src/java/org/apache/fop/util/DOM2SAX.java - xmlgraphics-fop - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 /* $Id$ */

 package org.apache.fop.util;

 import java.util.List;
 import java.util.Map;
 import java.util.Stack;

 import org.w3c.dom.Document;
 import org.w3c.dom.NamedNodeMap;
 import org.w3c.dom.Node;
 import org.xml.sax.ContentHandler;
 import org.xml.sax.SAXException;
 import org.xml.sax.ext.LexicalHandler;
 import org.xml.sax.helpers.AttributesImpl;

 /**
  * Helper class that produces a SAX stream from a DOM Document.
  * <p>
  * Part of the code here copied and adapted from Apache Xalan-J,
  * src/org/apache/xalan/xsltc/trax/DOM2SAX.java
  */
 public class DOM2SAX {

     private static final String EMPTYSTRING = "";
     private static final String XMLNS_PREFIX = "xmlns";

     private ContentHandler contentHandler;
     private LexicalHandler lexicalHandler;

     private Map prefixes = new java.util.HashMap();

     /**
      * Main constructor
      * @param handler the ContentHandler to send SAX events to
      */
     public DOM2SAX(ContentHandler handler) {
         this.contentHandler = handler;
         if (handler instanceof LexicalHandler) {
             this.lexicalHandler = (LexicalHandler)handler;
         }
     }

     /**
      * Writes the given document using the given ContentHandler.
      * @param doc DOM document
      * @param fragment if false no startDocument() and endDocument() calls are issued.
      * @throws SAXException In case of a problem while writing XML
      */
     public void writeDocument(Document doc, boolean fragment) throws SAXException {
         if (!fragment) {
             contentHandler.startDocument();
         }
         for (Node n = doc.getFirstChild(); n != null;
                 n = n.getNextSibling()) {
             writeNode(n);
         }
         if (!fragment) {
             contentHandler.endDocument();
         }
     }

     /**
      * Writes the given fragment using the given ContentHandler.
      * @param node DOM node
      * @throws SAXException In case of a problem while writing XML
      */
     public void writeFragment(Node node) throws SAXException {
         writeNode(node);
     }

     /**
      * Begin the scope of namespace prefix. Forward the event to the SAX handler
      * only if the prefix is unknown or it is mapped to a different URI.
      */
     private boolean startPrefixMapping(String prefix, String uri)
             throws SAXException {
         boolean pushed = true;
         Stack uriStack = (Stack)prefixes.get(prefix);

         if (uriStack != null) {
             if (uriStack.isEmpty()) {
                 contentHandler.startPrefixMapping(prefix, uri);
                 uriStack.push(uri);
             } else {
                 final String lastUri = (String) uriStack.peek();
                 if (!lastUri.equals(uri)) {
                     contentHandler.startPrefixMapping(prefix, uri);
                     uriStack.push(uri);
                 } else {
                     pushed = false;
                 }
             }
         } else {
             contentHandler.startPrefixMapping(prefix, uri);
             uriStack = new Stack();
             prefixes.put(prefix, uriStack);
             uriStack.push(uri);
         }
         return pushed;
     }

     /*
      * End the scope of a name prefix by popping it from the stack and passing
      * the event to the SAX Handler.
      */
     private void endPrefixMapping(String prefix) throws SAXException {
         final Stack uriStack = (Stack)prefixes.get(prefix);

         if (uriStack != null) {
             contentHandler.endPrefixMapping(prefix);
             uriStack.pop();
         }
     }

     /**
      * If the DOM was created using a DOM 1.0 API, the local name may be null.
      * If so, get the local name from the qualified name before generating the
      * SAX event.
      */
     private static String getLocalName(Node node) {
         final String localName = node.getLocalName();

         if (localName == null) {
             final String qname = node.getNodeName();
             final int col = qname.lastIndexOf(':');
             return (col > 0) ? qname.substring(col + 1) : qname;
         }
         return localName;
     }

     /**
      * Writes a node using the given writer.
      * @param node node to serialize
      * @throws SAXException In case of a problem while writing XML
      */
     private void writeNode(Node node)
                 throws SAXException {
         if (node == null) {
             return;
         }

         switch (node.getNodeType()) {
         case Node.ATTRIBUTE_NODE: // handled by ELEMENT_NODE
         case Node.DOCUMENT_FRAGMENT_NODE:
         case Node.DOCUMENT_TYPE_NODE:
         case Node.ENTITY_NODE:
         case Node.ENTITY_REFERENCE_NODE:
         case Node.NOTATION_NODE:
             // These node types are ignored!!!
             break;
         case Node.CDATA_SECTION_NODE:
             final String cdata = node.getNodeValue();
             if (lexicalHandler != null) {
                 lexicalHandler.startCDATA();
                 contentHandler.characters(cdata.toCharArray(), 0, cdata.length());
                 lexicalHandler.endCDATA();
             } else {
                 // in the case where there is no lex handler, we still
                 // want the text of the cdate to make its way through.
                 contentHandler.characters(cdata.toCharArray(), 0, cdata.length());
             }
             break;

         case Node.COMMENT_NODE: // should be handled!!!
             if (lexicalHandler != null) {
                 final String value = node.getNodeValue();
                 lexicalHandler.comment(value.toCharArray(), 0, value.length());
             }
             break;
         case Node.DOCUMENT_NODE:
             contentHandler.startDocument();
             Node next = node.getFirstChild();
             while (next != null) {
                 writeNode(next);
                 next = next.getNextSibling();
             }
             contentHandler.endDocument();
             break;

         case Node.ELEMENT_NODE:
             String prefix;
             List pushedPrefixes = new java.util.ArrayList();
             final AttributesImpl attrs = new AttributesImpl();
             final NamedNodeMap map = node.getAttributes();
             final int length = map.getLength();

             // Process all namespace declarations
             for (int i = 0; i < length; i++) {
                 final Node attr = map.item(i);
                 final String qnameAttr = attr.getNodeName();

                 // Ignore everything but NS declarations here
                 if (qnameAttr.startsWith(XMLNS_PREFIX)) {
                     final String uriAttr = attr.getNodeValue();
                     final int colon = qnameAttr.lastIndexOf(':');
                     prefix = (colon > 0) ? qnameAttr.substring(colon + 1)
                             : EMPTYSTRING;
                     if (startPrefixMapping(prefix, uriAttr)) {
                         pushedPrefixes.add(prefix);
                     }
                 }
             }

             // Process all other attributes
             for (int i = 0; i < length; i++) {
                 final Node attr = map.item(i);
                 final String qnameAttr = attr.getNodeName();

                 // Ignore NS declarations here
                 if (!qnameAttr.startsWith(XMLNS_PREFIX)) {
                     final String uriAttr = attr.getNamespaceURI();

                     // Uri may be implicitly declared
                     if (uriAttr != null) {
                         final int colon = qnameAttr.lastIndexOf(':');
                         prefix = (colon > 0) ? qnameAttr.substring(0, colon)
                                 : EMPTYSTRING;
                         if (startPrefixMapping(prefix, uriAttr)) {
                             pushedPrefixes.add(prefix);
                         }
                     }

                     // Add attribute to list
                     attrs.addAttribute(attr.getNamespaceURI(),
                             getLocalName(attr), qnameAttr, XMLUtil.CDATA, attr
                                     .getNodeValue());
                 }
             }

             // Now process the element itself
             final String qname = node.getNodeName();
             final String uri = node.getNamespaceURI();
             final String localName = getLocalName(node);

             // Uri may be implicitly declared
             if (uri != null) {
                 final int colon = qname.lastIndexOf(':');
                 prefix = (colon > 0) ? qname.substring(0, colon) : EMPTYSTRING;
                 if (startPrefixMapping(prefix, uri)) {
                     pushedPrefixes.add(prefix);
                 }
             }

             // Generate SAX event to start element
             contentHandler.startElement(uri, localName, qname, attrs);

             // Traverse all child nodes of the element (if any)
             next = node.getFirstChild();
             while (next != null) {
                 writeNode(next);
                 next = next.getNextSibling();
             }

             // Generate SAX event to close element
             contentHandler.endElement(uri, localName, qname);

             // Generate endPrefixMapping() for all pushed prefixes
             final int nPushedPrefixes = pushedPrefixes.size();
             for (int i = 0; i < nPushedPrefixes; i++) {
                 endPrefixMapping((String)pushedPrefixes.get(i));
             }
             break;

         case Node.PROCESSING_INSTRUCTION_NODE:
             contentHandler.processingInstruction(node.getNodeName(), node.getNodeValue());
             break;

         case Node.TEXT_NODE:
             final String data = node.getNodeValue();
             contentHandler.characters(data.toCharArray(), 0, data.length());
             break;
         default:
             //nop
         }
     }


 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	/* $Id$ */

	package org.apache.fop.util;

	import java.util.List;
	import java.util.Map;
	import java.util.Stack;

	import org.w3c.dom.Document;
	import org.w3c.dom.NamedNodeMap;
	import org.w3c.dom.Node;
	import org.xml.sax.ContentHandler;
	import org.xml.sax.SAXException;
	import org.xml.sax.ext.LexicalHandler;
	import org.xml.sax.helpers.AttributesImpl;

	/**
	* Helper class that produces a SAX stream from a DOM Document.
	* <p>
	* Part of the code here copied and adapted from Apache Xalan-J,
	* src/org/apache/xalan/xsltc/trax/DOM2SAX.java
	*/
	public class DOM2SAX {

	private static final String EMPTYSTRING = "";
	private static final String XMLNS_PREFIX = "xmlns";

	private ContentHandler contentHandler;
	private LexicalHandler lexicalHandler;

	private Map prefixes = new java.util.HashMap();

	/**
	* Main constructor
	* @param handler the ContentHandler to send SAX events to
	*/
	public DOM2SAX(ContentHandler handler) {
	this.contentHandler = handler;
	if (handler instanceof LexicalHandler) {
	this.lexicalHandler = (LexicalHandler)handler;
	}
	}

	/**
	* Writes the given document using the given ContentHandler.
	* @param doc DOM document
	* @param fragment if false no startDocument() and endDocument() calls are issued.
	* @throws SAXException In case of a problem while writing XML
	*/
	public void writeDocument(Document doc, boolean fragment) throws SAXException {
	if (!fragment) {
	contentHandler.startDocument();
	}
	for (Node n = doc.getFirstChild(); n != null;
	n = n.getNextSibling()) {
	writeNode(n);
	}
	if (!fragment) {
	contentHandler.endDocument();
	}
	}

	/**
	* Writes the given fragment using the given ContentHandler.
	* @param node DOM node
	* @throws SAXException In case of a problem while writing XML
	*/
	public void writeFragment(Node node) throws SAXException {
	writeNode(node);
	}

	/**
	* Begin the scope of namespace prefix. Forward the event to the SAX handler
	* only if the prefix is unknown or it is mapped to a different URI.
	*/
	private boolean startPrefixMapping(String prefix, String uri)
	throws SAXException {
	boolean pushed = true;
	Stack uriStack = (Stack)prefixes.get(prefix);

	if (uriStack != null) {
	if (uriStack.isEmpty()) {
	contentHandler.startPrefixMapping(prefix, uri);
	uriStack.push(uri);
	} else {
	final String lastUri = (String) uriStack.peek();
	if (!lastUri.equals(uri)) {
	contentHandler.startPrefixMapping(prefix, uri);
	uriStack.push(uri);
	} else {
	pushed = false;
	}
	}
	} else {
	contentHandler.startPrefixMapping(prefix, uri);
	uriStack = new Stack();
	prefixes.put(prefix, uriStack);
	uriStack.push(uri);
	}
	return pushed;
	}

	/*
	* End the scope of a name prefix by popping it from the stack and passing
	* the event to the SAX Handler.
	*/
	private void endPrefixMapping(String prefix) throws SAXException {
	final Stack uriStack = (Stack)prefixes.get(prefix);

	if (uriStack != null) {
	contentHandler.endPrefixMapping(prefix);
	uriStack.pop();
	}
	}

	/**
	* If the DOM was created using a DOM 1.0 API, the local name may be null.
	* If so, get the local name from the qualified name before generating the
	* SAX event.
	*/
	private static String getLocalName(Node node) {
	final String localName = node.getLocalName();

	if (localName == null) {
	final String qname = node.getNodeName();
	final int col = qname.lastIndexOf(':');
	return (col > 0) ? qname.substring(col + 1) : qname;
	}
	return localName;
	}

	/**
	* Writes a node using the given writer.
	* @param node node to serialize
	* @throws SAXException In case of a problem while writing XML
	*/
	private void writeNode(Node node)
	throws SAXException {
	if (node == null) {
	return;
	}

	switch (node.getNodeType()) {
	case Node.ATTRIBUTE_NODE: // handled by ELEMENT_NODE
	case Node.DOCUMENT_FRAGMENT_NODE:
	case Node.DOCUMENT_TYPE_NODE:
	case Node.ENTITY_NODE:
	case Node.ENTITY_REFERENCE_NODE:
	case Node.NOTATION_NODE:
	// These node types are ignored!!!
	break;
	case Node.CDATA_SECTION_NODE:
	final String cdata = node.getNodeValue();
	if (lexicalHandler != null) {
	lexicalHandler.startCDATA();
	contentHandler.characters(cdata.toCharArray(), 0, cdata.length());
	lexicalHandler.endCDATA();
	} else {
	// in the case where there is no lex handler, we still
	// want the text of the cdate to make its way through.
	contentHandler.characters(cdata.toCharArray(), 0, cdata.length());
	}
	break;

	case Node.COMMENT_NODE: // should be handled!!!
	if (lexicalHandler != null) {
	final String value = node.getNodeValue();
	lexicalHandler.comment(value.toCharArray(), 0, value.length());
	}
	break;
	case Node.DOCUMENT_NODE:
	contentHandler.startDocument();
	Node next = node.getFirstChild();
	while (next != null) {
	writeNode(next);
	next = next.getNextSibling();
	}
	contentHandler.endDocument();
	break;

	case Node.ELEMENT_NODE:
	String prefix;
	List pushedPrefixes = new java.util.ArrayList();
	final AttributesImpl attrs = new AttributesImpl();
	final NamedNodeMap map = node.getAttributes();
	final int length = map.getLength();

	// Process all namespace declarations
	for (int i = 0; i < length; i++) {
	final Node attr = map.item(i);
	final String qnameAttr = attr.getNodeName();

	// Ignore everything but NS declarations here
	if (qnameAttr.startsWith(XMLNS_PREFIX)) {
	final String uriAttr = attr.getNodeValue();
	final int colon = qnameAttr.lastIndexOf(':');
	prefix = (colon > 0) ? qnameAttr.substring(colon + 1)
	: EMPTYSTRING;
	if (startPrefixMapping(prefix, uriAttr)) {
	pushedPrefixes.add(prefix);
	}
	}
	}

	// Process all other attributes
	for (int i = 0; i < length; i++) {
	final Node attr = map.item(i);
	final String qnameAttr = attr.getNodeName();

	// Ignore NS declarations here
	if (!qnameAttr.startsWith(XMLNS_PREFIX)) {
	final String uriAttr = attr.getNamespaceURI();

	// Uri may be implicitly declared
	if (uriAttr != null) {
	final int colon = qnameAttr.lastIndexOf(':');
	prefix = (colon > 0) ? qnameAttr.substring(0, colon)
	: EMPTYSTRING;
	if (startPrefixMapping(prefix, uriAttr)) {
	pushedPrefixes.add(prefix);
	}
	}

	// Add attribute to list
	attrs.addAttribute(attr.getNamespaceURI(),
	getLocalName(attr), qnameAttr, XMLUtil.CDATA, attr
	.getNodeValue());
	}
	}

	// Now process the element itself
	final String qname = node.getNodeName();
	final String uri = node.getNamespaceURI();
	final String localName = getLocalName(node);

	// Uri may be implicitly declared
	if (uri != null) {
	final int colon = qname.lastIndexOf(':');
	prefix = (colon > 0) ? qname.substring(0, colon) : EMPTYSTRING;
	if (startPrefixMapping(prefix, uri)) {
	pushedPrefixes.add(prefix);
	}
	}

	// Generate SAX event to start element
	contentHandler.startElement(uri, localName, qname, attrs);

	// Traverse all child nodes of the element (if any)
	next = node.getFirstChild();
	while (next != null) {
	writeNode(next);
	next = next.getNextSibling();
	}

	// Generate SAX event to close element
	contentHandler.endElement(uri, localName, qname);

	// Generate endPrefixMapping() for all pushed prefixes
	final int nPushedPrefixes = pushedPrefixes.size();
	for (int i = 0; i < nPushedPrefixes; i++) {
	endPrefixMapping((String)pushedPrefixes.get(i));
	}
	break;

	case Node.PROCESSING_INSTRUCTION_NODE:
	contentHandler.processingInstruction(node.getNodeName(), node.getNodeValue());
	break;

	case Node.TEXT_NODE:
	final String data = node.getNodeValue();
	contentHandler.characters(data.toCharArray(), 0, data.length());
	break;
	default:
	//nop
	}
	}


	}