Initial revision

From-SVN: r102074

libjava/classpath/javax/swing/text/html/parser/DocumentParser.java

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+/* DocumentParser.java -- A parser for HTML documents.
+   Copyright (C) 2005 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package javax.swing.text.html.parser;
+
+import gnu.javax.swing.text.html.parser.htmlAttributeSet;
+import javax.swing.text.html.parser.Parser;
+
+import java.io.IOException;
+import java.io.Reader;
+
+import javax.swing.text.BadLocationException;
+import javax.swing.text.html.HTMLEditorKit;
+
+/**
+ * <p>A simple error-tolerant HTML parser that uses a DTD document
+ * to access data on the possible tokens, arguments and syntax.</p>
+ * <p> The parser reads an HTML content from a Reader and calls various
+ * notifying methods (which should be overridden in a subclass)
+ * when tags or data are encountered.</p>
+ * <p>Some HTML elements need no opening or closing tags. The
+ * task of this parser is to invoke the tag handling methods also when
+ * the tags are not explicitly specified and must be supposed using
+ * information, stored in the DTD.
+ * For  example, parsing the document
+ * <p>&lt;table&gt;&lt;tr&gt;&lt;td&gt;a&lt;td&gt;b&lt;td&gt;c&lt;/tr&gt; <br>
+ * will invoke exactly the handling methods exactly in the same order
+ * (and with the same parameters) as if parsing the document: <br>
+ * <em>&lt;html&gt;&lt;head&gt;&lt;/head&gt;&lt;body&gt;&lt;table&gt;&lt;
+ * tbody&gt;</em>&lt;tr&gt;&lt;td&gt;a<em>&lt;/td&gt;</em>&lt;td&gt;b<em>
+ * &lt;/td&gt;</em>&lt;td&gt;c<em>&lt;/td&gt;&lt;/tr&gt;</em>&lt;
+ * <em>/tbody&gt;&lt;/table&gt;&lt;/body&gt;&lt;/html&gt;</em></p>
+ * (supposed tags are given in italics). The parser also supports
+ * obsolete elements of HTML syntax.<p>
+ * </p>
+ * In this implementation, DocumentParser is directly derived from its
+ * ancestor without changes of functionality.
+ * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org)
+ */
+public class DocumentParser
+  extends Parser
+  implements DTDConstants
+{
+  /**
+   * The enclosed working parser class.
+   */
+  private class gnuParser
+    extends gnu.javax.swing.text.html.parser.support.Parser
+  {
+    private gnuParser(DTD d)
+    {
+      super(d);
+    }
+
+    protected final void handleComment(char[] comment)
+    {
+      parser.handleComment(comment);
+      callBack.handleComment(comment, hTag.where.startPosition);
+    }
+
+    protected final void handleEmptyTag(TagElement tag)
+      throws javax.swing.text.ChangedCharSetException
+    {
+      parser.handleEmptyTag(tag);
+      callBack.handleSimpleTag(tag.getHTMLTag(), getAttributes(),
+                               hTag.where.startPosition
+                              );
+    }
+
+    protected final void handleEndTag(TagElement tag)
+    {
+      parser.handleEndTag(tag);
+      callBack.handleEndTag(tag.getHTMLTag(), hTag.where.startPosition);
+    }
+
+    protected final void handleError(int line, String message)
+    {
+      parser.handleError(line, message);
+      callBack.handleError(message, hTag.where.startPosition);
+    }
+
+    protected final void handleStartTag(TagElement tag)
+    {
+      parser.handleStartTag(tag);
+      htmlAttributeSet attributes = gnu.getAttributes();
+
+      if (tag.fictional())
+        attributes.addAttribute(HTMLEditorKit.ParserCallback.IMPLIED,
+                                Boolean.TRUE
+                               );
+
+      callBack.handleStartTag(tag.getHTMLTag(), attributes,
+                              hTag.where.startPosition
+                             );
+    }
+
+    protected final void handleText(char[] text)
+    {
+      parser.handleText(text);
+      callBack.handleText(text, hTag.where.startPosition);
+    }
+
+    DTD getDTD()
+    {
+      return dtd;
+    }
+  }
+
+  /**
+   * This field is used to access the identically named
+   * methods of the outer class.
+   * This is package-private to avoid an accessor method.
+   */
+  DocumentParser parser = this;
+
+  /**
+   * The callback.
+   * This is package-private to avoid an accessor method.
+   */
+  HTMLEditorKit.ParserCallback callBack;
+
+  /**
+   * The reference to the working class of HTML parser that is
+   * actually used to parse the document.
+   * This is package-private to avoid an accessor method.
+   */
+  gnuParser gnu;
+
+  /**
+   * Creates a new parser that uses the given DTD to access data on the
+   * possible tokens, arguments and syntax. There is no single - step way
+   * to get a default DTD; you must either refer to the implementation -
+   * specific packages, write your own DTD or obtain the working instance
+   * of parser in other way, for example, by calling
+   * {@link javax.swing.text.html.HTMLEditorKit#getParser() }.
+   * @param a_dtd a DTD to use.
+   */
+  public DocumentParser(DTD a_dtd)
+  {
+    super(a_dtd);
+    gnu = new gnuParser(a_dtd);
+  }
+
+  /**
+   * Parses the HTML document, calling methods of the provided
+   * callback. This method must be multithread - safe.
+   * @param reader The reader to read the HTML document from
+   * @param callback The callback that is notifyed about the presence
+   * of HTML elements in the document.
+   * @param ignoreCharSet If thrue, any charset changes during parsing
+   * are ignored.
+   * @throws java.io.IOException
+   */
+  public void parse(Reader reader, HTMLEditorKit.ParserCallback a_callback,
+                    boolean ignoreCharSet
+                   )
+             throws IOException
+  {
+    callBack = a_callback;
+    gnu.parse(reader);
+
+    callBack.handleEndOfLineString(gnu.getEndOfLineSequence());
+    try
+      {
+        callBack.flush();
+      }
+    catch (BadLocationException ex)
+      {
+        // Convert this into the supported type of exception.
+        throw new IOException(ex.getMessage());
+      }
+  }
+
+  /**
+   * Handle HTML comment. The default method returns without action.
+   * @param comment the comment being handled
+   */
+  protected void handleComment(char[] comment)
+  {
+  }
+
+  /**
+   * Handle the tag with no content, like &lt;br&gt;. The method is
+   * called for the elements that, in accordance with the current DTD,
+   * has an empty content.
+   * @param tag the tag being handled.
+   * @throws javax.swing.text.ChangedCharSetException
+   */
+  protected void handleEmptyTag(TagElement tag)
+                         throws javax.swing.text.ChangedCharSetException
+  {
+  }
+
+  /**
+   * The method is called when the HTML closing tag ((like &lt;/table&gt;)
+   * is found or if the parser concludes that the one should be present
+   * in the current position.
+   * @param The tag being handled
+   */
+  protected void handleEndTag(TagElement tag)
+  {
+  }
+
+  /* Handle error that has occured in the given line. */
+  protected void handleError(int line, String message)
+  {
+  }
+
+  /**
+   * The method is called when the HTML opening tag ((like &lt;table&gt;)
+   * is found or if the parser concludes that the one should be present
+   * in the current position.
+   * @param The tag being handled
+   */
+  protected void handleStartTag(TagElement tag)
+  {
+  }
+
+  /**
+   * Handle the text section.
+   * @param text a section text.
+   */
+  protected void handleText(char[] text)
+  {
+  }
+}