
/*
 * @(#)OrderedDenyOverridesRuleAlg.java
 *
 * Copyright 2003-2004 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistribution of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 * 
 *   2. Redistribution 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 Sun Microsystems, Inc. or the names of contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
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 */

package com.sun.xacml.combine;

import java.net.URI;
import java.net.URISyntaxException;


/**
 * This is the standard Ordered Deny Overrides rule combining algorithm. It
 * allows a single evaluation of Deny to take precedence over any number
 * of permit, not applicable or indeterminate results. Note that this uses
 * the regular Deny Overrides implementation since it is also orderd.
 *
 * @since 1.1
 * @author seth proctor
 */
public class OrderedDenyOverridesRuleAlg extends DenyOverridesRuleAlg
{

    /**
     * The standard URN used to identify this algorithm
     */
    public static final String algId =
        "urn:oasis:names:tc:xacml:1.0:rule-combining-algorithm:" +
        "ordered-deny-overrides";

    // a URI form of the identifier
    private static URI identifierURI;
    // exception if the URI was invalid, which should never be a problem
    private static RuntimeException earlyException;

    static {
        try {
            identifierURI = new URI(algId);
        } catch (URISyntaxException se) {
            earlyException = new IllegalArgumentException();
            earlyException.initCause(se);
        }
    }

    /**
     * Standard constructor.
     */
    public OrderedDenyOverridesRuleAlg() {
        super(identifierURI);

        if (earlyException != null)
            throw earlyException;
    }

}
