IterativeSubModel


1   /*
2    * Copyright (C) 2003  Stefan Armbruster [stefan@armbruster-it.de]
3    *
4    * This library is free software; you can redistribute it and/or
5    * modify it under the terms of the GNU Lesser General Public
6    * License as published by the Free Software Foundation; either
7    * version 2.1 of the License, or (at your option) any later version.
8    *
9    * This library is distributed in the hope that it will be useful,
10   * but WITHOUT ANY WARRANTY; without even the implied warranty of
11   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   * Lesser General Public License for more details.
13   *
14   * You should have received a copy of the GNU Lesser General Public
15   * License along with this library; if not, write to the Free Software
16   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
17   *
18   * $Id: IterativeSubModel.java,v 1.3 2004/02/01 05:16:27 christianc Exp $
19   */
20  package org.enhydra.barracuda.contrib.sam.models;
21  
22  import org.enhydra.barracuda.core.comp.*;
23  import org.apache.log4j.*;
24  import java.util.*;
25  
26  /**
27   * Assume a "supermodel" containing a List of Lists (a 2 dimensional structure).
28   * An outer ("enclosing") model iterates over the the 1st dimension. The IterativeSubModel
29   * asks the enclosing model for its current value and iterates over the 2nd dimension
30   * @author Stefan Armbruster
31   * @version $Id: IterativeSubModel.java,v 1.3 2004/02/01 05:16:27 christianc Exp $
32   */
33  public class IterativeSubModel extends IteratorModel {
34  
35      protected static Logger logger = Logger.getLogger(IterativeSubModel.class);
36  
37      /** reference to enclosing model */
38      protected TemplateModel enclosing;
39      protected String   key;
40  
41      /** initialize the model
42       * @param name Name of the model
43       * @param enclosing reference to surrounding model
44       */
45      public IterativeSubModel(String   name, String   key, TemplateModel enclosing) {
46          super(name);
47          this.enclosing = enclosing;
48          this.key = key;
49      }
50  
51      public void preIterate() {
52          if (enclosing==null) {
53              logger.error("you didn't specify a valid enclosing model");
54              return;
55          }
56          Object   referenceMain = enclosing.getItem(new TemplateDirective(null, null, key, null));
57          /*if (referenceMain == null) {
58              logger.error("the enclosing model (type: " + enclosing.getClass().getName() + ") doesn't have a " + key + " result for getItem");
59              return;
60          }*/
61  
62          // if enclosing model delivers a List, use it. Otherwise, get a list out of the reference by calling getListFromReference
63          Collection coll = null;
64          if (referenceMain instanceof Collection) {
65              logger.debug("List: " + (Collection)referenceMain);
66              coll = (Collection)referenceMain;
67          } else {
68              logger.info("the enclosing model (type: " + enclosing.getClass().getName() + ") doesn't deliver a Collection, so call getListFromReference");
69              coll = getListFromReference(referenceMain);
70          }
71          if (coll == null) {
72              logger.error("could not get a list from model " + enclosing.getClass().getName());
73          } else {
74              setIterator( coll.iterator() );
75          }
76          super.preIterate();
77      }
78  
79      /** dummy implementation, to be overridden in subclasses */
80      protected Collection getListFromReference(Object   ref) {
81          throw new UnsupportedOperationException  ("getListFromReference is not yet implemented");
82      }
83  
84      public Object   getItem(String   key) {
85          logger.debug("getting key : " + key);
86          return _current;
87      }
88  }
89
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