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1   /* This file is part of the project "Hilbert II" - http://www.qedeq.org" target="alexandria_uri">http://www.qedeq.org
2    *
3    * Copyright 2000-2014,  Michael Meyling <mime@qedeq.org>.
4    *
5    * "Hilbert II" is free software; you can redistribute
6    * it and/or modify it under the terms of the GNU General Public
7    * License as published by the Free Software Foundation; either
8    * version 2 of the License, or (at your option) any later version.
9    *
10   * This program is distributed in the hope that it will be useful,
11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13   * GNU General Public License for more details.
14   */
15  
16  package org.qedeq.kernel.xml.handler.module;
17  
18  import org.qedeq.kernel.se.dto.module.FormulaVo;
19  import org.qedeq.kernel.xml.common.XmlSyntaxException;
20  import org.qedeq.kernel.xml.handler.common.AbstractSimpleHandler;
21  import org.qedeq.kernel.xml.handler.common.SimpleAttributes;
22  import org.qedeq.kernel.xml.handler.list.ElementHandler;
23  
24  
25  /**
26   * Parse formula.
27   *
28   * @author  Michael Meyling
29   */
30  public class FormulaHandler extends AbstractSimpleHandler {
31  
32      /** Value object for formula. */
33      private FormulaVo formula;
34  
35      /** Handles {@link org.qedeq.kernel.se.base.list.Element}s. */
36      private final ElementHandler elementHandler;
37  
38  
39      /**
40       * Handles formulas.
41       *
42       * @param   handler     Parent handler.
43       */
44      public FormulaHandler(final AbstractSimpleHandler handler) {
45          super(handler, "FORMULA");
46          elementHandler = new ElementHandler(this);
47      }
48  
49      public final void init() {
50          formula = null;
51      }
52  
53      /**
54       * Get parsed result.
55       *
56       * @return  FormulaOrTerm.
57       */
58      public final FormulaVo getFormula() {
59          return formula;
60      }
61  
62      public final void startElement(final String name, final SimpleAttributes attributes)
63              throws XmlSyntaxException {
64          if (getStartTag().equals(name)) {
65              // nothing to do
66          } else if (getLevel() > 1) {
67              changeHandler(elementHandler, name, attributes);
68          } else {
69              throw XmlSyntaxException.createUnexpectedTagException(name);
70          }
71      }
72  
73      public final void endElement(final String name) throws XmlSyntaxException {
74          if (getStartTag().equals(name)) {
75              formula = new FormulaVo(elementHandler.getElement());
76          } else if (getLevel() <= 1) {
77              throw XmlSyntaxException.createUnexpectedTagException(name);
78          }
79      }
80  
81  }