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1: /* AccessControlContext.java --- Access Control Context Class 2: Copyright (C) 1999, 2004 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: package java.security; 39: 40: import java.util.HashSet; 41: 42: /** 43: * AccessControlContext makes system resource access decsion 44: * based on permission rights. 45: * 46: * It is used for a specific context and has only one method 47: * checkPermission. It is similar to AccessController except 48: * that it makes decsions based on the current context instead 49: * of the the current thread. 50: * 51: * It is created by call AccessController.getContext method. 52: * 53: * @author Mark Benvenuto 54: * @since 1.2 55: */ 56: public final class AccessControlContext 57: { 58: private final ProtectionDomain[] protectionDomains; 59: private final DomainCombiner combiner; 60: 61: /** 62: * Construct a new AccessControlContext with the specified 63: * ProtectionDomains. <code>context</code> must not be 64: * null and duplicates will be removed. 65: * 66: * @param context The ProtectionDomains to use 67: */ 68: public AccessControlContext(ProtectionDomain[] context) 69: { 70: HashSet domains = new HashSet (context.length); 71: for (int i = 0; i < context.length; i++) 72: domains.add (context[i]); 73: protectionDomains = (ProtectionDomain[]) 74: domains.toArray (new ProtectionDomain[domains.size()]); 75: combiner = null; 76: } 77: 78: /** 79: * Construct a new AccessControlContext with the specified 80: * ProtectionDomains and DomainCombiner 81: * 82: * @since 1.3 83: */ 84: public AccessControlContext(AccessControlContext acc, 85: DomainCombiner combiner) 86: { 87: // XXX check permission to call this. 88: AccessControlContext acc2 = AccessController.getContext(); 89: protectionDomains = combiner.combine (acc2.protectionDomains, 90: acc.protectionDomains); 91: this.combiner = combiner; 92: } 93: 94: AccessControlContext (ProtectionDomain[] domains, AccessControlContext acc, 95: DomainCombiner combiner) 96: { 97: protectionDomains = combiner.combine (domains, acc.protectionDomains); 98: this.combiner = combiner; 99: } 100: 101: /** 102: * Returns the Domain Combiner associated with the AccessControlContext 103: * 104: * @return the DomainCombiner 105: */ 106: public DomainCombiner getDomainCombiner() 107: { 108: return combiner; 109: } 110: 111: /** 112: * Determines whether or not the specific permission is granted 113: * depending on the context it is within. 114: * 115: * @param perm a permission to check 116: * 117: * @throws AccessControlException if the permssion is not permitted 118: */ 119: public void checkPermission(Permission perm) throws AccessControlException 120: { 121: if (protectionDomains.length == 0) 122: throw new AccessControlException ("permission not granted"); 123: for (int i = 0; i < protectionDomains.length; i++) 124: if (!protectionDomains[i].implies(perm)) 125: throw new AccessControlException ("permission not granted"); 126: } 127: 128: /** 129: * Checks if two AccessControlContexts are equal. 130: * 131: * It first checks if obj is an AccessControlContext class, and 132: * then checks if each ProtectionDomain matches. 133: * 134: * @param obj The object to compare this class to 135: * 136: * @return true if equal, false otherwise 137: */ 138: public boolean equals(Object obj) 139: { 140: if (obj instanceof AccessControlContext) 141: { 142: AccessControlContext acc = (AccessControlContext) obj; 143: 144: if (acc.protectionDomains.length != protectionDomains.length) 145: return false; 146: 147: int i, j; 148: for (i = 0; i < protectionDomains.length; i++) 149: { 150: for (j = 0; j < acc.protectionDomains.length; j++) 151: { 152: if (acc.protectionDomains[j].equals (protectionDomains[i])) 153: break; 154: } 155: if (j == acc.protectionDomains.length) 156: return false; 157: } 158: return true; 159: } 160: return false; 161: } 162: 163: /** 164: * Computes a hash code of this class 165: * 166: * @return a hash code representing this class 167: */ 168: public int hashCode() 169: { 170: int h = 0; 171: for (int i = 0; i < protectionDomains.length; i++) 172: h ^= protectionDomains[i].hashCode(); 173: 174: return h; 175: } 176: }
GNU Classpath (0.17) |