ItemParser.java

package eu.choreos.vv.clientgenerator;

import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Stack;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.apache.xerces.impl.Constants;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.ext.DefaultHandler2;

import eu.choreos.vv.exceptions.ParserException;


/**
 * Utility class to parse the Soap XML response of a Web Service operation
 * 
 * @author Leonardo Leite, Guilherme Nogueira
 *
 */
public class ItemParser {

	private static SAXParserFactory parserFactory = SAXParserFactory.newInstance();
	private SAXParser parser;
	private ItemImpl result;

	private class ResponseParserHandler extends DefaultHandler2 {
		private Stack<ItemImpl> tagStack = new Stack<ItemImpl>();

		/**
		 * @param ch     - The characters.
		 * @param start  - The start position in the character array.
		 * @param length - The number of characters to use from the character array.
		 */
		@Override
		public void characters(char[] ch, int start, int lenght) 
		throws SAXException {

			String trimmed = new String(ch, start, lenght).trim();

			if (!trimmed.isEmpty() && !tagStack.empty()) {
				tagStack.peek().appendContent(trimmed);
			}
		}

		/**
		 * @param uri       - The Namespace URI.
		 * @param localName - The local name (without prefix).
		 * @param qName     - The qualified name (with prefix).
		 */
		@Override
		public void endElement(String uri, String localName, String qName)
		throws SAXException {

			if (!tagStack.empty()) {
				ItemImpl poped = tagStack.pop();
				if (!tagStack.empty()){
					ItemImpl father = tagStack.peek();
					father.addChild(poped);
				} else {
					result = poped;
				}
			}

		}

		/**
		 *	@param uri        - The Namespace URI.
		 *	@param localName  - The local name (without prefix).
		 *	@param qName      - The qualified name (with prefix).
		 *	@param attributes - The attributes attached to the element.
		 */
		@Override
		public void startElement(String uri, String localName, String qName, Attributes attributes) 
		throws SAXException {

			String name = getNameWithoutNamespace(qName);

			if (doNotContainsHeaderInformation(name) || !tagStack.empty()) {
				HashMap<String, String> parameters = new HashMap<String, String>();

				for(int i=0; i< attributes.getLength(); i++)
					parameters.put(attributes.getQName(i), attributes.getValue(i));

				result = new ItemImpl(name, parameters);
				tagStack.push(result);
			}
		}

		@Override
		public void startCDATA() throws SAXException {
			if (!tagStack.empty()) {
				tagStack.peek().setContentCDATA(true);
			}
		}

		private boolean doNotContainsHeaderInformation(String name) {
			return !name.contains("Envelope")&&!name.contains("Header")&&!name.contains("Body");
		}

		private String getNameWithoutNamespace(String qName) {
			String[] names = qName.split(":");                        

			return names[names.length  - 1];
		}
	}

	/** Property id: lexical handler. */
	protected static final String LEXICAL_HANDLER =
		Constants.SAX_PROPERTY_PREFIX + Constants.LEXICAL_HANDLER_PROPERTY;

	public Item parse(String xml) throws ParserException {
		try {
			if  (xml == null)
				return null;
			
			InputStream is = new ByteArrayInputStream(xml.getBytes("UTF-8"));
			ResponseParserHandler handler = new ResponseParserHandler();
			parser = parserFactory.newSAXParser();
			parser.setProperty(LEXICAL_HANDLER, handler);
			parser.parse(is, handler);
		} catch (Exception e) {
			throw new ParserException(e);
		}

		return result;
	}

}