/* * Copyright (c) 2007, 2009, 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 * or visit www.oracle.com if you need additional information or have any * questions. */ package java.nio.file.attribute; import java.io.IOException; /** * An object to lookup user and group principals by name. A {@link UserPrincipal} * represents an identity that may be used to determine access rights to objects * in a file system. A {@link GroupPrincipal} represents a <em>group identity</em>. * A {@code UserPrincipalLookupService} defines methods to lookup identities by * name or group name (which are typically user or account names). Whether names * and group names are case sensitive or not depends on the implementation. * The exact definition of a group is implementation specific but typically a * group represents an identity created for administrative purposes so as to * determine the access rights for the members of the group. In particular it is * implementation specific if the <em>namespace</em> for names and groups is the * same or is distinct. To ensure consistent and correct behavior across * platforms it is recommended that this API be used as if the namespaces are * distinct. In other words, the {@link #lookupPrincipalByName * lookupPrincipalByName} should be used to lookup users, and {@link * #lookupPrincipalByGroupName lookupPrincipalByGroupName} should be used to * lookup groups. * * @since 1.7 * * @see java.nio.file.FileSystem#getUserPrincipalLookupService */ public abstract class UserPrincipalLookupService {     /**     * Initializes a new instance of this class.     */    protected UserPrincipalLookupService() {    }     /**     * Lookup a user principal by name.     *     * @param   name     *          the string representation of the user principal to lookup     *     * @return  a user principal     *     * @throws  UserPrincipalNotFoundException     *          the principal does not exist     * @throws  IOException     *          if an I/O error occurs     * @throws  SecurityException     *          In the case of the default provider, and a security manager is     *          installed, it checks {@link RuntimePermission}<tt>("lookupUserInformation")</tt>     */    public abstract UserPrincipal lookupPrincipalByName(String name)        throws IOException;     /**     * Lookup a group principal by group name.     *     * <p> Where an implementation does not support any notion of group then     * this method always throws {@link UserPrincipalNotFoundException}. Where     * the namespace for user accounts and groups is the same, then this method     * is identical to invoking {@link #lookupPrincipalByName     * lookupPrincipalByName}.     *     * @param   group     *          the string representation of the group to lookup     *     * @return  a group principal     *     * @throws  UserPrincipalNotFoundException     *          the principal does not exist or is not a group     * @throws  IOException     *          if an I/O error occurs     * @throws  SecurityException     *          In the case of the default provider, and a security manager is     *          installed, it checks {@link RuntimePermission}<tt>("lookupUserInformation")</tt>     */    public abstract GroupPrincipal lookupPrincipalByGroupName(String group)        throws IOException;}