package org.apache.torque.engine.database.transform;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  import java.io.BufferedInputStream;
  import java.io.BufferedReader;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileReader;
  import java.io.IOException;
  import java.io.Reader;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.xml.parsers.SAXParser;
  import javax.xml.parsers.SAXParserFactory;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.torque.engine.database.model.Column;
  import org.apache.torque.engine.database.model.Database;
  import org.apache.torque.engine.database.model.Table;
  import org.xml.sax.Attributes;
  import org.xml.sax.EntityResolver;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  import org.xml.sax.helpers.DefaultHandler;
  
  /**
   * A Class that is used to parse an input xml schema file and creates and AppData java structure.
   * 
   * @author <a href="mailto:leon@opticode.co.za">Leon Messerschmidt</a>
   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
   * @author <a href="mailto:mpoeschl@marmot.at">Martin Poeschl</a>
   * @author <a href="mailto:fedor.karpelevitch@home.com">Fedor Karpelevitch</a>
   * @version $Id: XmlToData.java,v 1.1 2007-10-21 07:57:26 abyrne Exp $
   */
  public class XmlToData extends DefaultHandler implements EntityResolver {
  	/** Logging class from commons.logging */
  	private static Log log = LogFactory.getLog(XmlToData.class);
  	private Database database;
  	private List<Object> data;
  	private File dtdFile;
  
  	private static SAXParserFactory saxFactory;
  
  	static {
  		saxFactory = SAXParserFactory.newInstance();
  		saxFactory.setValidating(true);
  	}
  
  	/**
  	 * Default custructor
  	 */
  	public XmlToData(Database database, String dtdFilePath) throws MalformedURLException, IOException {
  		this.database = database;
  		this.dtdFile = new File(dtdFilePath);
  	}
  
  	/**
       *
       */
  	public List<?> parseFile(String xmlFile) throws Exception {
  		data = new ArrayList<Object>();
  
  		SAXParser parser = saxFactory.newSAXParser();
  
  		Reader r = new BufferedReader(new FileReader(xmlFile));
  		try {
  			InputSource is = new InputSource(r);
  			is.setSystemId(dtdFile.getAbsolutePath());
  			parser.parse(is, this);
  		} finally {
  			r.close();
  		}
  		return data;
  	}
  
  	/**
 	 * Handles opening elements of the xml file.
 	 */
 	public void startElement(String uri, String localName, String rawName, Attributes attributes) throws SAXException {
 		try {
 			if (rawName.equals("dataset")) {
 				// ignore <dataset> for now.
 			} else {
 				Table table = database.getTableByJavaName(rawName);
 
 				if (table == null) {
 					throw new SAXException("Table '" + rawName + "' unknown");
 				}
 				List<ColumnValue> columnValues = new ArrayList<ColumnValue>();
 				for (int i = 0; i < attributes.getLength(); i++) {
 					Column col = table.getColumnByJavaName(attributes.getQName(i));
 
 					if (col == null) {
 						throw new SAXException("Column " + attributes.getQName(i) + " in table " + rawName + " unknown.");
 					}
 
 					String value = attributes.getValue(i);
 					columnValues.add(new ColumnValue(col, value));
 				}
 				data.add(new DataRow(table, columnValues));
 			}
 		} catch (Exception e) {
 			throw new SAXException(e);
 		}
 	}
 
 	/**
 	 * called by the XML parser
 	 * 
 	 * @return an InputSource for the database.dtd file
 	 */
 	public InputSource resolveEntity(String publicId, String systemId) throws SAXException {
 		try {
 			File systemIdFile = new File(systemId);
 			if (dtdFile.equals(systemIdFile)) {
 				log.debug("Resolver: -> used " + dtdFile.getPath());
 				return new InputSource(new BufferedInputStream(new FileInputStream(dtdFile)));
 			} else {
 				log.debug("Resolver: -> used " + systemId);
 				return getInputSource(systemId);
 			}
 		} catch (IOException e) {
 			throw new SAXException(e);
 		}
 	}
 
 	/**
 	 * get an InputSource for an URL String
 	 * 
 	 * @param urlString
 	 * @return an InputSource for the URL String
 	 */
 	public InputSource getInputSource(String urlString) throws IOException {
 		URL url = new URL(urlString);
 		InputSource src = new InputSource(url.openStream());
 		return src;
 	}
 
 	/**
      *
      */
 	public class DataRow {
 		private Table table;
 		private List<ColumnValue> columnValues;
 
 		public DataRow(Table table, List<ColumnValue> columnValues) {
 			this.table = table;
 			this.columnValues = columnValues;
 		}
 
 		public Table getTable() {
 			return table;
 		}
 
 		public List<?> getColumnValues() {
 			return columnValues;
 		}
 	}
 
 	/**
      *
      */
 	public class ColumnValue {
 		private Column col;
 		private String val;
 
 		public ColumnValue(Column col, String val) {
 			this.col = col;
 			this.val = val;
 		}
 
 		public Column getColumn() {
 			return col;
 		}
 
 		public String getValue() {
 			return val;
 		}
 
 		public String getEscapedValue() {
 			StringBuffer sb = new StringBuffer();
 			sb.append("'");
 			sb.append(StringUtils.replace(val, "'", "''"));
 			sb.append("'");
 			return sb.toString();
 		}
 	}
 }