/* 

  * This file is part of Mosquito meta-loader.

  *

  * Mosquito meta-loader is free software; you can redistribute it and/or modify

  * it under the terms of the GNU Lesser General Public License as published by

  * the Free Software Foundation; either version 3 of the License, or

  * (at your option) any later version.

  *

  * Mosquito meta-loader 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 Lesser General Public License for more details.

  *

  * You should have received a copy of the GNU Lesser General Public License

  * along with this program.  If not, see <http://www.gnu.org/licenses/>.

  * 

  */

 package rs.mgifos.mosquito.impl.pdm;

 import java.io.InputStream;

 import java.util.Hashtable;

 import javax.xml.parsers.SAXParser;

 import javax.xml.parsers.SAXParserFactory;

 import org.apache.log4j.Logger;

 import org.xml.sax.Attributes;

 import org.xml.sax.SAXException;

 import org.xml.sax.helpers.DefaultHandler;

 /**

  * Java class name resolver. Mapping is described within the XML file

  * jclass_resolver.xml.

  * 

  * @author <a href="mailto:nikola.petkov@gmail.com">Nikola Petkov

  *         &lt;nikola.petkov@gmail.com&gt;</a>

  */

 public class JClassResolver {

         private Logger logger = Logger.getLogger(this.getClass());

         class SaxHandler extends DefaultHandler {

                 private static final String PDM_TYPE = "PDMType";

                 private static final String PREC = "Prec";

                 private static final String LEN = "Len";

                 private PDMType actualPDMType = null;

                 public void startElement(String aUri, String aLocalName, String aQName,

                                 Attributes attributes) throws SAXException {

                         try {

                                 if (PDM_TYPE.equals(aQName)) {

                                         String name = attributes.getValue("name");

                                         String jDefaultClass = attributes.getValue("jDefaultClass");

                                         actualPDMType = new PDMType(name, jDefaultClass);

                                         ht.put(name, actualPDMType);

                                 } else if (PREC.equals(aQName)) {

                                         String length = attributes.getValue("length");

                                         String jClass = attributes.getValue("jClass");

                                         PrecType pt = new PrecType(Integer.parseInt(length), jClass);

                                         actualPDMType.addPrec(pt);

                                 } else if (LEN.equals(aQName)) {

                                         String length = attributes.getValue("length");

                                         String jClass = attributes.getValue("jClass");

                                         LenType lt = new LenType(Integer.parseInt(length), jClass);

                                         actualPDMType.addLen(lt);

                                 }

                         } catch (Exception e) {

                                 logger.error("Sax Parsing xml failed!");

                         }

                 }

         }

         private static JClassResolver INSTANCE = null;

         /**

          * Returns singleton's instance

          * 

          * @return singleton's instance

          */

         public static JClassResolver getInstance() {

                 if (INSTANCE == null)

                         INSTANCE = new JClassResolver();

                 return INSTANCE;

         }

         private Hashtable<String, PDMType> ht = new Hashtable<String, PDMType>();

         private JClassResolver() {

                 super();

                 this.init();

         }

         /**

          * @param aType

          * @param aLength

          * @param aPrecision

          * @return Java class name for the specified input type (one of the T_XXX)

          */

         public String getJClassName(String aType, int aLength, int aPrecision) {

                 String retVal = "java.lang.String";

                 try {

                         retVal = ((PDMType) ht.get(aType))

                                         .getClassName(aLength, aPrecision);

                 } catch (Exception e) {

                         logger.warn("Can't resolve type: '" + aType + "'. Check the existence of this type in jclass_resolver.xml file! Default JClass is java.lang.String!");

                         retVal = "java.lang.String";

                 }

                 return retVal;

         }

         private void init() {

                 try {

                         InputStream is = JClassResolver.class

                                         .getResourceAsStream("jclass_resolver.xml");

                         SAXParserFactory factory = SAXParserFactory.newInstance();

                         SAXParser saxParser = factory.newSAXParser();

                         saxParser.parse(is, new SaxHandler());

                 } catch (Exception e) {

                         logger.error("Can't init resolver! Cause: " + e.getMessage());

                 }

         }

 }