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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.base.list.Element;
19  import org.qedeq.kernel.se.base.module.Universal;
20  import org.qedeq.kernel.se.dto.module.UniversalVo;
21  import org.qedeq.kernel.xml.common.XmlSyntaxException;
22  import org.qedeq.kernel.xml.handler.common.AbstractSimpleHandler;
23  import org.qedeq.kernel.xml.handler.common.SimpleAttributes;
24  import org.qedeq.kernel.xml.handler.list.ElementHandler;
25  
26  
27  /**
28   * Parse a existential generalization rule usage.
29   *
30   * @author  Michael Meyling
31   */
32  public class UniversalHandler extends AbstractSimpleHandler {
33  
34      /** Rule value object. */
35      private Universal universal;
36  
37      /** Reference to previously proved formula. */
38      private String ref;
39  
40      /** Subject variable. */
41      private Element subjectVariable;
42  
43      /** Handle elements. */
44      private final ElementHandler elementHandler;
45  
46      /**
47       * Deals with definitions.
48       *
49       * @param   handler Parent handler.
50       */
51      public UniversalHandler(final AbstractSimpleHandler handler) {
52          super(handler, "UNIVERSAL");
53          elementHandler = new ElementHandler(this);
54      }
55  
56      public final void init() {
57          universal = null;
58          subjectVariable = null;
59          ref = null;
60      }
61  
62      /**
63       * Get rule object.
64       *
65       * @return  Universal generalization usage.
66       */
67      public final Universal getUniversalVo() {
68          return universal;
69      }
70  
71      public final void startElement(final String name, final SimpleAttributes attributes)
72              throws XmlSyntaxException {
73          if (getStartTag().equals(name)) {
74              ref = attributes.getString("ref");
75          } else if ("VAR".equals(name)) {
76              changeHandler(elementHandler, name, attributes);
77          } else {
78              throw XmlSyntaxException.createUnexpectedTagException(name);
79          }
80      }
81  
82      public final void endElement(final String name) throws XmlSyntaxException {
83          if (getStartTag().equals(name)) {
84              universal = new UniversalVo(ref, subjectVariable);
85          } else if ("VAR".equals(name)) {
86              subjectVariable = elementHandler.getElement();
87          } else {
88              throw XmlSyntaxException.createUnexpectedTagException(name);
89          }
90      }
91  
92  }