProxy {

    private ArrayList forums = new ArrayList();

    public ForumModeratorIteratorProxy(Iterator iterator, Authorization
        authorization, ForumPermissions permissions)
    {
        //Dummy call to super-class. This specialized iterator proxy doesn't
        //use the superclass like the other iterators do.
        super(iterator, authorization, permissions);

        while (iterator.hasNext()) {
            Forum forum = (Forum)iterator.next();
            ForumPermissions forumPermissions = forum.getPermissions(authorization);
            //Create a new permissions object with the combination of the
            //permissions of this object and tempPermissions.
            //Check and see if the user has READ permissions. If not, throw an
            //an UnauthorizedException.
	    if (forumPermissions.get(ForumPermissions.SYSTEM_ADMIN)||
	    forumPermissions.get(ForumPermissions.FORUM_ADMIN)||
	    forumPermissions.get(ForumPermissions.MODERATOR)){
                ForumProxy proxy = new ForumProxy(forum, authorization, forumPermissions);
                forums.add(proxy);
	    }
        }

        this.iterator = forums.listIterator();
    }

    public Object next() throws java.util.NoSuchElementException {
        return iterator.next();
    }
}