path: root/src/org/apache/fop/fo/FOTreeBuilder.java

/*-- $Id$ -- 

 ============================================================================
                   The Apache Software License, Version 1.1
 ============================================================================
 
    Copyright (C) 1999 The Apache Software Foundation. All rights reserved.
 
 Redistribution and use in source and binary forms, with or without modifica-
 tion, 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 "Fop" 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 (INCLU-
 DING, 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 created by
 James Tauber <jtauber@jtauber.com>. For more  information on the Apache 
 Software Foundation, please see <http://www.apache.org/>.
 
 */
package org.apache.fop.fo;



// FOP

import org.apache.fop.layout.AreaTree;

import org.apache.fop.apps.FOPException;

import org.apache.fop.fo.pagination.Root;



// SAX

import org.xml.sax.HandlerBase;

import org.xml.sax.SAXException;

import org.xml.sax.InputSource;

import org.xml.sax.AttributeList;



// Java

import java.util.Hashtable;

import java.util.Stack;

import java.io.IOException;



/**

 * SAX Handler that builds the formatting object tree.

 */

public class FOTreeBuilder extends HandlerBase {



    /**

     * table mapping element names to the makers of objects

     * representing formatting objects

     */

    protected Hashtable fobjTable = new Hashtable();



    /**

     * class that builds a property list for each formatting object

     */

    protected PropertyListBuilder propertyListBuilder = new

	PropertyListBuilder(); 

	

    /**

     * current formatting object being handled

     */

    protected FObj currentFObj = null;



    /**

     * the root of the formatting object tree

     */

    protected FObj rootFObj = null;



    /**

     * set of names of formatting objects encountered but unknown

     */

    protected Hashtable unknownFOs = new Hashtable();



    // namespace implementation ideas pinched from John Cowan

    protected static class NSMap {

	String prefix;

	String uri;

	int level;



	NSMap(String prefix, String uri, int level) {

	    this.prefix = prefix;

	    this.uri = uri;

	    this.level = level;

	}

    }



    protected int level = 0;

    protected Stack namespaceStack = new Stack();



    {

	namespaceStack.push(new NSMap("xml",

				      "http://www.w3.org/XML/1998/namespace",

				      -1));

	namespaceStack.push(new NSMap("", "", -1));

    }



    protected String findURI(String prefix) {

	for (int i = namespaceStack.size() - 1; i >= 0; i--) {

	    NSMap nsMap = (NSMap) (namespaceStack.elementAt(i));

	    if (prefix.equals(nsMap.prefix)) return nsMap.uri;

	}

	return null;

    }



    protected String mapName(String name)

	throws SAXException {

	int colon = name.indexOf(':');

	String prefix = "";

	String localPart = name;

	if (colon != -1) {

	    prefix = name.substring(0, colon);

	    localPart = name.substring(colon + 1);

	}

	String uri = findURI(prefix);

	if (uri == null) {

	    if (prefix.equals("")) {

		return name;

	    } else {

		throw new SAXException(new FOPException("Unknown namespace prefix " + prefix));

	    }

	}

	return uri + "^" + localPart;

    }



    /**

     * add a mapping from element name to maker.

     *

     * @param namespaceURI namespace URI of formatting object element

     * @param localName local name of formatting object element

     * @param maker Maker for class representing formatting object

    */

    public void addMapping(String namespaceURI, String localName,

			   FObj.Maker maker) {

	this.fobjTable.put(namespaceURI + "^" + localName, maker);

    }



    /** SAX Handler for characters */

    public void characters(char data[], int start, int length) {

	currentFObj.addCharacters(data, start, start + length);

    }



    /** SAX Handler for the end of an element */

    public void endElement(String name) {

	currentFObj.end();

	currentFObj = (FObj) currentFObj.getParent();

	level--;

	while (((NSMap) namespaceStack.peek()).level > level) {

	    namespaceStack.pop();

	}

    }



    /** SAX Handler for the start of the document */

    public void startDocument() {

	System.err.println("building formatting object tree");

    }



    /** SAX Handler for the start of an element */

    public void startElement(String name, AttributeList attlist)

	throws SAXException { 



	/* the formatting object started */

	FObj fobj;



	/* the maker for the formatting object started */

	FObj.Maker fobjMaker;



	level++;

	int length = attlist.getLength();

	for (int i = 0; i < length; i++) {

	    String att = attlist.getName(i);

	    if (att.equals("xmlns")) {

		namespaceStack.push( new NSMap("",

					       attlist.getValue(i),

					       level));

	    } else if (att.startsWith("xmlns:")) {

		String value = attlist.getValue(i);

		namespaceStack.push(new NSMap(att.substring(6), value,

					      level));

	    }

	}

	String fullName = mapName(name);



	fobjMaker = (FObj.Maker) fobjTable.get(fullName);



	if (fobjMaker == null) {

	    if (!this.unknownFOs.containsKey(fullName)) {

		this.unknownFOs.put(fullName, "");

		System.err.println("WARNING: Unknown formatting object "

				   + fullName);  

	    }

	    fobjMaker = new FObjMixed.Maker(); // fall back

	}

	

	try {

	    fobj =

		fobjMaker.make(currentFObj, 

 	       this.propertyListBuilder.makeList(attlist,  

		     (currentFObj == null) ? null : currentFObj.properties));

	} catch (FOPException e) {

	    throw new SAXException(e);

	}



	if (rootFObj == null) {

	    rootFObj = fobj;

	    if (!fobj.getName().equals("fo:root")) {

		throw new SAXException(new FOPException("Root element must"

							+ " be root, not "

							+ fobj.getName())); 

	    }

	} else {

	    currentFObj.addChild(fobj);

	}

	

	currentFObj = fobj;

    }



    /**

     * format this formatting object tree

     *

     * @param areaTree the area tree to format into

     */

    public void format(AreaTree areaTree)

	throws FOPException {

	System.err.println("formatting FOs into areas");

	((Root) this.rootFObj).format(areaTree);

    }

}