1    
2    /* ====================================================================
3     * The Apache Software License, Version 1.1
4     *
5     * Copyright (c) 2002 The Apache Software Foundation.  All rights
6     * reserved.
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9     * modification, are permitted provided that the following conditions
10    * are met:
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12    * 1. Redistributions of source code must retain the above copyright
13    *    notice, this list of conditions and the following disclaimer.
14    *
15    * 2. Redistributions in binary form must reproduce the above copyright
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21    *    if any, must include the following acknowledgment:
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24    *    Alternately, this acknowledgment may appear in the software itself,
25    *    if and wherever such third-party acknowledgments normally appear.
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27    * 4. The names "Apache" and "Apache Software Foundation" and
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55   
56   package org.apache.poi.hssf.eventmodel;
57   
58   import java.util.HashMap;
59   import java.util.List;
60   import java.util.ArrayList;
61   
62   import org.apache.poi.hssf.record.Record;
63   import org.apache.poi.hssf.record.RecordFactory;
64   
65   /**
66    * An HSSFRequest object should be constructed registering an instance or multiple
67    * instances of HSSFListener with each Record.sid you wish to listen for.
68    *
69    * @see org.apache.poi.hssf.eventmodel.HSSFEventFactory
70    * @see org.apache.poi.hssf.eventmodel.HSSFListener
71    * @see org.apache.poi.hssf.dev.EFHSSF
72    * @author  andy
73    */
74   
75   public class HSSFRequest
76   {
77       private HashMap records;
78   
79       /** Creates a new instance of HSSFRequest */
80   
81       public HSSFRequest()
82       {
83           records =
84               new HashMap(50);   // most folks won't listen for too many of these
85       }
86   
87       /**
88        * add an event listener for a particular record type.  The trick is you have to know
89        * what the records are for or just start with our examples and build on them.  Alternatively,
90        * you CAN call addListenerForAllRecords and you'll recieve ALL record events in one listener,
91        * but if you like to squeeze every last byte of efficiency out of life you my not like this.
92        * (its sure as heck what I plan to do)
93        *
94        * @see #addListenerForAllRecords(HSSFListener)
95        *
96        * @param lsnr      for the event
97        * @param sid       identifier for the record type this is the .sid static member on the individual records
98        *        for example req.addListener(myListener, BOFRecord.sid)
99        */
100  
101      public void addListener(HSSFListener lsnr, short sid)
102      {
103          List   list = null;
104          Object obj  = records.get(new Short(sid));
105  
106          if (obj != null)
107          {
108              list = ( List ) obj;
109          }
110          else
111          {
112              list = new ArrayList(
113                  1);   // probably most people will use one listener
114              list.add(lsnr);
115              records.put(new Short(sid), list);
116          }
117      }
118  
119      /**
120       * This is the equivilent of calling addListener(myListener, sid) for EVERY
121       * record in the org.apache.poi.hssf.record package. This is for lazy
122       * people like me. You can call this more than once with more than one listener, but
123       * that seems like a bad thing to do from a practice-perspective unless you have a
124       * compelling reason to do so (like maybe you send the event two places or log it or
125       * something?).
126       *
127       * @param lsnr      a single listener to associate with ALL records
128       */
129  
130      public void addListenerForAllRecords(HSSFListener lsnr)
131      {
132          short[] rectypes = RecordFactory.getAllKnownRecordSIDs();
133  
134          for (int k = 0; k < rectypes.length; k++)
135          {
136              addListener(lsnr, rectypes[ k ]);
137          }
138      }
139  
140      /**
141       * called by HSSFEventFactory, passes the Record to each listener associated with
142       * a record.sid.
143       */
144  
145      protected void processRecord(Record rec)
146      {
147          Object obj = records.get(new Short(rec.getSid()));
148  
149          if (obj != null)
150          {
151              List listeners = ( List ) obj;
152  
153              for (int k = 0; k < listeners.size(); k++)
154              {
155                  HSSFListener listener = ( HSSFListener ) listeners.get(k);
156  
157                  listener.processRecord(rec);
158              }
159          }
160      }
161  }
162