J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999-2006 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package java.security; |
| 27 | |
| 28 | /** |
| 29 | * A <code>DomainCombiner</code> provides a means to dynamically |
| 30 | * update the ProtectionDomains associated with the current |
| 31 | * <code>AccessControlContext</code>. |
| 32 | * |
| 33 | * <p> A <code>DomainCombiner</code> is passed as a parameter to the |
| 34 | * appropriate constructor for <code>AccessControlContext</code>. |
| 35 | * The newly constructed context is then passed to the |
| 36 | * <code>AccessController.doPrivileged(..., context)</code> method |
| 37 | * to bind the provided context (and associated <code>DomainCombiner</code>) |
| 38 | * with the current execution Thread. Subsequent calls to |
| 39 | * <code>AccessController.getContext</code> or |
| 40 | * <code>AccessController.checkPermission</code> |
| 41 | * cause the <code>DomainCombiner.combine</code> to get invoked. |
| 42 | * |
| 43 | * <p> The combine method takes two arguments. The first argument represents |
| 44 | * an array of ProtectionDomains from the current execution Thread, |
| 45 | * since the most recent call to <code>AccessController.doPrivileged</code>. |
| 46 | * If no call to doPrivileged was made, then the first argument will contain |
| 47 | * all the ProtectionDomains from the current execution Thread. |
| 48 | * The second argument represents an array of inherited ProtectionDomains, |
| 49 | * which may be <code>null</code>. ProtectionDomains may be inherited |
| 50 | * from a parent Thread, or from a privileged context. If no call to |
| 51 | * doPrivileged was made, then the second argument will contain the |
| 52 | * ProtectionDomains inherited from the parent Thread. If one or more calls |
| 53 | * to doPrivileged were made, and the most recent call was to |
| 54 | * doPrivileged(action, context), then the second argument will contain the |
| 55 | * ProtectionDomains from the privileged context. If the most recent call |
| 56 | * was to doPrivileged(action), then there is no privileged context, |
| 57 | * and the second argument will be <code>null</code>. |
| 58 | * |
| 59 | * <p> The <code>combine</code> method investigates the two input arrays |
| 60 | * of ProtectionDomains and returns a single array containing the updated |
| 61 | * ProtectionDomains. In the simplest case, the <code>combine</code> |
| 62 | * method merges the two stacks into one. In more complex cases, |
| 63 | * the <code>combine</code> method returns a modified |
| 64 | * stack of ProtectionDomains. The modification may have added new |
| 65 | * ProtectionDomains, removed certain ProtectionDomains, or simply |
| 66 | * updated existing ProtectionDomains. Re-ordering and other optimizations |
| 67 | * to the ProtectionDomains are also permitted. Typically the |
| 68 | * <code>combine</code> method bases its updates on the information |
| 69 | * encapsulated in the <code>DomainCombiner</code>. |
| 70 | * |
| 71 | * <p> After the <code>AccessController.getContext</code> method |
| 72 | * receives the combined stack of ProtectionDomains back from |
| 73 | * the <code>DomainCombiner</code>, it returns a new |
| 74 | * AccessControlContext that has both the combined ProtectionDomains |
| 75 | * as well as the <code>DomainCombiner</code>. |
| 76 | * |
| 77 | * @see AccessController |
| 78 | * @see AccessControlContext |
| 79 | * @since 1.3 |
| 80 | */ |
| 81 | public interface DomainCombiner { |
| 82 | |
| 83 | /** |
| 84 | * Modify or update the provided ProtectionDomains. |
| 85 | * ProtectionDomains may be added to or removed from the given |
| 86 | * ProtectionDomains. The ProtectionDomains may be re-ordered. |
| 87 | * Individual ProtectionDomains may be modified (with a new |
| 88 | * set of Permissions, for example). |
| 89 | * |
| 90 | * <p> |
| 91 | * |
| 92 | * @param currentDomains the ProtectionDomains associated with the |
| 93 | * current execution Thread, up to the most recent |
| 94 | * privileged <code>ProtectionDomain</code>. |
| 95 | * The ProtectionDomains are are listed in order of execution, |
| 96 | * with the most recently executing <code>ProtectionDomain</code> |
| 97 | * residing at the beginning of the array. This parameter may |
| 98 | * be <code>null</code> if the current execution Thread |
| 99 | * has no associated ProtectionDomains.<p> |
| 100 | * |
| 101 | * @param assignedDomains an array of inherited ProtectionDomains. |
| 102 | * ProtectionDomains may be inherited from a parent Thread, |
| 103 | * or from a privileged <code>AccessControlContext</code>. |
| 104 | * This parameter may be <code>null</code> |
| 105 | * if there are no inherited ProtectionDomains. |
| 106 | * |
| 107 | * @return a new array consisting of the updated ProtectionDomains, |
| 108 | * or <code>null</code>. |
| 109 | */ |
| 110 | ProtectionDomain[] combine(ProtectionDomain[] currentDomains, |
| 111 | ProtectionDomain[] assignedDomains); |
| 112 | } |