| /* |
| * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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| */ |
| |
| package java.security.acl; |
| |
| import java.util.Enumeration; |
| import java.security.Principal; |
| |
| /** |
| * Interface representing an Access Control List (ACL). An Access |
| * Control List is a data structure used to guard access to |
| * resources.<p> |
| * |
| * An ACL can be thought of as a data structure with multiple ACL |
| * entries. Each ACL entry, of interface type AclEntry, contains a |
| * set of permissions associated with a particular principal. (A |
| * principal represents an entity such as an individual user or a |
| * group). Additionally, each ACL entry is specified as being either |
| * positive or negative. If positive, the permissions are to be |
| * granted to the associated principal. If negative, the permissions |
| * are to be denied.<p> |
| * |
| * The ACL Entries in each ACL observe the following rules: |
| * |
| * <ul> <li>Each principal can have at most one positive ACL entry and |
| * one negative entry; that is, multiple positive or negative ACL |
| * entries are not allowed for any principal. Each entry specifies |
| * the set of permissions that are to be granted (if positive) or |
| * denied (if negative). |
| * |
| * <li>If there is no entry for a particular principal, then the |
| * principal is considered to have a null (empty) permission set. |
| * |
| * <li>If there is a positive entry that grants a principal a |
| * particular permission, and a negative entry that denies the |
| * principal the same permission, the result is as though the |
| * permission was never granted or denied. |
| * |
| * <li>Individual permissions always override permissions of the |
| * group(s) to which the individual belongs. That is, individual |
| * negative permissions (specific denial of permissions) override the |
| * groups' positive permissions. And individual positive permissions |
| * override the groups' negative permissions. |
| * |
| * </ul> |
| * |
| * The {@code java.security.acl } package provides the |
| * interfaces to the ACL and related data structures (ACL entries, |
| * groups, permissions, etc.), and the {@code sun.security.acl } |
| * classes provide a default implementation of the interfaces. For |
| * example, {@code java.security.acl.Acl } provides the |
| * interface to an ACL and the {@code sun.security.acl.AclImpl } |
| * class provides the default implementation of the interface.<p> |
| * |
| * The {@code java.security.acl.Acl } interface extends the |
| * {@code java.security.acl.Owner } interface. The Owner |
| * interface is used to maintain a list of owners for each ACL. Only |
| * owners are allowed to modify an ACL. For example, only an owner can |
| * call the ACL's {@code addEntry} method to add a new ACL entry |
| * to the ACL. |
| * |
| * @see java.security.acl.AclEntry |
| * @see java.security.acl.Owner |
| * @see java.security.acl.Acl#getPermissions |
| * |
| * @author Satish Dharmaraj |
| */ |
| |
| public interface Acl extends Owner { |
| |
| /** |
| * Sets the name of this ACL. |
| * |
| * @param caller the principal invoking this method. It must be an |
| * owner of this ACL. |
| * |
| * @param name the name to be given to this ACL. |
| * |
| * @exception NotOwnerException if the caller principal |
| * is not an owner of this ACL. |
| * |
| * @see #getName |
| */ |
| public void setName(Principal caller, String name) |
| throws NotOwnerException; |
| |
| /** |
| * Returns the name of this ACL. |
| * |
| * @return the name of this ACL. |
| * |
| * @see #setName |
| */ |
| public String getName(); |
| |
| /** |
| * Adds an ACL entry to this ACL. An entry associates a principal |
| * (e.g., an individual or a group) with a set of |
| * permissions. Each principal can have at most one positive ACL |
| * entry (specifying permissions to be granted to the principal) |
| * and one negative ACL entry (specifying permissions to be |
| * denied). If there is already an ACL entry of the same type |
| * (negative or positive) already in the ACL, false is returned. |
| * |
| * @param caller the principal invoking this method. It must be an |
| * owner of this ACL. |
| * |
| * @param entry the ACL entry to be added to this ACL. |
| * |
| * @return true on success, false if an entry of the same type |
| * (positive or negative) for the same principal is already |
| * present in this ACL. |
| * |
| * @exception NotOwnerException if the caller principal |
| * is not an owner of this ACL. |
| */ |
| public boolean addEntry(Principal caller, AclEntry entry) |
| throws NotOwnerException; |
| |
| /** |
| * Removes an ACL entry from this ACL. |
| * |
| * @param caller the principal invoking this method. It must be an |
| * owner of this ACL. |
| * |
| * @param entry the ACL entry to be removed from this ACL. |
| * |
| * @return true on success, false if the entry is not part of this ACL. |
| * |
| * @exception NotOwnerException if the caller principal is not |
| * an owner of this Acl. |
| */ |
| public boolean removeEntry(Principal caller, AclEntry entry) |
| throws NotOwnerException; |
| |
| /** |
| * Returns an enumeration for the set of allowed permissions for the |
| * specified principal (representing an entity such as an individual or |
| * a group). This set of allowed permissions is calculated as |
| * follows: |
| * |
| * <ul> |
| * |
| * <li>If there is no entry in this Access Control List for the |
| * specified principal, an empty permission set is returned. |
| * |
| * <li>Otherwise, the principal's group permission sets are determined. |
| * (A principal can belong to one or more groups, where a group is a |
| * group of principals, represented by the Group interface.) |
| * The group positive permission set is the union of all |
| * the positive permissions of each group that the principal belongs to. |
| * The group negative permission set is the union of all |
| * the negative permissions of each group that the principal belongs to. |
| * If there is a specific permission that occurs in both |
| * the positive permission set and the negative permission set, |
| * it is removed from both.<p> |
| * |
| * The individual positive and negative permission sets are also |
| * determined. The positive permission set contains the permissions |
| * specified in the positive ACL entry (if any) for the principal. |
| * Similarly, the negative permission set contains the permissions |
| * specified in the negative ACL entry (if any) for the principal. |
| * The individual positive (or negative) permission set is considered |
| * to be null if there is not a positive (negative) ACL entry for the |
| * principal in this ACL.<p> |
| * |
| * The set of permissions granted to the principal is then calculated |
| * using the simple rule that individual permissions always override |
| * the group permissions. That is, the principal's individual negative |
| * permission set (specific denial of permissions) overrides the group |
| * positive permission set, and the principal's individual positive |
| * permission set overrides the group negative permission set. |
| * |
| * </ul> |
| * |
| * @param user the principal whose permission set is to be returned. |
| * |
| * @return the permission set specifying the permissions the principal |
| * is allowed. |
| */ |
| public Enumeration<Permission> getPermissions(Principal user); |
| |
| /** |
| * Returns an enumeration of the entries in this ACL. Each element in |
| * the enumeration is of type AclEntry. |
| * |
| * @return an enumeration of the entries in this ACL. |
| */ |
| public Enumeration<AclEntry> entries(); |
| |
| /** |
| * Checks whether or not the specified principal has the specified |
| * permission. If it does, true is returned, otherwise false is returned. |
| * |
| * More specifically, this method checks whether the passed permission |
| * is a member of the allowed permission set of the specified principal. |
| * The allowed permission set is determined by the same algorithm as is |
| * used by the {@code getPermissions} method. |
| * |
| * @param principal the principal, assumed to be a valid authenticated |
| * Principal. |
| * |
| * @param permission the permission to be checked for. |
| * |
| * @return true if the principal has the specified permission, false |
| * otherwise. |
| * |
| * @see #getPermissions |
| */ |
| public boolean checkPermission(Principal principal, Permission permission); |
| |
| /** |
| * Returns a string representation of the |
| * ACL contents. |
| * |
| * @return a string representation of the ACL contents. |
| */ |
| public String toString(); |
| } |
