ProsePermission.java :  » Byte-Code » PROSE » ch » ethz » prose » Java Open Source

// 
//  This file is part of the prose package.
// 
//  The contents of this file are subject to the Mozilla Public License
//  Version 1.1 (the "License"); you may not use this file except in
//  compliance with the License. You may obtain a copy of the License at
//  http://www.mozilla.org/MPL/
// 
//  Software distributed under the License is distributed on an "AS IS" basis,
//  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
//  for the specific language governing rights and limitations under the
//  License.
// 
//  The Original Code is prose.
// 
//  The Initial Developer of the Original Code is Andrei Popovici. Portions
//  created by Andrei Popovici are Copyright (C) 2002 Andrei Popovici.
//  All Rights Reserved.
// 
//  Contributor(s):
// $Id: ProsePermission.java,v 1.1.1.1 2003/07/02 15:30:50 apopovic Exp $
// =====================================================================
//
// (history at end)
//

package ch.ethz.prose;

// used packages
import java.io.Serializable;
import java.security.Permission;

/**
 * The class ProsePermission is used for access control of critical parts
 * in the RUNES system. The names recognized and their semantics can be
 * seen in the following list, to specify all names, one can use the wildcard "*".<p>
 *
 * <ul>
 * <li> registerListener: guards the creation of breakpoints
 * <li> startupExtensionSystem: if granted, <code>ProseSystem.startup</code>
 *      will be performed privileged under the the restrictions of <code>ProseSystem</code>
 *      only. This permission should simplify the Java security policy definition, as
 *      only <code>ProseSystem</code> needs several fine grained permissions, and all
 *      classes that need to start runes can do with the ProsePermission "startupExtensionSystem"
 * </ul>
 * <p>
 * So an entry in the standard policy file allowing all classes to install
 * extensions would look like:<p><pre>
 * grant {
 *   ch.ethz.prose.ProsePermission "registerListener";
 * }
 * </pre>
 *
 * @version  $Revision: 1.1.1.1 $
 * @author  Marcel Muller
 */
public final class ProsePermission extends Permission implements Serializable {

  private static final long serialVersionUID = 3258134652291133489L;  
  private final static String[] NAMES = {"registerListener", "startupExtensionSystem"};
    private final static String WILDCARD = "*";

    private int nameIndex = -1;

    /**
     * Constructs a runes permission with the specified name.
     *
     * @param name the name of the permission or <code>*</code> for all names.
     */
    public ProsePermission(String name) {
  super(name);

  if (name == null) {
      throw new NullPointerException("name can't be null");
  }

  for (int i=0; i<NAMES.length; i++) {
      if (name.equals(NAMES[i])) {
    nameIndex = i;
    break;
      }
  }

  if (nameIndex == -1) {
      String names = NAMES[0];
      for (int i=1; i<NAMES.length; i++) {
    names += ", " + NAMES[i];
      }

      throw new IllegalArgumentException("Invalid name \""+name+"\". Valid choices are: " + names);
  }
    }

    /**
     * Constructs a runes permission with the specified name and action. This constructor
     * seems to be necessary to the standard policy file implementation though this
     * class completely ignores the action parameter.
     *
     * @param name the name of the permission or <code>*</code> for all names.
     * @param actions ignored!!!
     */
    public ProsePermission(String name, String actions) {
  this(name);
    }

    /**
     * Checks whether this permission implies permission <code>p</code> (if names are
     * equal or at least this permission was created with the wildcard as parameter) or not.
     *
     * @param p the permission to be compared to
     */
    public boolean implies(Permission p) {
  if (p instanceof ProsePermission) {
      if (getName().equals(WILDCARD)) {
    return true;
      }

      return nameIndex == ((ProsePermission) p).nameIndex;
  }

  return false;
    }

    /**
     * Returns an empty string as this class does not use actions.
     */
    public String getActions() {
  return "";
    }

    public boolean equals(Object obj) {
  if (obj instanceof ProsePermission) {
      return nameIndex == ((ProsePermission) obj).nameIndex;
  } else {
      return false;
  }
    }

    public int hashCode() {
  return getName().hashCode();
    }
}


//======================================================================
//
// $Log: ProsePermission.java,v $
// Revision 1.1.1.1  2003/07/02 15:30:50  apopovic
// Imported from ETH Zurich
//
// Revision 1.1  2003/05/05 13:58:29  popovici
// renaming from runes to prose
//
// Revision 1.4  2003/03/04 18:36:37  popovici
// Organization of imprts
//
// Revision 1.3  2003/03/04 11:27:16  popovici
// Important refactorization step (march):
// - removal of 'JoinPointEvents'; JoinPoints now have the same function as events
// - reimplementation of the JVMAIDebuggerAspectInterface (better performance, coding conventions, removal of ProseVM
//   structures
//
// Revision 1.2  2002/03/28 13:48:37  popovici
// Mozilla-ified
//
// Revision 1.1.1.1  2001/11/29 18:13:16  popovici
// Sources from runes
//
// Revision 1.1.2.3  2001/04/04 13:08:52  mrmuller
// JavaDoc improved
//
// Revision 1.1.2.2  2001/03/16 17:29:15  mrmuller
// cosmetics, javadoc and exception handling changes
//
// Revision 1.1.2.1  2001/03/16 13:12:29  mrmuller
// initial release of new (really) secure extension insertion mechanism
//
//