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();

         }

     }

 }