| /* PermissionCollection.java -- A collection of permission objects |
| Copyright (C) 1998 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| As a special exception, if you link this library with other files to |
| produce an executable, this library does not by itself cause the |
| resulting executable to be covered by the GNU General Public License. |
| This exception does not however invalidate any other reasons why the |
| executable file might be covered by the GNU General Public License. */ |
| |
| |
| package java.security; |
| |
| import java.io.Serializable; |
| import java.util.Enumeration; |
| |
| /** |
| * This class models a group of Java permissions. It has convenient |
| * methods for determining whether or not a given permission is implied |
| * by any of the permissions in this collection. |
| * <p> |
| * Some care must be taken in storing permissions. First, a collection of |
| * the appropriate type must be created. This is done by calling the |
| * <code>newPermissionCollection</code> method on an object of the |
| * permission class you wish to add to the collection. If this method |
| * returns <code>null</code>, any type of <code>PermissionCollection</code> |
| * can be used to store permissions of that type. However, if a |
| * <code>PermissionCollection</code> collection object is returned, that |
| * type must be used. |
| * <p> |
| * The <code>PermissionCollection</code>'s returned |
| * by the <code>newPermissionCollection</code> instance in a subclass of |
| * <code>Permission</code> is a homogeneous collection. It only will |
| * hold permissions of one specified type - instances of the class that |
| * created it. Not all <code>PermissionCollection</code> subclasses |
| * have to hold permissions of only one type however. For example, |
| * the <code>Permissions</code> class holds permissions of many types. |
| * <p> |
| * Since the <code>newPermissionCollection</code> in <code>Permission</code> |
| * itself returns <code>null</code>, by default a permission can be stored |
| * in any type of collection unless it overrides that method to create its |
| * own collection type. |
| * |
| * @version 0.0 |
| * |
| * @author Aaron M. Renn (arenn@urbanophile.com) |
| */ |
| public abstract class PermissionCollection extends Object implements Serializable |
| { |
| |
| /*************************************************************************/ |
| |
| /* |
| * Class Variables |
| */ |
| |
| public static final String linesep = null; |
| |
| static |
| { |
| String linesep = System.getProperty("line.separator"); |
| if (linesep == null); |
| linesep = "\n"; |
| } |
| |
| /*************************************************************************/ |
| |
| /* |
| * Instance Variables |
| */ |
| |
| /** |
| * Indicates whether or not this collection is read only. |
| */ |
| private boolean readOnly; |
| |
| /*************************************************************************/ |
| |
| /* |
| * Constructors |
| */ |
| |
| /** |
| * This method initializes a new instance of <code>PermissionCollection</code>. |
| * This is provided only as a default constructor and does nothing in this |
| * class. |
| */ |
| public |
| PermissionCollection() |
| { |
| ; |
| } |
| |
| /*************************************************************************/ |
| |
| /* |
| * Instance Methods |
| */ |
| |
| /** |
| * This method tests whether or not this <code>PermissionCollection</code> |
| * object is read only. |
| * |
| * @return <code>true</code> if this collection is read only, <code>false</code> otherwise |
| */ |
| public boolean |
| isReadOnly() |
| { |
| return(readOnly); |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * This method sets this <code>PermissionCollection</code> object to be |
| * read only. No further permissions can be added to it after calling this |
| * method. |
| */ |
| public void |
| setReadOnly() |
| { |
| readOnly = true; |
| } |
| |
| /*************************************************************************/ |
| |
| /** |
| * This method adds a new <code>Permission</code> object to the collection. |
| * |
| * @param perm The <code>Permission</code> to add. |
| * |
| * @exception SecurityException If the collection is marked read only. |
| * @exception IllegalArgumentException If a permission of the specified type cannot be added |
| */ |
| public abstract void |
| add(Permission perm) throws SecurityException, IllegalArgumentException; |
| |
| /*************************************************************************/ |
| |
| /** |
| * This method returns an <code>Enumeration</code> of all the objects in |
| * this collection. |
| * |
| * @return An <code>Enumeration</code> of this collection's objects. |
| */ |
| public abstract Enumeration |
| elements(); |
| |
| /*************************************************************************/ |
| |
| /** |
| * This method tests whether the specified <code>Permission</code> object is |
| * implied by this collection of <code>Permission</code> objects. |
| * |
| * @param perm The <code>Permission</code> object to test. |
| * |
| * @return <code>true</code> if the specified <code>Permission</code> is implied by this collection, <code>false</code> otherwise. |
| */ |
| public abstract boolean |
| implies(Permission perm); |
| |
| /*************************************************************************/ |
| |
| /** |
| * This method returns a <code>String</code> representation of this |
| * collection. It will print the class name and has code in the same |
| * manner as <code>Object.toString()</code> then print a listing of all |
| * the <code>Permission</code> objects contained. |
| * |
| * @return A <code>String</code> representing this object. |
| */ |
| public String |
| toString() |
| { |
| StringBuffer sb = new StringBuffer(""); |
| |
| sb.append(super.toString() + " (" + linesep); |
| Enumeration e = elements(); |
| while (e.hasMoreElements()) |
| { |
| Object obj = e.nextElement(); |
| if (obj instanceof Permission) |
| sb.append(((Permission)obj).toString() + linesep); |
| } |
| |
| sb.append(")" + linesep); |
| return(sb.toString()); |
| } |
| |
| } // class PermissionCollection |
| |