EventFactory


1   /*
2    * $Header: /cvsroot/jdbforms/dbforms/src/org/dbforms/event/EventFactory.java,v 1.28 2005/02/19 21:26:29 hkollmann Exp $
3    * $Revision: 1.28 $
4    * $Date: 2005/02/19 21:26:29 $
5    *
6    * DbForms - a Rapid Application Development Framework
7    * Copyright (C) 2001 Joachim Peer <joepeer@excite.com>
8    *
9    * This library is free software; you can redistribute it and/or
10   * modify it under the terms of the GNU Lesser General Public
11   * License as published by the Free Software Foundation; either
12   * 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,
15   * but WITHOUT ANY WARRANTY; without even the implied warranty of
16   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17   * Lesser General Public License for more details.
18   *
19   * You should have received a copy of the GNU Lesser General Public
20   * License along with this library; if not, write to the Free Software
21   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
22   */
23  
24  package org.dbforms.event;
25  
26  import org.apache.commons.logging.Log;
27  import org.apache.commons.logging.LogFactory;
28  
29  import org.dbforms.config.DbFormsConfig;
30  import org.dbforms.config.DbFormsConfigRegistry;
31  import org.dbforms.config.EventInfo;
32  import org.dbforms.config.Table;
33  import org.dbforms.config.TableEvents;
34  
35  import org.dbforms.event.eventtype.EventTypeUtil;
36  
37  import org.dbforms.util.ReflectionUtil;
38  import org.dbforms.util.Util;
39  
40  import java.util.HashMap  ;
41  import java.util.Properties  ;
42  
43  import javax.servlet.http.HttpServletRequest  ;
44  
45  
46  
47  /**
48   * The EventFactory abstract class provides the interface and the
49   * implementation     of protected methods used by eventFactory subclasses
50   * (see NavEventFactory and DatabaseEventFactory).
51   *
52   * @author Luca Fossato
53   *
54   */
55  public abstract class EventFactory {
56     /** logging category */
57     private static Log logCat = LogFactory.getLog(EventFactory.class);
58  
59     /** classes used as "non keyInfo" constructor arguments types */
60     static final Class  [] constructorArgsTypes = new Class  [] {
61                                                              String  .class,
62                                                              HttpServletRequest  .class,
63                                                              DbFormsConfig.class
64                                                           };
65  
66     /** map of supported event */
67     protected HashMap   eventInfoMap = null;
68  
69     /**
70      * Creates a new EventFactory object.
71      */
72     protected EventFactory() {
73        eventInfoMap = new HashMap  ();
74  
75        try {
76           initializeEvents();
77        } catch (Exception   e) {
78           logCat.error("::EventFactory - cannot initialize the factory events", e);
79        }
80     }
81  
82     /**
83      * Create and return a new event.
84      *
85      * @param action the action string that identifies the web event
86      * @param request the HttpServletRequest object
87      * @param config the DbForms config object
88      *
89      * @return a new navigation event
90      */
91     public abstract WebEvent createEvent(String               action,
92                                          HttpServletRequest   request,
93                                          DbFormsConfig      config);
94  
95  
96     /**
97      * Add a new EventInfo object into the factory. <br>
98      * The EventInfo name must be unique.
99      *
100     * @param einfo the EventInfo object to add to
101     */
102    public void addEventInfo(EventInfo einfo) {
103       if (eventInfoMap != null) {
104          // note: events are registered using their id value (if that value is not null),
105          // or their type value (if the id is null or empty).
106          String   id = einfo.getId();
107 
108          // event info override;
109          if (eventInfoMap.containsKey(id)) {
110             EventInfo prevEinfo = (EventInfo) eventInfoMap.get(id);
111 
112             if (prevEinfo != null) {
113                String   prevClassName = prevEinfo.getClassName();
114                logCat.warn(new StringBuffer  ("::addEventInfo - the event information having id, class [").append(id).append(", ").append(einfo
115                                                                                                                                         .getClassName()).append("] overrides the event class [").append(prevClassName).append("]").toString());
116             }
117          }
118 
119          // event info registration;
120          eventInfoMap.put(id, einfo);
121          logCat.info(new StringBuffer  ("::addEventInfo - event info having id, type, class [").append(id).append(", ").append(einfo
122                                                                                                                              .getType()).append(", ").append(einfo
123                                                                                                                                                              .getClassName()).append("] registered"));
124       }
125    }
126 
127 
128    /**
129     * PROTECTED methods here
130     *
131     * @throws Exception DOCUMENT ME!
132     */
133    /**
134     * Initialize the default events.
135     *
136     * @exception Exception if any error occurs
137     */
138    protected abstract void initializeEvents() throws Exception  ;
139 
140 
141    /**
142     * Instance a new DatabaseEvent object.
143     *
144     * @param einfo the EventInfo object
145     * @param constructorArgsTypes array of constructor argument classes
146     * @param constructorArgs array of constructor argument objects
147     *
148     * @return the event object, or null if any problem occurs
149     */
150    protected WebEvent getEvent(EventInfo einfo,
151                                Class  []   aconstructorArgsTypes,
152                                Object  []  constructorArgs) {
153       WebEvent event = null;
154 
155       if (einfo != null) {
156          try {
157             event = (WebEvent) ReflectionUtil.newInstance(einfo.getClassName(),
158                                                           aconstructorArgsTypes,
159                                                           constructorArgs);
160 
161             // set a new Properties object into the event;
162             event.setProperties(new Properties  (einfo.getProperties()));
163             event.setType(einfo.getType());
164          } catch (Exception   e) {
165             logCat.error("::getEvent - cannot create the new event [" + einfo
166                          + "]", e);
167          }
168       }
169 
170       return event;
171    }
172 
173 
174    /**
175     * Get the Event identifier from the destination table related to the input
176     * action string
177     *
178     * @param request the request object
179     * @param action the action string
180     *
181     * @return the Event identifier  from the destination table, or null if any
182     *         error occurs
183     */
184    protected String   getEventIdFromDestinationTable(HttpServletRequest   request,
185                                                    String               action) {
186       DbFormsConfig config    = null;
187       Table         table     = null;
188       String          eventId   = null;
189       String          eventType = EventTypeUtil.getEventType(action)
190                                              .getEventType();
191 
192       try {
193          config = DbFormsConfigRegistry.instance()
194                                        .lookup();
195       } catch (Exception   e) {
196          logCat.error("::getEventIdFromDestinationTable - cannot get the config object from the DbFormsConfigRegistry");
197       }
198 
199       if (config != null) {
200          // try to retrieve a valid  target table name from the request;
201          // if it's null, try to retrieve the table id from the action string.
202          String   tableName = EventHelper.getDestinationTableName(request, action);
203 
204          if (!Util.isNull(tableName)) {
205             table = config.getTableByName(tableName);
206          } else {
207             int tableId = EventHelper.getTableId(action);
208             table = config.getTable(tableId);
209          }
210 
211          if (!Util.isNull(eventType)) {
212             TableEvents tableEvents;
213 
214             if (table != null) {
215                tableEvents = table.getTableEvents();
216             } else {
217                tableEvents = new TableEvents();
218             }
219 
220             eventId = tableEvents.getEventId(eventType);
221          }
222       }
223 
224       logCat.info("::getEventIdFromDestinationTable - eventId = [" + eventId
225                   + "]");
226 
227       return eventId;
228    }
229 
230 
231    /**
232     * Get the Event identifier from the destination table related to the input
233     * action string
234     *
235     * @param table the table object
236     * @param action the action string
237     *
238     * @return the Event identifier  from the destination table, or null if any
239     *         error occurs
240     */
241    protected String   getEventIdFromDestinationTable(Table  table,
242                                                    String   action) {
243       TableEvents tableEvents = table.getTableEvents();
244       String        eventType = EventTypeUtil.getEventType(action)
245                                            .getEventType();
246       String        eventId = tableEvents.getEventId(eventType);
247 
248       logCat.info("::getEventIdFromDestinationTable - eventId = [" + eventId
249                   + "]");
250 
251       return eventId;
252    }
253 
254 
255    /**
256     * Get the EventInfo object having the input identifier.
257     *
258     * @param id the EventInfo identifier
259     *
260     * @return the EventInfo object having the input identifier, or null if that
261     *         object does not exist
262     */
263    protected EventInfo getEventInfo(String   id) {
264       EventInfo einfo = null;
265 
266       if ((eventInfoMap != null) && (eventInfoMap.containsKey(id))) {
267          einfo = (EventInfo) eventInfoMap.get(id);
268       } else {
269          logCat.error("::getEventInfo - event having id [" + id
270                       + "] is not registered into the factory, returning a NULL event");
271       }
272 
273       return einfo;
274    }
275 }
276
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