importer.handler.post.annotate.HTMLConverter.java Source code

Introduction

Here is the source code for importer.handler.post.annotate.HTMLConverter.java

Source

/* This file is part of Importer.
 *
 *  Importer 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 of the License, or
 *  (at your option) any later version.
 *
 *  Importer 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 Importer.  If not, see <http://www.gnu.org/licenses/>.
 */
package importer.handler.post.annotate;

import java.util.HashMap;
import java.util.Set;
import java.util.Iterator;
import java.util.Stack;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.parsers.*;
import org.xml.sax.*;
import importer.exception.HTMLException;
import java.io.CharArrayReader;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import java.util.HashSet;

/**
 * Convert standard Harpur XML to HTML
 * @author desmond
 */
public class HTMLConverter extends DefaultHandler {
    StringBuilder body;
    HTMLPattern current;
    JSONArray patterns;
    HashMap<Element, HTMLPattern> map;
    HashSet<String> ignore;
    Stack<HTMLPattern> stack;

    /**
     * Create  a conversion pattern for a particular xml tag
     * @param xmlTag the xml tag name
     * @param htmlTag the corresponding html tag name
     * @param htmlAttrName the html attribute or null
     * @param htmlAttrValue the html attribute value or null
     * @param xmlAttrName the matching xml attribute name or null
     * @param xmlAttrValue the matching xml attribute value or null
     */
    void addPattern(String xmlTag, String htmlTag, String htmlAttrName, String htmlAttrValue, String xmlAttrName,
            String xmlAttrValue) {
        HTMLPattern hp = new HTMLPattern(htmlTag);
        // ignore null html or xml attribute names
        // but values can be null
        if (htmlAttrName != null)
            hp.addAttribute(htmlAttrName, htmlAttrValue);
        // only one matching xml-attribute for now should suffice
        Element elem = new Element(xmlTag);
        if (xmlAttrName != null)
            elem.addAttribute(xmlAttrName, xmlAttrValue);
        map.put(elem, hp);
    }

    /**
     * Convert an xml->html converter with limited functionality
     * @param config the config specifying how to convert the tags+attributes
     */
    HTMLConverter(JSONArray config) {
        this.body = new StringBuilder();
        this.patterns = config;
        map = new HashMap<Element, HTMLPattern>();
        this.stack = new Stack<HTMLPattern>();
        this.ignore = new HashSet<String>();
        for (int i = 0; i < config.size(); i++) {
            JSONObject jObj = (JSONObject) config.get(i);
            String htmlTag = (String) jObj.get("htmlTag");
            String xmlTag = (String) jObj.get("xmlTag");
            String htmlAttrName = (String) jObj.get("htmlAttrName");
            String htmlAttrValue = (String) jObj.get("htmlAttrValue");
            String xmlAttrName = (String) jObj.get("xmlAttrName");
            String xmlAttrValue = (String) jObj.get("xmlAttrValue");
            addPattern(xmlTag, htmlTag, htmlAttrName, htmlAttrValue, xmlAttrName, xmlAttrValue);
        }
    }

    /**
     * Turn XML note content for Harpur to HTML
     * @param xml the xml note
     * @param config the JSON config to control the conversion
     * @return a HTML string
     */
    String convert(String xml) throws HTMLException {
        try {
            SAXParserFactory spf = SAXParserFactory.newInstance();
            HTMLConverter conv = new HTMLConverter(patterns);
            spf.setNamespaceAware(true);
            SAXParser parser = spf.newSAXParser();
            XMLReader xmlReader = parser.getXMLReader();
            xmlReader.setContentHandler(conv);
            xmlReader.setErrorHandler(new MyErrorHandler(System.err));
            CharArrayReader car = new CharArrayReader(xml.toCharArray());
            InputSource input = new InputSource(car);
            xmlReader.parse(input);
            return conv.body.toString();
        } catch (Exception e) {
            throw new HTMLException(e);
        }
    }

    public void startElement(String namespaceURI, String localName, String qName, Attributes atts)
            throws SAXException {
        Set<Element> keys = map.keySet();
        Iterator<Element> iter = keys.iterator();
        Element best = null;
        //System.out.println(localName);
        while (iter.hasNext()) {
            Element e = iter.next();
            if (e.matches(localName, atts)) {
                if (best == null || e.isBetterThan(best))
                    best = e;
            }
        }
        // use longest match
        if (best != null) {
            HTMLPattern hp = map.get(best);
            body.append(hp.getStartTag(atts));
            stack.push(hp);
            current = hp;
        } else
            ignore.add(localName);
    }

    public void characters(char[] ch, int start, int length) {
        body.append(ch, start, length);
    }

    public void endElement(String uri, String localName, String qName) {
        if (current != null) {
            body.append(current.getEndTag());
            if (!ignore.contains(localName))
                current = stack.pop();
        }
    }
}