1/* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18package java.security; 19 20import java.io.IOException; 21import java.io.ObjectInputStream; 22import java.io.ObjectOutputStream; 23import java.io.ObjectStreamField; 24import java.util.Enumeration; 25import java.util.NoSuchElementException; 26 27import org.apache.harmony.security.internal.nls.Messages; 28 29/** 30 * Specific {@code PermissionCollection} for storing {@code AllPermission}s. All 31 * instances of {@code AllPermission} are equivalent, so it is enough to store a 32 * single added instance. 33 * 34 * @see AllPermission 35 */ 36final class AllPermissionCollection extends PermissionCollection { 37 38 private static final long serialVersionUID = -4023755556366636806L; 39 40 private static final ObjectStreamField[] serialPersistentFields = { new ObjectStreamField( 41 "all_allowed", Boolean.TYPE), }; //$NON-NLS-1$ 42 43 // Single element of collection. 44 private transient Permission all; 45 46 /** 47 * Adds an {@code AllPermission} to the collection. 48 */ 49 @Override 50 public void add(Permission permission) { 51 if (isReadOnly()) { 52 throw new SecurityException(Messages.getString("security.15")); //$NON-NLS-1$ 53 } 54 if (!(permission instanceof AllPermission)) { 55 throw new IllegalArgumentException(Messages.getString("security.16", //$NON-NLS-1$ 56 permission)); 57 } 58 all = permission; 59 } 60 61 /** 62 * Returns the enumeration of the collection. 63 */ 64 @Override 65 public Enumeration<Permission> elements() { 66 return new SingletonEnumeration<Permission>(all); 67 } 68 69 /** 70 * An auxiliary implementation for enumerating a single object. 71 * 72 */ 73 final static class SingletonEnumeration<E> implements Enumeration<E> { 74 75 private E element; 76 77 /** 78 * Constructor taking the single element. 79 * @param single the element 80 */ 81 public SingletonEnumeration(E single) { 82 element = single; 83 } 84 85 /** 86 * Returns true if the element is not enumerated yet. 87 */ 88 public boolean hasMoreElements() { 89 return element != null; 90 } 91 92 /** 93 * Returns the element and clears internal reference to it. 94 */ 95 public E nextElement() { 96 if (element == null) { 97 throw new NoSuchElementException(Messages.getString("security.17")); //$NON-NLS-1$ 98 } 99 E last = element; 100 element = null; 101 return last; 102 } 103 } 104 105 /** 106 * Indicates whether the argument permission is implied by the receiver. 107 * {@code AllPermission} objects imply all other permissions. 108 * 109 * @return boolean {@code true} if the argument permission is implied by the 110 * receiver, and {@code false} if it is not. 111 * @param permission 112 * the permission to check. 113 */ 114 @Override 115 public boolean implies(Permission permission) { 116 return all != null; 117 } 118 119 /** 120 * Writes the fields according to expected format, adding the boolean field 121 * {@code all_allowed} which is {@code true} if this collection is not 122 * empty. 123 */ 124 private void writeObject(java.io.ObjectOutputStream out) throws IOException { 125 ObjectOutputStream.PutField fields = out.putFields(); 126 fields.put("all_allowed", all != null); //$NON-NLS-1$ 127 out.writeFields(); 128 } 129 130 /** 131 * Restores internal state. 132 */ 133 private void readObject(java.io.ObjectInputStream in) throws IOException, 134 ClassNotFoundException { 135 ObjectInputStream.GetField fields = in.readFields(); 136 if (fields.get("all_allowed", false)) { //$NON-NLS-1$ 137 all = new AllPermission(); 138 } 139 } 140} 141