ConfigHandler.java

/*******************************************************************************
 * Copyright (c) 2003-2005, 2013 Till Zoppke.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Public License v3.0
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/gpl.html
 * 
 * Contributors:
 *     Till Zoppke - initial API and implementation
 ******************************************************************************/
/*
 * ConfigurationHandler.java
 * 
 * Created on 10.02.2004
 */
package eniac.data.io;

import java.util.Stack;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;

import eniac.data.model.EData;
import eniac.data.model.EData.Tag;
import eniac.data.model.parent.Configuration;
import eniac.data.model.parent.ParentData;
import eniac.data.type.EType;
import eniac.io.Proxy;
import eniac.log.Log;

/**
 * @author zoppke
 */
public class ConfigHandler extends DefaultHandler {

	// ================================ fields
	// ==================================

	// stack for the data objects to be parsed
	private Stack<EData> _stack = new Stack<>();

	// reference to the configuration as the root of our dataObject tree.
	// if parsing was not successful, this will stay null.
	private Configuration _configuration = null;

	/**
	 * Creates a new configurationHandler
	 */
	public ConfigHandler() {
		// empty constructor
	}

	public Configuration getConfiguration() {
		return _configuration;
	}

	// ===================== overriding DefaultHandler methods
	// ==================

	public void startElement(String uri, String localName, String qName, Attributes attrs) throws SAXException {

		try {
			// read type from string
			EType type = convertToType(qName);
			if (type == null) {
				return;
			}

			// create dataObject and push it to the stack.
			EData data = type.makeEData();
			data.setAttributes(attrs);
			_stack.push(data);
		} catch (Exception e) {
			// in case of exception, print stack trace and rethrow as sax
			e.printStackTrace();
			throw new SAXException(e);
		}
	}

	public void endElement(String uri, String localName, String qName) throws SAXException {

		try {
			// read type from string
			EType type = convertToType(qName);
			if (type == null) {
				return;
			}

			// pop object from stack
			EData data = _stack.pop();
			if (data instanceof Configuration) {
				// special case: assign configuration field
				_configuration = (Configuration) data;
			}
			else {
				// add object as new child to the top-of_stack-dataObject.
				ParentData parent = (ParentData) _stack.peek();
				parent.addChild(data);
			}
		} catch (Exception e) {
			// in case of exception, print stack trace and rethrow as sax
			e.printStackTrace();
			throw new SAXException(e);
		}
	}

	public void warning(SAXParseException e) throws SAXException {
		Log.log(e.toString());
	}

	public void error(SAXParseException e) throws SAXException {
		Log.log(e.toString());
	}

	private EType convertToType(String name) {
		try {
			return Enum.valueOf(EType.class, name.toUpperCase());
		} catch (IllegalArgumentException exc) {

			// check, if this is a proxy tag
			try {
				Enum.valueOf(Proxy.Tag.class, name.toUpperCase());
			} catch (IllegalArgumentException exc2) {

				// we have either the root element "eniac" or an unknown tag
				if (!Tag.ENIAC.name().equalsIgnoreCase(name)) {
					System.out.println("Ignoring unknown type: " + name);
				}
			}
			return null;
		}
	}

}