/* ======================================================================
The Bodington System Software License, Version 1.0
  
Copyright (c) 2001 The University of Leeds.  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.  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 acknowledgement:  "This product includes
software developed by the University of Leeds
(http://www.bodington.org/)."  Alternately, this acknowledgement may
appear in the software itself, if and wherever such third-party
acknowledgements normally appear.

4.  The names "Bodington", "Nathan Bodington", "Bodington System",
"Bodington Open Source Project", and "The University of Leeds" must not be
used to endorse or promote products derived from this software without
prior written permission. For written permission, please contact
d.gardner@leeds.ac.uk.

5.  The name "Bodington" may not appear in the name of products derived
from this software without prior written permission of the University of
Leeds.

THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO,  TITLE,  THE IMPLIED WARRANTIES 
OF QUALITY  AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO 
EVENT SHALL THE UNIVERSITY OF LEEDS 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 was originally created by the University of Leeds and may contain voluntary 
contributions from others.  For more information on the Bodington Open Source Project, please 
see http://bodington.org/

====================================================================== */

package org.bodington.server.realm;

import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

/**
 * An instance of this class representsa type of action a user might
 * be allowed to carry out with a resource item.  A permission is
 * displayed as a verb.  This class is used by the ACL code.
 * 
 * @author Jon Maber
 * @version 1.0
 */
public class Permission implements java.security.acl.Permission
	{
	private String name;
	
	private static Hashtable permissions;
	private static Vector permissions_in_order;
	
	
	/**
	 * The "see" permission.
	 */
	public static final Permission SEE;
	/**
	 * The "view" permission.
	 */
	public static final Permission VIEW;
	/**
	 * The "edit" permission.  Etc......
	 */
	public static final Permission EDIT;
	public static final Permission RECORD;
	public static final Permission REVIEW;
	public static final Permission POST;
	public static final Permission MARK;
	public static final Permission CREATE;
	public static final Permission UPLOAD;
	public static final Permission MANAGE;
	public static final Permission ADMINISTER;
	public static final Permission SYSADMIN;
	
	static
		{
		permissions = new Hashtable();
		permissions_in_order = new Vector();
		permissions_in_order.addElement( SEE         = new Permission( "see" ) );
		permissions_in_order.addElement( VIEW        = new Permission( "view" ) );
		permissions_in_order.addElement( EDIT        = new Permission( "edit" ) );
		permissions_in_order.addElement( RECORD      = new Permission( "record" ) );
		permissions_in_order.addElement( REVIEW      = new Permission( "review" ) );
		permissions_in_order.addElement( POST        = new Permission( "post" ) );
		permissions_in_order.addElement( MARK        = new Permission( "mark" ) );
		permissions_in_order.addElement( CREATE      = new Permission( "create" ) );
		permissions_in_order.addElement( UPLOAD      = new Permission( "upload" ) );
		permissions_in_order.addElement( MANAGE      = new Permission( "manage" ) );
		permissions_in_order.addElement( ADMINISTER  = new Permission( "administer" ) );
		permissions_in_order.addElement( SYSADMIN    = new Permission( "sysadmin" ) );
		for ( int i=0; i<permissions_in_order.size(); i++ )
		    {
		    permissions.put( ((Permission)permissions_in_order.elementAt( i )).toString(), 
		                        permissions_in_order.elementAt( i ) );
            }
		}

	/**
	 * This static method attempts to find the permissions from the supplied name.
	 * @param name The action verb of the requested Permission.
	 * @return The permission requested.
	 */
	public static Permission forName( String name )
		{
		return (Permission)permissions.get( name );
		}
	
	/**
	 * This static method returns an enumeration of all possible
	 * permissions.  The order is in increasing "seriousness".
	 * 
	 * @return An Enumeration whose elements are of type Permission.
	 */
	public static Enumeration permissions()
		{
		return permissions_in_order.elements();
		}
		
	/**
	 * Constructs a new Permission with a given name.
	 * 
	 * @param name The action verb that this Persmission will represent.
	 */
	private Permission( String name )
		{
		this.name = name;
		}
		
    /**
     * String representation of this Permission.
     * 
     * @return Returns the action verb for the permission.
     */
    public String toString()
    	{
        return name;
	    }
	
    /**
     * Tests equality.
     * 
     * @param another The Persmission to test.
     * @return Returns true if the other Permission represents the same action
     * verb as this one.
     */
    public boolean equals(Object another)
	    {
        return another.toString().equals( name );
    	}

	}