001/* Element.java --
002   Copyright (C) 2005 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.swing.text.html.parser;
040
041import gnu.javax.swing.text.html.parser.support.gnuStringIntMapper;
042
043import java.io.Serializable;
044
045import java.util.BitSet;
046
047/**
048 * <p>
049 * Stores the element information, obtained by parsing SGML DTD
050 * tag <code>&lt;!ELEMENT .. &gt;</code>. This class has no public
051 * constructor and can only be instantiated using the
052 * {@link javax.swing.text.html.parser.DTD } methods</p>
053 *
054 * <p>SGML defines elements that represent structures or
055 * behavior. An element typically consists of a start tag, content, and an
056 * end tag. Hence the elements are not tags. The HTML 4.0 definition specifies
057 * that some elements are not required to have the end tags. Also, some
058 * HTML elements (like <code>&lt;hr&gt;</code>) have no content. Element names
059 * are case sensitive.</p>
060 * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
061 */
062public final class Element
063  implements DTDConstants, Serializable
064{
065  /**
066   * Package level mapper between type names and they string values.
067   */
068  static final gnuStringIntMapper mapper =
069    new gnuStringIntMapper()
070    {
071      protected void create()
072      {
073        add("CDATA", DTDConstants.CDATA);
074        add("RCDATA", DTDConstants.RCDATA);
075        add("EMPTY", DTDConstants.EMPTY);
076        add("ANY", DTDConstants.ANY);
077      }
078    };
079
080  /** Use serialVersionUID for interoperability. */
081  private static final long serialVersionUID = -6717939384601675586L;
082
083  /**
084   * The element attributes.
085   */
086  public AttributeList atts;
087
088  /**
089   * Contains refernces to elements that must NOT occur inside this element,
090   * at any level of hierarchy.
091   */
092  public BitSet exclusions;
093
094  /**
095   * Contains refernces to elements that must CAN occur inside this element,
096   * at any level of hierarchy.
097   */
098  public BitSet inclusions;
099
100  /**
101   * The content model, defining elements, entities and DTD text
102   * that may/may not occur inside this element.
103   */
104  public ContentModel content;
105
106  /**
107   * A field to store additional user data for this Element.
108   */
109  public Object data;
110
111  /**
112   * The element name.
113   */
114  public String name;
115
116  /**
117   * True is this element need not to have the closing tag, false
118   * otherwise. The HTML 4.0 definition specifies
119   * that some elements (like <code>&lt;hr&gt;</code>are
120   * not required to have the end tags.
121   */
122  public boolean oEnd;
123
124  /**
125   * True is this element need not to have the starting tag, false
126   * otherwise. The HTML 4.0 definition specifies
127   * that some elements (like <code>&lt;head&gt;</code> or
128   * <code>&lt;body&gt;</code>) are
129   * not required to have the start tags.
130
131   */
132  public boolean oStart;
133
134  /**
135   * This field contains the unique integer identifier of this Element,
136   * used to refer the element (more exactly, the element flag)
137   * in <code>inclusions</code> and <code>exclusions</code> bit set.
138   */
139  public int index;
140
141  /**
142   * The element type, containing value, defined in DTDConstants.
143   * In this implementation, the element type can be
144   * CDATA, RCDATA, EMPTY or ANY.
145   */
146  public int type;
147
148  /**
149   * The default constructor must have package level access in this
150   * class. Use DTD.defineElement(..) to create an element when required.
151   */
152  Element()
153  {
154    // Nothing to do here.
155  }
156
157  /**
158   * Converts the string representation of the element type
159   * into its unique integer identifier, defined in DTDConstants.
160   * @param a_type A name of the type
161   * @return DTDConstants.CDATA, DTDConstants.RCDATA, DTDConstants.EMPTY,
162   * DTDConstants.ANY or null if the type name is not
163   * "CDATA", "RCDATA", "EMPTY" or "ANY". This function is case sensitive.
164   * @throws NullPointerException if <code>a_type</code> is null.
165   */
166  public static int name2type(String a_type)
167  {
168    return mapper.get(a_type);
169  }
170
171  /**
172   * Get the element attribute by name.
173   * @param attribute the attribute name, case insensitive.
174   * @return the correspoding attribute of this element. The class,
175   * for storing as attribute list, as a single attribute, is used to
176   * store a single attribute in this case.
177   * @throws NullPointerException if the attribute name is null.
178   */
179  public AttributeList getAttribute(String attribute)
180  {
181    AttributeList a = atts;
182
183    while (a != null && !attribute.equalsIgnoreCase(a.name))
184      a = a.next;
185
186    return a;
187  }
188
189  /**
190   * Get the element attribute by its value.
191   * @param a_value the attribute value, case insensitive.
192   * @return the correspoding attribute of this element. The class,
193   * for storing as attribute list, as a single attribute, is used to
194   * store a single attribute in this case. If there are several
195   * attributes with the same value, there is no garranty, which one
196   * is returned.
197   */
198  public AttributeList getAttributeByValue(String a_value)
199  {
200    AttributeList a = atts;
201
202    if (a_value == null)
203      {
204        while (a != null)
205          {
206            if (a.value == null)
207              return a;
208
209            a = a.next;
210          }
211      }
212    else
213      {
214        while (a != null)
215          {
216            if (a.value != null && a_value.equalsIgnoreCase(a.value))
217              return a;
218
219            a = a.next;
220          }
221      }
222
223    return null;
224  }
225
226  /**
227   * Get all attributes of this document as an attribute list.
228   * @return The attribute list.
229   */
230  public AttributeList getAttributes()
231  {
232    return atts;
233  }
234
235  /**
236   * Get the content model, defining elements, entities and DTD text
237   * that may/may not occur inside this element.
238   */
239  public ContentModel getContent()
240  {
241    return content;
242  }
243
244  /**
245   * Returns true for the element with no content.
246   * Empty elements are defined with the SGML DTD keyword "EMPTY".
247   * @return true if content model field (content) method is equal to
248   * null or its method empty() returns true.
249   */
250  public boolean isEmpty()
251  {
252    return content == null || content.empty();
253  }
254
255  /**
256   * Get the unique integer identifier of this Element,
257   * used to refer the element (more exactly, the element flag)
258   * in <code>inclusions</code> and <code>exclusions</code> bit set.
259   * WARNING: This value may not be the same between different
260   * implementations.
261   */
262  public int getIndex()
263  {
264    return index;
265  }
266
267  /**
268   * Get the element name.
269   */
270  public String getName()
271  {
272    return name;
273  }
274
275  /**
276   * Get the element type.
277   * @return one of the values, defined DTDConstants.
278   * In this implementation, the element type can be
279   * CDATA, RCDATA, EMPTY or ANY.
280   */
281  public int getType()
282  {
283    return type;
284  }
285
286  /**
287   * True is this element need not to have the starting tag, false
288   * otherwise.s element need not to have the closing tag, false
289   * otherwise. The HTML 4.0 definition specifies
290   * that some elements (like <code>&lt;hr&gt;</code>are
291   * not required to have the end tags.
292   */
293  public boolean omitEnd()
294  {
295    return oEnd;
296  }
297
298  /**
299   * True is this element need not to have the closing tag, false
300   * otherwise. The HTML 4.0 definition specifies
301   * that some elements (like <code>&lt;head&gt;</code> or
302   * <code>&lt;body&gt;</code>) are
303   * not required to have the start tags.
304   */
305  public boolean omitStart()
306  {
307    return oStart;
308  }
309
310  /**
311   * Returns the name of this element.
312   */
313  public String toString()
314  {
315    return name;
316  }
317}