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