HTMLContentHandler.java

/*
 * CATMA Computer Aided Text Markup and Analysis
 *
 *    Copyright (C) 2008-2010  University Of Hamburg
 *
 *    This program 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 3 of the License, or
 *    (at your option) any later version.
 *
 *    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package de.catma.document.source.contenthandler;

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;

import nu.xom.Builder;
import nu.xom.Document;
import nu.xom.Element;
import nu.xom.Node;
import nu.xom.Text;

import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;

/**
 * A content handler HTML for based {@link de.catma.document.source.SourceDocument}s.
 *
 * @author marco.petris@web.de
 *
 */
public class HTMLContentHandler extends AbstractSourceContentHandler {

	/* (non-Javadoc)
	 * @see de.catma.document.source.contenthandler.SourceContentHandler#load(java.io.InputStream)
	 */
	public void load(InputStream is) throws IOException {
        XMLReader reader;
		try {
			Charset charset = 
					getSourceDocumentInfo().getTechInfoSet().getCharset();
				
			BufferedInputStream bis = null;

            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            bis = new BufferedInputStream(is);
            byte[] byteBuffer = new byte[65536];
            int bCount = -1;
            while ((bCount=bis.read(byteBuffer)) != -1) {
                bos.write(byteBuffer, 0, bCount);
            }

            byte[] byteBuf = bos.toByteArray();
            ByteArrayInputStream toCharBis = new ByteArrayInputStream(byteBuf);

			InputStream fr = null; 
			if (BOMFilterInputStream.hasBOM(byteBuf)) {
				fr = new BOMFilterInputStream( toCharBis, charset );
			}
			else {
				fr = toCharBis;
			}
			
			reader = XMLReaderFactory.createXMLReader("org.ccil.cowan.tagsoup.Parser");
	        Builder builder = new Builder(reader, false, new HTMLFilterFactory());
	        
	        Document document = builder.build(fr);
	        StringBuilder contentBuilder = new StringBuilder();
	        processTextNodes(contentBuilder, document.getRootElement());
	        setContent(contentBuilder.toString());	
		} catch (Exception e) {
			throw new IOException(e);
		}
	}
    
    /* (non-Javadoc)
     * @see de.catma.document.source.contenthandler.SourceContentHandler#load()
     */
    public void load() throws IOException {
        try (InputStream is = getSourceDocumentInfo().getTechInfoSet().getURI().toURL().openStream()) {
       		load(is);
        }
        catch (Exception e) {
        	throw new IOException(e);
        }
    }

    /**
     * Appends text elements to the given builder otherwise descents deeper into the
     * document tree.
     * @param contentBuilder the builder is filled with text elements
     * @param element the current element to process
     */
    private void processTextNodes(StringBuilder contentBuilder, Element element) {
        for( int idx=0; idx<element.getChildCount(); idx++) {
            Node curChild = element.getChild(idx);
            if (curChild instanceof Text) {
                contentBuilder.append(curChild.getValue());
            }
            else if (curChild instanceof Element) { //descent
                processTextNodes(contentBuilder, (Element)curChild);
            }
        }
    }
}