Package org.apache.crimson.tree

Source Code of org.apache.crimson.tree.XmlDocumentBuilder

/*
* $Id: XmlDocumentBuilder.java,v 1.6 2001/09/14 00:50:25 edwingo Exp $
*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 2000 The Apache Software Foundation.  All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in
*    the documentation and/or other materials provided with the
*    distribution.
*
* 3. The end-user documentation included with the redistribution,
*    if any, must include the following acknowledgment: 
*       "This product includes software developed by the
*        Apache Software Foundation (http://www.apache.org/)."
*    Alternately, this acknowledgment may appear in the software itself,
*    if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Crimson" and "Apache Software Foundation" must
*    not be used to endorse or promote products derived from this
*    software without prior written permission. For written
*    permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
*    nor may "Apache" appear in their name, without prior written
*    permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Sun Microsystems, Inc.,
* http://www.sun.com.  For more information on the Apache Software
* Foundation, please see <http://www.apache.org/>.
*/

package org.apache.crimson.tree;


import java.io.IOException;

import java.net.URL;

import java.util.Dictionary;
import java.util.Hashtable;
import java.util.Locale;
import java.util.Vector;

import org.w3c.dom.CDATASection;
import org.w3c.dom.Comment;
import org.w3c.dom.Document;
import org.w3c.dom.EntityReference;
import org.w3c.dom.DOMException;
import org.w3c.dom.DOMImplementation;

import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.ContentHandler;
import org.xml.sax.DTDHandler;
import org.xml.sax.Attributes;
import org.xml.sax.ext.LexicalHandler;
import org.xml.sax.ext.DeclHandler;

import org.apache.crimson.parser.AttributesEx;


/**
* This class is a SAX2 ContentHandler which converts a stream of parse
* events into an in-memory DOM document.  After each <em>Parser.parse()</em>
* invocation returns, a resulting DOM Document may be accessed via the
* <em>getDocument</em> method.  The parser and its builder should be used
* together; the builder may be used with only one parser at a time.
*
* <P> This builder optionally does XML namespace processing, reporting
* conformance problems as recoverable errors using the parser's error
* handler. 
*
* <P> Note: element factories are deprecated because they are non-standard
* and are provided here only for backwards compatibility.  To customize
* the document, a powerful technique involves using an element factory
* specifying what element tags (from a given XML namespace) correspond to
* what implementation classes.  Parse trees produced by such a builder can
* have nodes which add behaviors to achieve application-specific
* functionality, such as modifing the tree as it is parsed.
*
* <P> The object model here is that XML elements are polymorphic, with
* semantic intelligence embedded through customized internal nodes.
* Those nodes are created as the parse tree is built.  Such trees now
* build on the W3C Document Object Model (DOM), and other models may be
* supported by the customized nodes.  This allows both generic tools
* (understanding generic interfaces such as the DOM core) and specialized
* tools (supporting specialized behaviors, such as the HTML extensions
* to the DOM core; or for XSL elements) to share data structures.
*
* <P> Normally only "model" semantics are in document data structures,
* but "view" or "controller" semantics can be supported if desired.
*
* <P> Elements may choose to intercept certain parsing events directly.
* They do this by overriding the default implementations of methods
* in the <em>XmlReadable</em> interface.  This is normally done to make
* the DOM tree represent application level modeling requirements, rather
* than matching an XML structure that may not be optimized appropriately.
*
* @author David Brownell
* @version $Revision: 1.6 $
*/
public class XmlDocumentBuilder implements ContentHandler, LexicalHandler,
    DeclHandler, DTDHandler
{
    // used during parsing
    protected XmlDocument    document;
    protected Locator    locator;
    private Locale    locale = Locale.getDefault ();

    private ElementFactory  factory;
    private Vector    attrTmp = new Vector ();
   
    protected ParentNode        elementStack[];
    protected int           topOfStack;
    private boolean    inDTD;
    private boolean    inCDataSection;

    private Doctype    doctype;

    // parser modes
    private boolean    disableNamespaces = true; /* Keep this for
                                                             backward API
                                                             compatibility,
                                                             but it does
                                                             not change any
                                                             behavior. */
    private boolean             ignoreWhitespace = false;
    private boolean             expandEntityRefs = true;
    private boolean             ignoreComments = false;
    private boolean             putCDATAIntoText = false;

   
    /**
     * Default constructor is for use in conjunction with a SAX2 parser.
     */
    public XmlDocumentBuilder() {
        // No-op
    }

   
    /**
     * Returns true if certain lexical information is automatically
     * discarded when a DOM tree is built, producing smaller parse trees
     * that are easier to use.
     * <b>Obsolete:</b> for backwards compatibility
     */
    public boolean isIgnoringLexicalInfo () {
  return ignoreWhitespace && expandEntityRefs
                && ignoreComments && putCDATAIntoText;
    }

    /**
     * Controls whether certain lexical information is discarded.
     *
     * <P> That information includes whitespace in element content which
     * is ignorable (note that some nonvalidating XML parsers will not
     * report that information); all comments; which text is found in
     * CDATA sections; and boundaries of entity references.
     *
     * <P> "Ignorable whitespace" as reported by parsers is whitespace
     * used to format XML markup.  That is, all whitespace except that in
     * "mixed" or ANY content models is ignorable.  When it is discarded,
     * pretty-printing may be necessary to make the document be readable
     * again by humans.
     *
     * <P> Whitespace inside "mixed" and ANY content models needs different
     * treatment, since it could be part of the document content.  In such
     * cases XML defines a <em>xml:space</em> attribute which applications
     * should use to determine whether whitespace must be preserved (value
     * of the attribute is <em>preserve</em>) or whether default behavior
     * (such as eliminating leading and trailing space, and normalizing
     * consecutive internal whitespace to a single space) is allowed.
     *
     * @param value true indicates that such lexical information should
     *  be discarded during parsing.
     * <b>Obsolete:</b> for backwards compatibility
     */
    public void setIgnoringLexicalInfo (boolean value) {
        ignoreWhitespace = value;
        expandEntityRefs = value;
        ignoreComments = value;
        putCDATAIntoText = value;
    }

    /**
     * Internal API used by JAXP implementation.  Access is set to "public"
     * to enable inter-package access.  Use JAXP DocumentBuilderFactory
     * class to access this functionality.
     */
    public void setIgnoreWhitespace(boolean value) {
        ignoreWhitespace = value;
    }

    /**
     * Internal API used by JAXP implementation.  Access is set to "public"
     * to enable inter-package access.  Use JAXP DocumentBuilderFactory
     * class to access this functionality.
     */
    public void setExpandEntityReferences(boolean value) {
        expandEntityRefs = value;
    }

    /**
     * Internal API used by JAXP implementation.  Access is set to "public"
     * to enable inter-package access.  Use JAXP DocumentBuilderFactory
     * class to access this functionality.
     */
    public void setIgnoreComments(boolean value) {
        ignoreComments = value;
    }

    /**
     * Internal API used by JAXP implementation.  Access is set to "public"
     * to enable inter-package access.  Use JAXP DocumentBuilderFactory
     * class to access this functionality.
     */
    public void setPutCDATAIntoText(boolean value) {
        putCDATAIntoText = value;
    }


    /**
     * Returns true if namespace conformance is not checked as the
     * DOM tree is built.
     */
    public boolean getDisableNamespaces () {
  return disableNamespaces;
    }

    /**
     * Controls whether namespace conformance is checked during DOM
     * tree construction, or (the default) not.  In this framework, the
     * DOM Builder is responsible for enforcing all namespace constraints.
     * When enabled, this makes constructing a DOM tree slightly slower.
     * (However, at this time it can't enforce the requirement that
     * parameter entity names not contain colons.)
     */
    public void setDisableNamespaces (boolean value) {
  disableNamespaces = value;
    }

    /**
     * Return the result of parsing, after a SAX parser has used this as a
     * content handler during parsing.
     */
    public XmlDocument getDocument() {
        return document;
    }
   

    /**
     * Returns the locale to be used for diagnostic messages by
     * this builder, and by documents it produces.  This uses
     * the locale of any associated parser.
     */
    public Locale getLocale() {
        return locale;
    }
   
    /**
     * Assigns the locale to be used for diagnostic messages.
     * Multi-language applications, such as web servers dealing with
     * clients from different locales, need the ability to interact
     * with clients in languages other than the server's default.
     *
     * <P>When an XmlDocument is created, its locale is the default
     * locale for the virtual machine.  If a parser was recorded,
     * the locale will be associated with that parser.
     *
     * @see #chooseLocale
     */
    public void  setLocale(Locale locale)
        throws SAXException
    {
  if (locale == null) {
      locale = Locale.getDefault();
        }
  this.locale = locale;
    }

    /**
     * Chooses a client locale to use for diagnostics, using the first
     * language specified in the list that is supported by this builder.
     * That locale is then automatically assigned using <a
     * href="#setLocale(java.util.Locale)">setLocale()</a>.  Such a list
     * could be provided by a variety of user preference mechanisms,
     * including the HTTP <em>Accept-Language</em> header field.
     *
     * @see org.apache.crimson.util.MessageCatalog
     *
     * @param languages Array of language specifiers, ordered with the most
     *  preferable one at the front.  For example, "en-ca" then "fr-ca",
     *  followed by "zh_CN".  Both RFC 1766 and Java styles are supported.
     * @return The chosen locale, or null.
     */
    public Locale chooseLocale (String languages [])
    throws SAXException
    {
  Locale  l = XmlDocument.catalog.chooseLocale (languages);

  if (l != null)
      setLocale (l);
  return l;
    }

    /*
     * Gets the messages from the resource bundles for the given messageId.
     */
    String getMessage (String messageId) {
     return getMessage (messageId, null);
    }

    /*
     * Gets the messages from the resource bundles for the given messageId
     * after formatting it with the parameters passed to it.
     */
    String getMessage (String messageId, Object[] parameters) {
     if (locale == null) {
    getLocale ();
  }
  return XmlDocument.catalog.getMessage (locale, messageId, parameters);
    }

   
    //////////////////////////////////////////////////////////////////////
    // ContentHandler callbacks
    //////////////////////////////////////////////////////////////////////

    /**
     * Receive an object for locating the origin of SAX document events.
     */
    public void setDocumentLocator(Locator locator) {
  this.locator = locator;
    }

    /**
     * This is a factory method, used to create an XmlDocument.
     * Subclasses may override this method, for example to provide
     * document classes with particular behaviors, or provide
     * particular factory behaviours (such as returning elements
     * that support the HTML DOM methods, if they have the right
     * name and are in the right namespace).
     */
    public XmlDocument createDocument ()
    {
  XmlDocument retval = new XmlDocument ();

  if (factory != null) {
            retval.setElementFactory(factory);
        }
  return retval;
    }


    /**
     * Assigns the factory to be associated with documents produced
     * by this builder.
     * @deprecated
     */
    final public void setElementFactory(ElementFactory factory)  {
        this.factory = factory;
    }


    /**
     * Returns the factory to be associated with documents produced
     * by this builder.
     * @deprecated
     */
    final public ElementFactory getElementFactory() {
        return factory;
    }


    /**
     * Receive notification of the beginning of a document.
     */
    public void startDocument () throws SAXException
    {
  document = createDocument ();

  if (locator != null)
      document.setSystemId (locator.getSystemId ());

  //
        // XXX don't want fixed size limits!  Fix someday.  For
  // now, wide trees predominate, not deep ones.  This is
  // allowing a _very_ deep tree ... we typically observe
  // depths on the order of a dozen.
  //
        elementStack = new ParentNode [200];
        topOfStack = 0;
        elementStack [topOfStack] = document;

  inDTD = false;
    }

    /**
     * Receive notification of the end of a document.
     */
    public void endDocument () throws SAXException
    {
        if (topOfStack != 0)
            throw new IllegalStateException (getMessage ("XDB-000"));
  document.trimToSize ();
    }
   
    /**
     * Begin the scope of a prefix-URI Namespace mapping.
     */
    public void startPrefixMapping(String prefix, String uri)
  throws SAXException
    {
        // No-op
    }

    /**
     * End the scope of a prefix-URI mapping.
     */
    public void endPrefixMapping(String prefixthrows SAXException {
        // No-op
    }

    /**
     * Receive notification of the beginning of an element.
     */
    public void startElement(String namespaceURI, String localName,
                             String qName, Attributes attributes)
  throws SAXException
    {
  //
  // Convert set of attributes to DOM representation.
  //
        AttributeSet attSet = null;
  int length = attributes.getLength();
  if (length != 0) {
      try {
                attSet = AttributeSet.createAttributeSet1(attributes);
      } catch (DOMException ex) {
    throw new SAXParseException(getMessage("XDB-002",
                        new Object[] { ex.getMessage() }), locator, ex);
      }
  }

  //
  // Then create the element, associate its attributes, and
  // stack it for later addition.
  //
        ElementNode e = null;
  try {
            e = (ElementNode) document.createElementEx(qName);
  } catch (DOMException ex) {
      throw new SAXParseException(getMessage("XDB-004",
                    new Object[] { ex.getMessage() }), locator, ex);
  }
  if (attributes instanceof AttributesEx) {
      e.setIdAttributeName(
    ((AttributesEx)attributes).getIdAttributeName());
        }
  if (length != 0) {
      e.setAttributes(attSet);
        }

  elementStack[topOfStack++].appendChild(e);
  elementStack[topOfStack] = e;
    }

    /**
     * Receive notification of the end of an element.
     */
    public void endElement(String namespaceURI, String localName,
                           String qName)
  throws SAXException
    {
        ParentNode e = (ParentNode) elementStack[topOfStack];

        elementStack[topOfStack--] = null;

  // Trusting that the SAX parser is correct, and hasn't
  // mismatched start/end element callbacks.
        // if (!tag.equals (e.getTagName ()))
        //     throw new SAXParseException ((getMessage ("XDB-009", new
  //         Object[] { tag, e.getTagName ()  })), locator);

        e.reduceWaste()// use less space
    }

    /**
     * Receive notification of character data.
     */
    public void characters(char buf [], int offset, int len)
        throws SAXException
    {
        ParentNode  top = elementStack [topOfStack];

  if (inCDataSection) {
      String    temp = new String (buf, offset, len);
      CDATASection  section;

      section = (CDATASection) top.getLastChild ();
      section.appendData (temp);
      return;
  }

       
  try {
      NodeBase lastChild = (NodeBase) top.getLastChild ();
      if (lastChild != null && lastChild.getClass() == TextNode.class) {
                // Merge only TextNode data and not CDataNode data
    String tmp  = new String (buf, offset, len);
       ((TextNode)lastChild).appendData (tmp);
      } else {
          TextNode text = document.newText (buf, offset, len);
          top.appendChild (text);
      }
  } catch (DOMException ex) {
      throw new SAXParseException(getMessage("XDB-004",
                    new Object[] { ex.getMessage() }), locator, ex);
  }
    }
   
    /**
     * Receive notification of ignorable whitespace in element content.
     *
     * Reports ignorable whitespace; if lexical information is not ignored
     * the whitespace reported here is recorded in a DOM text (or CDATA, as
     * appropriate) node.
     *
     * @param buf holds text characters
     * @param offset initial index of characters in <em>buf</em>
     * @param len how many characters are being passed
     * @exception SAXException as appropriate
     */
    public void ignorableWhitespace(char buf [], int offset, int len)
        throws SAXException
    {
  if (ignoreWhitespace)
      return;

        characters(buf, offset, len);
    }
   
    /**
     * Receive notification of a processing instruction.
     */
    public void processingInstruction(String name, String instruction)
        throws SAXException
    {
  // Ignore PIs in DTD for DOM support
  if (inDTD)
      return;

        ParentNode  top = elementStack [topOfStack];
        PINode    pi;
 
  try {
      pi = (PINode) document.createProcessingInstruction (name,
        instruction);
      top.appendChild (pi);
  } catch (DOMException ex) {
      throw new SAXParseException(getMessage("XDB-004",
                    new Object[] { ex.getMessage() }), locator, ex);
  }
    }

    /**
     * Receive notification of a skipped entity.
     */
    public void skippedEntity(String name) throws SAXException {
        // No-op
    }


    //////////////////////////////////////////////////////////////////////
    // org.xml.sax.ext.LexicalHandler callbacks
    //////////////////////////////////////////////////////////////////////

    /**
     * Report the start of DTD declarations, if any.
     */
    public void startDTD(String name, String publicId, String systemId)
  throws SAXException
    {
        DOMImplementation impl = document.getImplementation();
        doctype = (Doctype)impl.createDocumentType(name, publicId, systemId);

        // Set the owner since DOM2 specifies this to be null
        doctype.setOwnerDocument(document);

        inDTD = true;
    }

    /**
     * Report the end of DTD declarations.
     */
    public void endDTD() throws SAXException {
        document.appendChild(doctype);
        inDTD = false;
    }

    /**
     * Report the beginning of an entity in content.
     */
    public void startEntity(String name) throws SAXException {
      // Our parser doesn't report Paramater entities. Need to make
  // changes for that.

        // Ignore entity refs while parsing DTD
  if (expandEntityRefs || inDTD) {
      return;
        }

        EntityReference  e = document.createEntityReference(name);
  elementStack[topOfStack++].appendChild(e);
  elementStack[topOfStack] = (ParentNode)e;
    }

    /**
     * Report the end of an entity.
     */
    public void endEntity(String name) throws SAXException {
        // Ignore entity refs while parsing DTD
  if (inDTD) {
            return;
        }

        ParentNode entity = elementStack[topOfStack];

  if (!(entity instanceof EntityReference))
      return;

  entity.setReadonly(true);
        elementStack[topOfStack--] = null;
        if (!name.equals(entity.getNodeName())) {
            throw new SAXParseException(getMessage("XDB-011",
                    new Object[] { name, entity.getNodeName() }), locator);
  }
    }

    /**
     * Report the start of a CDATA section.
     *
     * <P>If this builder is set to record lexical information then this
     * callback arranges that character data (and ignorable whitespace) be
     * recorded as part of a CDATA section, until the matching
     * <em>endCDATA</em> method is called.
     */
    public void startCDATA() throws SAXException {
  if (putCDATAIntoText) {
      return;
        }

        CDATASection text = document.createCDATASection("");
        ParentNode top = elementStack[topOfStack];
       
  try {
      inCDataSection = true;
      top.appendChild(text);
  } catch (DOMException ex) {
      throw new SAXParseException(getMessage("XDB-004",
                    new Object[] { ex.getMessage() }), locator, ex);
  }
    }
   
    /**
     * Report the end of a CDATA section.
     */
    public void endCDATA() throws SAXException {
        inCDataSection = false;
    }
   
    /**
     * Report an XML comment anywhere in the document.
     */
    public void comment(char[] ch, int start, int length) throws SAXException {
  // Ignore comments if lexical info is to be ignored,
  // or if parsing the DTD
  if (ignoreComments || inDTD) {
      return;
        }

        String text = new String(ch, start, length);
        Comment comment = document.createComment(text);
        ParentNode top = elementStack[topOfStack];
       
  try {
      top.appendChild(comment);
  } catch (DOMException ex) {
      throw new SAXParseException(getMessage("XDB-004",
                    new Object[] { ex.getMessage() }), locator, ex);
  }
    }


    //////////////////////////////////////////////////////////////////////
    // org.xml.sax.ext.DeclHandler callbacks
    //////////////////////////////////////////////////////////////////////

    /**
     * Report an element type declaration.
     */
    public void elementDecl(String name, String model) throws SAXException {
        // ignored
    }

    /**
     * Report an attribute type declaration.
     */
    public void attributeDecl(String eName, String aName, String type,
                              String valueDefault, String value)
  throws SAXException
    {
        // ignored
    }

    /**
     * Report an internal entity declaration.
     */
    public void internalEntityDecl(String name, String value)
  throws SAXException
    {
        // SAX2 reports PEDecls which we ignore for DOM2.  SAX2 also reports
        // only the first defined GEDecl which matches with DOM2.
        if (!name.startsWith("%")) {
            doctype.addEntityNode(name, value);
        }
    }

    /**
     * Report a parsed external entity declaration.
     */
    public void externalEntityDecl(String name, String publicId,
                                   String systemId)
  throws SAXException
    {
        // SAX2 reports PEDecls which we ignore for DOM2.  SAX2 also reports
        // only the first defined GEDecl which matches with DOM2.
        if (!name.startsWith("%")) {
            doctype.addEntityNode(name, publicId, systemId, null);
        }
    }


    //////////////////////////////////////////////////////////////////////
    // org.xml.sax.DTDHandler callbacks
    //////////////////////////////////////////////////////////////////////

    /**
     * Receive notification of a notation declaration event.
     */
    public void notationDecl(String n, String p, String s)
  throws SAXException
    {
        doctype.addNotation(n, p, s);
    }

    /**
     * Receive notification of an unparsed entity declaration event.
     */
    public void unparsedEntityDecl(String name, String publicId,
                                   String systemId, String notation)
  throws SAXException
    {
        doctype.addEntityNode(name, publicId, systemId, notation);
    }
}
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