| /* |
| * $Header: /cvshome/build/org.osgi.service.condpermadmin/src/org/osgi/service/condpermadmin/Condition.java,v 1.13 2006/06/16 16:31:37 hargrave Exp $ |
| * |
| * Copyright (c) OSGi Alliance (2004, 2006). All Rights Reserved. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.osgi.service.condpermadmin; |
| |
| import java.util.Dictionary; |
| |
| /** |
| * The interface implemented by a Condition. Conditions are bound to Permissions |
| * using Conditional Permission Info. The Permissions of a ConditionalPermission |
| * Info can only be used if the associated Conditions are satisfied. |
| * |
| * @version $Revision: 1.13 $ |
| */ |
| public interface Condition { |
| /** |
| * A Condition object that will always evaluate to true and that is never |
| * postponed. |
| */ |
| public final static Condition TRUE = new BooleanCondition(true); |
| |
| /** |
| * A Condition object that will always evaluate to false and that is never |
| * postponed. |
| */ |
| public final static Condition FALSE = new BooleanCondition(false); |
| |
| /** |
| * Returns whether the evaluation must be postponed until the end of the |
| * permission check. This method returns <code>true</code> if the |
| * evaluation of the Condition must be postponed until the end of the |
| * permission check. If this method returns <code>false</code>, this |
| * Condition must be able to directly answer the {@link #isSatisfied()} |
| * method. In other words, isSatisfied() will return very quickly since no |
| * external sources, such as for example users, need to be consulted. |
| * |
| * @return <code>true</code> to indicate the evaluation must be postponed. |
| * Otherwise, <code>false</code> if the evaluation can be |
| * immediately performed. |
| */ |
| boolean isPostponed(); |
| |
| /** |
| * Returns whether the Condition is satisfied. |
| * |
| * @return <code>true</code> to indicate the Conditions is satisfied. |
| * Otherwise, <code>false</code> if the Condition is not satisfied. |
| */ |
| boolean isSatisfied(); |
| |
| /** |
| * Returns whether the Condition is mutable. |
| * |
| * @return <code>true</code> to indicate the value returned by |
| * {@link #isSatisfied()} can change. Otherwise, <code>false</code> |
| * if the value returned by {@link #isSatisfied()} will not change. |
| */ |
| boolean isMutable(); |
| |
| /** |
| * Returns whether a the set of Conditions are satisfied. Although this |
| * method is not static, it must be implemented as if it were static. All of |
| * the passed Conditions will be of the same type and will correspond to the |
| * class type of the object on which this method is invoked. |
| * |
| * @param conditions The array of Conditions. |
| * @param context A Dictionary object that implementors can use to track |
| * state. If this method is invoked multiple times in the same |
| * permission evaluation, the same Dictionary will be passed multiple |
| * times. The SecurityManager treats this Dictionary as an opaque |
| * object and simply creates an empty dictionary and passes it to |
| * subsequent invocations if multiple invocatios are needed. |
| * @return <code>true</code> if all the Conditions are satisfied. |
| * Otherwise, <code>false</code> if one of the Conditions is not |
| * satisfied. |
| */ |
| boolean isSatisfied(Condition conditions[], Dictionary context); |
| |
| } |
| |
| /** |
| * Package internal class used to define the {@link Condition#FALSE} and |
| * {@link Condition#TRUE} constants. |
| */ |
| final class BooleanCondition implements Condition { |
| final boolean satisfied; |
| |
| BooleanCondition(boolean satisfied) { |
| this.satisfied = satisfied; |
| } |
| |
| public boolean isPostponed() { |
| return false; |
| } |
| |
| public boolean isSatisfied() { |
| return satisfied; |
| } |
| |
| public boolean isMutable() { |
| return false; |
| } |
| |
| public boolean isSatisfied(Condition[] conds, Dictionary context) { |
| for (int i = 0; i < conds.length; i++) { |
| if (!conds[i].isSatisfied()) |
| return false; |
| } |
| return true; |
| } |
| |
| } |