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Java > Open Source Codes > de > laures > cewolf > storage > LongTermSessionStorage


1 /* ================================================================
2  * Cewolf : Chart enabling Web Objects Framework
3  * ================================================================
4  *
5  * Project Info: http://cewolf.sourceforge.net
6  * Project Lead: Guido Laures (guido@laures.de);
7  *
8  * (C) Copyright 2002, by Guido Laures
9  *
10  * This library is free software; you can redistribute it and/or modify it under the terms
11  * of the GNU Lesser General Public License as published by the Free Software Foundation;
12  * either version 2.1 of the License, or (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
15  * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
16  * See the GNU Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public License along with this
19  * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
20  * Boston, MA 02111-1307, USA.
21  */
22 package de.laures.cewolf.storage;
23
24 import java.io.Serializable JavaDoc;
25
26 import javax.servlet.ServletContext JavaDoc;
27 import javax.servlet.http.HttpServletRequest JavaDoc;
28 import javax.servlet.http.HttpSession JavaDoc;
29 import javax.servlet.jsp.PageContext JavaDoc;
30
31 import de.laures.cewolf.CewolfException;
32 import de.laures.cewolf.ChartImage;
33 import de.laures.cewolf.Storage;
34 import de.laures.cewolf.taglib.util.KeyGenerator;
35
36 /**
37  * Storage stores images in session, but expires them after a certain time.
38  * This expiration time defaults to 300 seconds, and can be changed by adding
39  * the timeout="xxx" parameter to <cewolf:img> and <cewolf:legend> tags.
40  *
41  * @author brianf
42  */
43 public class LongTermSessionStorage implements Storage
44 {
45  
46   public final String JavaDoc getKey( ChartImage cid )
47   {
48     return String.valueOf(KeyGenerator.generateKey((Serializable JavaDoc) cid));
49   }
50
51   /*
52    * (non-Javadoc)
53    *
54    * @see de.laures.cewolf.Storage#storeChartImage(de.laures.cewolf.ChartImage,
55    * javax.servlet.jsp.PageContext)
56    */
57   public String JavaDoc storeChartImage( ChartImage chartImage, PageContext JavaDoc pageContext ) throws CewolfException
58   {
59     HttpSession JavaDoc session = pageContext.getSession();
60     SessionStorageGroup ssg = (SessionStorageGroup) session.getAttribute("CewolfCharts");
61     if ( ssg == null )
62     {
63       ssg = new SessionStorageGroup();
64       session.setAttribute("CewolfCharts", ssg);
65     }
66     String JavaDoc cid = getKey(chartImage);
67     SessionStorageItem ssi = new SessionStorageItem(chartImage, cid, chartImage.getTimeoutTime());
68     ssg.put(cid, ssi);
69
70     return cid;
71   }
72
73   /*
74    * (non-Javadoc)
75    *
76    * @see de.laures.cewolf.Storage#getChartImage(java.lang.String,
77    * javax.servlet.http.HttpServletRequest)
78    */
79   public ChartImage getChartImage( String JavaDoc id, HttpServletRequest JavaDoc request )
80   {
81     HttpSession JavaDoc session = request.getSession();
82     ChartImage chart = null;
83     SessionStorageGroup ssg = (SessionStorageGroup) session.getAttribute("CewolfCharts");
84     if ( ssg != null )
85     {
86       SessionStorageItem ssi = (SessionStorageItem) ssg.get(id);
87       if ( ssi != null )
88       {
89         chart = ssi.getChart();
90       }
91     }
92
93     return chart;
94   }
95   /*
96    * (non-Javadoc)
97    *
98    * @see de.laures.cewolf.Storage#init(javax.servlet.ServletContext)
99    */
100   public void init( ServletContext JavaDoc servletContext ) throws CewolfException {
101   }
102
103   /**
104    * @see de.laures.cewolf.Storage#removeChartImage(java.lang.String, javax.servlet.jsp.PageContext)
105    */
106   public String JavaDoc removeChartImage(String JavaDoc cid, HttpServletRequest JavaDoc request) throws CewolfException {
107       HttpSession JavaDoc session = request.getSession();
108       // No session exit
109 if (session == null)
110       {
111           return cid;
112       }
113       SessionStorageGroup ssg = (SessionStorageGroup) session.getAttribute("CewolfCharts");
114       if ( ssg == null )
115       {
116           // No group exit
117 return cid;
118       }
119       ssg.remove(cid);
120       return cid;
121   }
122 }
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