001/* 
002    Licensed to the Apache Software Foundation (ASF) under one
003    or more contributor license agreements.  See the NOTICE file
004    distributed with this work for additional information
005    regarding copyright ownership.  The ASF licenses this file
006    to you under the Apache License, Version 2.0 (the
007    "License"); you may not use this file except in compliance
008    with the License.  You may obtain a copy of the License at
009
010       http://www.apache.org/licenses/LICENSE-2.0
011
012    Unless required by applicable law or agreed to in writing,
013    software distributed under the License is distributed on an
014    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015    KIND, either express or implied.  See the License for the
016    specific language governing permissions and limitations
017    under the License.  
018 */
019package org.apache.wiki.plugin;
020
021import java.security.Principal;
022import java.util.HashMap;
023import java.util.Iterator;
024import java.util.Map;
025
026import org.apache.wiki.WikiContext;
027import org.apache.wiki.WikiEngine;
028import org.apache.wiki.WikiSession;
029import org.apache.wiki.api.exceptions.PluginException;
030import org.apache.wiki.api.plugin.WikiPlugin;
031
032/**
033 *  <p>Displays information about active wiki sessions. The parameter
034 *  <code>property</code> specifies what information is displayed.
035 *  If omitted, the number of sessions is returned.
036 *  
037 *  <p>Parameters : </p>
038 *  <ul>
039 *  <li><b>property</b> - specify what output to display, valid values are:</li>
040 *  <ul>
041 *    <li><code>users</code> - returns a comma-separated list of
042 *    users</li>
043 *    <li><code>distinctUsers</code> - will only show
044 *    distinct users.
045 *  </ul>
046 *  </ul>
047 *  @since 2.3.84
048 */
049public class SessionsPlugin
050    implements WikiPlugin
051{
052    /** The parameter name for setting the property value. */
053    public static final String PARAM_PROP = "property";
054    
055    /**
056     *  {@inheritDoc}
057     */
058    public String execute( WikiContext context, Map<String, String> params )
059        throws PluginException
060    {
061        WikiEngine engine = context.getEngine();
062        String prop = params.get( PARAM_PROP );
063        
064        if ( "users".equals( prop ) )
065        {
066            Principal[] principals = WikiSession.userPrincipals( engine );
067            StringBuilder s = new StringBuilder();
068            for ( int i = 0; i < principals.length; i++ )
069            {
070                s.append(principals[i].getName() + ", ");
071            }
072            // remove the last comma and blank :
073            return s.substring(0, s.length() - (s.length() > 2 ? 2 : 0) );
074        }
075
076        //
077        // show each user session only once (with a counter that indicates the
078        // number of sessions for each user)
079        if ("distinctUsers".equals(prop))
080        {
081            Principal[] principals = WikiSession.userPrincipals(engine);
082            // we do not assume that the principals are sorted, so first count
083            // them :
084            HashMap<String,Integer> distinctPrincipals = new HashMap<String,Integer>();
085            for (int i = 0; i < principals.length; i++)
086            {
087                String principalName = principals[i].getName();
088
089                if (distinctPrincipals.containsKey(principalName))
090                {
091                    // we already have an entry, increase the counter:
092                    int numSessions = distinctPrincipals.get(principalName).intValue();
093                    // store the new value:
094                    distinctPrincipals.put(principalName, ++numSessions);
095                }
096                else
097                {
098                    // first time we see this entry, add entry to HashMap with value 1
099                    distinctPrincipals.put(principalName, 1);
100                }
101            }
102            //
103            //
104            StringBuilder s = new StringBuilder();
105            Iterator<Map.Entry<String, Integer>> entries = distinctPrincipals.entrySet().iterator();
106            while (entries.hasNext())
107            {
108                Map.Entry<String, Integer> entry = entries.next();
109                s.append( entry.getKey().toString() + "(" + entry.getValue().toString() + "), " );
110            }
111            // remove the last comma and blank :
112            return s.substring(0, s.length() - 2);
113        }
114
115        return String.valueOf( WikiSession.sessions( engine ) );
116    }
117}