/*
 * @(#)X500NameAttribute.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
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
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 *
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 */

package com.sun.xacml.attr;

import java.net.URI;

import javax.security.auth.x500.X500Principal;

import org.w3c.dom.Node;


/**
 * Representation of an X500 Name.
 *
 * @since 1.0
 * @author Marco Barreno
 * @author Seth Proctor
 */
public class X500NameAttribute extends AttributeValue
{
   
    /**
     * Official name of this type
     */
    public static final String identifier =
        "urn:oasis:names:tc:xacml:1.0:data-type:x500Name";
 
    // the actual value being stored
    private X500Principal value;

    /**
     * URI version of name for this type
     * <p>
     * This field is initialized by a static initializer so that
     * we can catch any exceptions thrown by URI(String) and
     * transform them into a RuntimeException, since this should
     * never happen but should be reported properly if it ever does.
     */
    private static URI identifierURI;

    /**
     * RuntimeException that wraps an Exception thrown during the
     * creation of identifierURI, null if none.
     */
    private static RuntimeException earlyException;

    /**
     * Static initializer that initializes the identifierURI
     * class field so that we can catch any exceptions thrown
     * by URI(String) and transform them into a RuntimeException.
     * Such exceptions should never happen but should be reported
     * properly if they ever do.
     */
    static {
        try {
            identifierURI = new URI(identifier);
        } catch (Exception e) {
            earlyException = new IllegalArgumentException();
            earlyException.initCause(e);
        }
    };

    /**
     * Creates a new <code>X500NameAttribute</code> that represents the
     * value supplied.
     *
     * @param value the X500 Name to be represented
     */
    public X500NameAttribute(X500Principal value) {
        super(identifierURI);
        
        if (earlyException != null)
            throw earlyException;

        this.value = value;
    }

    /**
     * Returns a new <codeX500NameAttribute</code> that represents
     * the X500 Name at a particular DOM node.
     *
     * @param root the <code>Node</code> that contains the desired value
     * @return a new <code>X500NameAttribute</code> representing the
     *         appropriate value
     * @throws IllegalArgumentException if value is improperly specified
     */
    public static X500NameAttribute getInstance(Node root) 
        throws IllegalArgumentException
    {
        return getInstance(root.getFirstChild().getNodeValue());
    }

    /**
     * Returns a new <code>X500NameAttribute</code> that represents
     * the X500 Name value indicated by the string provided.
     *
     * @param value a string representing the desired value
     * @return a new <code>X500NameAttribute</code> representing the
     *         appropriate value
     * @throws IllegalArgumentException if value is improperly specified
     */
    public static X500NameAttribute getInstance(String value)
        throws IllegalArgumentException
    {
        return new X500NameAttribute(new X500Principal(value));
    }

    /**
     * Returns the name value represented by this object
     *
     * @return the name
     */
    public X500Principal getValue() {
        return value;
    }

    /**
     * Returns true if the input is an instance of this class and if its
     * value equals the value contained in this class. This method 
     * deviates slightly from the XACML spec in the way that it handles
     * RDNs with multiple attributeTypeAndValue pairs and some
     * additional canonicalization steps. This method uses
     * the procedure used by 
     * <code>javax.security.auth.x500.X500Principal.equals()</code>, while the
     * XACML spec uses a slightly different procedure. In practice, it is
     * expected that this difference will not be noticeable. For more
     * details, refer to the javadoc for <code>X500Principal.equals()</code> 
     * and the XACML specification.
     *
     * @param o the object to compare
     *
     * @return true if this object and the input represent the same value
     */
    public boolean equals(Object o) {
        if (! (o instanceof X500NameAttribute))
            return false;

        X500NameAttribute other = (X500NameAttribute)o;

        return value.equals(other.value);
    }

    /**
     * Returns the hashcode value used to index and compare this object with
     * others of the same type. Typically this is the hashcode of the backing
     * data object.
     *
     * @return the object's hashcode value
     */
    public int hashCode() {
        return value.hashCode();
    }

    /**
     *
     */
    public String encode() {
        return value.getName();
    }

}