/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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 org.apache.shiro.session.InvalidSessionException;

 import org.apache.shiro.session.Session;

 import java.io.Serializable;

 import java.util.Collection;

 import java.util.Date;

 /**

  * A DelegatingSession is a client-tier representation of a server side

  * {@link org.apache.shiro.session.Session Session}.

  * This implementation is basically a proxy to a server-side {@link NativeSessionManager NativeSessionManager},

  * which will return the proper results for each method call.

  * <p/>

  * <p>A <tt>DelegatingSession</tt> will cache data when appropriate to avoid a remote method invocation,

  * only communicating with the server when necessary.

  * <p/>

  * <p>Of course, if used in-process with a NativeSessionManager business POJO, as might be the case in a

  * web-based application where the web classes and server-side business pojos exist in the same

  * JVM, a remote method call will not be incurred.

  *

  * @since 0.1

  */

 public class DelegatingSession implements Session, Serializable {

     //TODO - complete JavaDoc

     private final SessionKey key;

     //cached fields to avoid a server-side method call if out-of-process:

     private Date startTimestamp = null;

     private String host = null;

     /**

      * Handle to the target NativeSessionManager that will support the delegate calls.

      */

     private final transient NativeSessionManager sessionManager;

     public DelegatingSession(NativeSessionManager sessionManager, SessionKey key) {

         if (sessionManager == null) {

             throw new IllegalArgumentException("sessionManager argument cannot be null.");

         }

         if (key == null) {

             throw new IllegalArgumentException("sessionKey argument cannot be null.");

         }

         if (key.getSessionId() == null) {

             String msg = "The " + DelegatingSession.class.getName() + " implementation requires that the " +

                     "SessionKey argument returns a non-null sessionId to support the " +

                     "Session.getId() invocations.";

             throw new IllegalArgumentException(msg);

         }

         this.sessionManager = sessionManager;

         this.key = key;

     }

     /**

      * @see org.apache.shiro.session.Session#getId()

      */

     public Serializable getId() {

         return key.getSessionId();

     }

     /**

      * @see org.apache.shiro.session.Session#getStartTimestamp()

      */

     public Date getStartTimestamp() {

         if (startTimestamp == null) {

             startTimestamp = sessionManager.getStartTimestamp(key);

         }

         return startTimestamp;

     }

     /**

      * @see org.apache.shiro.session.Session#getLastAccessTime()

      */

     public Date getLastAccessTime() {

         //can't cache - only business pojo knows the accurate time:

         return sessionManager.getLastAccessTime(key);

     }

     public long getTimeout() throws InvalidSessionException {

         return sessionManager.getTimeout(key);

     }

     public void setTimeout(long maxIdleTimeInMillis) throws InvalidSessionException {

         sessionManager.setTimeout(key, maxIdleTimeInMillis);

     }

     public String getHost() {

         if (host == null) {

             host = sessionManager.getHost(key);

         }

         return host;

     }

     /**

      * @see org.apache.shiro.session.Session#touch()

      */

     public void touch() throws InvalidSessionException {

         sessionManager.touch(key);

     }

     /**

      * @see org.apache.shiro.session.Session#stop()

      */

     public void stop() throws InvalidSessionException {

         sessionManager.stop(key);

     }

     /**

      * @see org.apache.shiro.session.Session#getAttributeKeys

      */

     public Collection<Object> getAttributeKeys() throws InvalidSessionException {

         return sessionManager.getAttributeKeys(key);

     }

     /**

      * @see org.apache.shiro.session.Session#getAttribute(Object key)

      */

     public Object getAttribute(Object attributeKey) throws InvalidSessionException {

         return sessionManager.getAttribute(this.key, attributeKey);

     }

     /**

      * @see Session#setAttribute(Object key, Object value)

      */

     public void setAttribute(Object attributeKey, Object value) throws InvalidSessionException {

         if (value == null) {

             removeAttribute(attributeKey);

         } else {

             sessionManager.setAttribute(this.key, attributeKey, value);

         }

     }

     /**

      * @see Session#removeAttribute(Object key)

      */

     public Object removeAttribute(Object attributeKey) throws InvalidSessionException {

         return sessionManager.removeAttribute(this.key, attributeKey);

     }

 }