/*

  * Copyright 2008 Les Hazlewood

  *

  * 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.apache.shiro.session.mgt;

 import java.io.Serializable;

 /**

  * A {@code SessionKey} is a key that allows look-up of any particular {@link org.apache.shiro.session.Session Session}

  * instance.  This is not to be confused what is probably better recognized as a session <em>attribute</em> key - a key

  * that is used to acquire a session attribute via the

  * {@link org.apache.shiro.session.Session#getAttribute(Object) Session.getAttribute} method.  A {@code SessionKey}

  * looks up a Session object directly.

  * <p/>

  * While a {@code SessionKey} allows lookup of <em>any</em> Session that might exist, this is not something in practice

  * done too often by most Shiro end-users.  Instead, it is usually more convenient to acquire the currently executing

  * {@code Subject}'s session via the {@link org.apache.shiro.subject.Subject#getSession} method.  This interface and

  * its usages are best suited for framework development.

  *

  * @since 1.0

  */

 public interface SessionKey {

     /**

      * Returns the id of the session to acquire.

      * <p/>

      * Acquiring sessions by ID only is a suitable strategy when sessions are natively managed by Shiro directly.

      * For example, the Servlet specification does not have an API that allows session acquisition by session ID, so

      * the session ID alone is not sufficient for ServletContainer-based SessionManager implementations.

      *

      * @return the id of the session to acquire.

      */

     Serializable getSessionId();

 }