| /******************************************************************************* |
| * Copyright (c) 2003, 2004 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| |
| package org.eclipse.osgi.framework.internal.core; |
| |
| import java.security.Permission; |
| import java.security.PermissionCollection; |
| import java.util.Enumeration; |
| import java.util.Hashtable; |
| |
| /** |
| * A simple Hashtable based collection of Permission objects. |
| * <p> |
| * The class' .implies method simply scans each permission |
| * individually and asks if the permission should be granted. |
| * No addition semantics is provided by the collection, so it is |
| * not possible to grant permissions whose "grantedness" is |
| * split across multiple stored Permissions. |
| * <p> |
| * Instances of this class can be used to store heterogeneous |
| * collections of permissions, as long as it is not necessary |
| * to remember when multiple occurances of .equal permissions |
| * are added. |
| * |
| */ |
| class PermissionsHash extends PermissionCollection { |
| private static final long serialVersionUID = 3258408426341284153L; |
| /** |
| * A hashtable to store the elements of the collection. |
| */ |
| Hashtable perms = new Hashtable(8); |
| |
| /** |
| * Constructs a new instance of this class. |
| * |
| */ |
| public PermissionsHash() { |
| super(); |
| } |
| |
| /** |
| * Adds the argument to the collection. |
| * |
| * @param perm java.security.Permission |
| * the permission to add to the collection. |
| * @exception IllegalStateException |
| * if the collection is read only. |
| */ |
| public void add(Permission perm) { |
| if (isReadOnly()) { |
| throw new SecurityException(); |
| } |
| |
| perms.put(perm, perm); |
| } |
| |
| /** |
| * Answers an enumeration of the permissions |
| * in the receiver. |
| * |
| * @return Enumeration |
| * the permissions in the receiver. |
| */ |
| public Enumeration elements() { |
| return perms.keys(); |
| } |
| |
| /** |
| * Indicates whether the argument permission is implied |
| * by the permissions contained in the receiver. |
| * |
| * @return boolean |
| * <code>true</code> if the argument permission |
| * is implied by the permissions in the receiver, |
| * and <code>false</code> if it is not. |
| * @param perm java.security.Permission |
| * the permission to check |
| */ |
| public boolean implies(Permission perm) { |
| Permission p = (Permission) perms.get(perm); |
| |
| if ((p != null) && p.implies(perm)) { |
| return true; |
| } |
| |
| Enumeration permsEnum = elements(); |
| |
| while (permsEnum.hasMoreElements()) { |
| if (((Permission) permsEnum.nextElement()).implies(perm)) { |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| } |