001    /* UnresolvedPermission.java -- Placeholder for unresolved permissions
002       Copyright (C) 1998, 2001, 2002, 2004, 2005  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package java.security;
040    
041    // All uses of Certificate in this file refer to the one in the listed
042    // package, not this one.
043    import java.security.cert.Certificate;
044    import java.util.Arrays;
045    import java.util.Enumeration;
046    import java.util.Hashtable;
047    import java.util.NoSuchElementException;
048    import java.util.Vector;
049    
050    /**
051     * This class is used to hold instances of all permissions that cannot
052     * be resolved to available permission classes when the security
053     * <code>Policy</code> object is instantiated.  This may happen when the
054     * necessary security class has not yet been downloaded from the network.
055     *
056     * <p>Instances of this class are re-resolved when
057     * <code>AccessController</code> check is done.  At that time, a scan is
058     * made of all existing <code>UnresolvedPermission</code> objects and they
059     * are converted to objects of the appropriate permission type if the class
060     * for that type is then available.
061     *
062     * @author Aaron M. Renn (arenn@urbanophile.com)
063     * @see Permission
064     * @see Permissions
065     * @see PermissionCollection
066     * @see Policy
067     * @since 1.1
068     * @status updated to 1.4
069     */
070    public final class UnresolvedPermission extends Permission
071    {
072      /**
073       * Compatible with JDK 1.1+.
074       */
075      private static final long serialVersionUID = -4821973115467008846L;
076    
077      /**
078       * The list of actions associated with this permission object.
079       *
080       * @serial the permission actions
081       */
082      private final String actions;
083    
084      /**
085       * The list of <code>Certificates</code> associated with this object.
086       */
087      private final transient Certificate[] certs;
088    
089      /**
090       * The name of the class this object should be resolved to.
091       *
092       * @serial the fully-qualified classname of the resolved type
093       */
094      // Package visible for use by UnresolvedPermissionCollection.
095      final String type;
096    
097      /**
098       * The name of the permission.
099       *
100       * @serial the permission name
101       */
102      private final String name;
103    
104      /**
105       * Create a new instance with all the information necessary to resolve it
106       * to an instance of the proper class at a future time.
107       *
108       * @param type the fully-qualified name of the class of this permission
109       * @param name the name of this permission
110       * @param actions the action list for this permission
111       * @param certs the list of certificates that sign this permission
112       */
113      public UnresolvedPermission(String type, String name, String actions,
114                                  Certificate[] certs)
115      {
116        super(name);
117        this.name = name;
118        this.type = type;
119        this.actions = actions;
120        this.certs = certs;
121      }
122    
123      /**
124       * This method returns <code>false</code> always to indicate that this
125       * permission does not imply the specified permission.  An
126       * <code>UnresolvedPermission</code> never grants any permissions.
127       *
128       * @param perm the <code>Permission</code> object to test
129       * @return false; until a permission is resolved, it implies nothing
130       */
131      public boolean implies(Permission perm)
132      {
133        return false;
134      }
135    
136      /**
137       * This method tests this permission for equality against the specified
138       * <code>Object</code>. This will be true if and only if the following
139       * conditions are met:<ul>
140       * <li>The specified <code>Object</code> is an UnresolvedPermission</li>
141       * <li>The specified permission has the same type (i.e., desired class name)
142       *     as this permission.</li>
143       * <li>The specified permission has the same name as this one.</li>
144       * <li>The specified permissoin has the same action list as this one.</li>
145       * <li>The specified permission has the same certificate list as this
146       *     one.</li>
147       * </ul>
148       *
149       * @param obj the <code>Object</code> to test for equality
150       * @return true if the specified object is equal to this one
151       */
152      public boolean equals(Object obj)
153      {
154        if (! (obj instanceof UnresolvedPermission))
155          return (false);
156        UnresolvedPermission up = (UnresolvedPermission) obj;
157        return up.name.equals(name) && up.actions.equals(actions)
158          && up.type.equals(type) && Arrays.equals(up.certs, certs);
159      }
160    
161      /**
162       * Returns a hash code value for this object. Following the lead of
163       * Permission, this returns the hashcode of the permission name.
164       *
165       * @return A hash value
166       */
167      public int hashCode()
168      {
169        return name.hashCode();
170      }
171    
172      /**
173       * This method returns the list of actions associated with this
174       * permission.
175       *
176       * @return the action list
177       */
178      public String getActions()
179      {
180        return actions;
181      }
182    
183      /**
184       * This method returns a <code>String</code> representation of this
185       * class.  The format is: '(unresolved "ClassName "name" "actions")'
186       *
187       * @return  <code>String</code> representation of this object
188       */
189      public String toString()
190      {
191        return "(unresolved " + type + ' ' + name + ' ' + actions + ')';
192      }
193    
194      /**
195       * This class returns a <code>PermissionCollection</code> object that can
196       * be used to store instances of <code>UnresolvedPermission</code>.
197       *
198       * @return a new <code>PermissionCollection</code>
199       */
200      public PermissionCollection newPermissionCollection()
201      {
202        return new UnresolvedPermissionCollection();
203      }
204    
205      /**
206       * Return the name of the class of the unresolved permission.
207       * @since 1.5
208       */
209      public String getUnresolvedType()
210      {
211        return type;
212      }
213    
214      /**
215       * Return the name of the unresolved permission.
216       * @since 1.5
217       */
218      public String getUnresolvedName()
219      {
220        return name;
221      }
222    
223      /**
224       * Return the actions of the unresolved permission, or null
225       * if there are no actions.
226       * @since 1.5
227       */
228      public String getUnresolvedActions()
229      {
230        return actions;
231      }
232    
233      /**
234       * Return the certificates of the unresolved permission.
235       * If there are no certificates, null is returned.  Otherwise,
236       * a new array is returned.
237       * @since 1.5
238       */
239      public Certificate[] getUnresolvedCerts()
240      {
241        if (certs == null)
242          return null;
243        return (Certificate[]) certs.clone();
244      }
245    } // class UnresolvedPermission
246    
247    /**
248     * Implements the permission collection for unresolved permissions, and
249     * obeys serialization of JDK.
250     *
251     * @author Eric Blake (ebb9@email.byu.edu)
252     */
253    class UnresolvedPermissionCollection extends PermissionCollection
254    {
255      /**
256       * Compatible with JDK 1.1+.
257       */
258      private static final long serialVersionUID = -7176153071733132400L;
259    
260      // Package-private to avoid a trampoline.
261      /**
262       * Hashtable where we store permissions.
263       *
264       * @serial map of typename to a Vector of permissions (you'd think Sun
265       *         would document this better!)
266       */
267      final Hashtable permissions = new Hashtable();
268    
269      /**
270       * Add a permission.
271       *
272       * @param perm the permission to add
273       * @throws IllegalArgumentException if perm is not an UnresolvedPermission
274       * @throws SecurityException if the collection is read-only
275       */
276      public void add(Permission perm)
277      {
278        if (isReadOnly())
279          throw new SecurityException();
280        if (! (perm instanceof UnresolvedPermission))
281          throw new IllegalArgumentException();
282        UnresolvedPermission up = (UnresolvedPermission) perm;
283        Vector v = (Vector) permissions.get(up.type);
284        if (v == null)
285          {
286            v = new Vector();
287            permissions.put(up.type, v);
288          }
289        v.add(up);
290      }
291    
292      /**
293       * Returns true if perm is implied by the collection.
294       *
295       * @param perm the permission to check
296       * @return false; unresolved permissions imply nothing
297       */
298      public boolean implies(Permission perm)
299      {
300        return false;
301      }
302    
303      /**
304       * Return the elements.
305       *
306       * @return the elements
307       */
308      public Enumeration elements()
309      {
310        return new Enumeration()
311        {
312          Enumeration main_enum = permissions.elements();
313          Enumeration sub_enum;
314    
315          public boolean hasMoreElements()
316          {
317            if (sub_enum == null)
318              {
319                if (main_enum == null)
320                  return false;
321                if (! main_enum.hasMoreElements())
322                  {
323                    main_enum = null;
324                    return false;
325                  }
326                Vector v = (Vector) main_enum.nextElement();
327                sub_enum = v.elements();
328              }
329            if (! sub_enum.hasMoreElements())
330              {
331                sub_enum = null;
332                return hasMoreElements();
333              }
334            return true;
335          }
336    
337          public Object nextElement()
338          {
339            if (! hasMoreElements())
340              throw new NoSuchElementException();
341            return sub_enum.nextElement();
342          }
343        };
344      }
345    } // class UnresolvedPermissionCollection