/* Copyright © 2013 Matthew Champion

 All rights reserved.

 Redistribution and use in source and binary forms, with or without

 modification, are permitted provided that the following conditions are met:

  * Redistributions of source code must retain the above copyright

       notice, this list of conditions and the following disclaimer.

  * Redistributions in binary form must reproduce the above copyright

       notice, this list of conditions and the following disclaimer in the

       documentation and/or other materials provided with the distribution.

  * Neither the name of mattunderscore.com nor the

       names of its contributors may be used to endorse or promote products

       derived from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND

 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 DISCLAIMED. IN NO EVENT SHALL MATTHEW CHAMPION BE LIABLE FOR ANY

 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */

 package com.mattunderscore.filter.contentnegotiation.variantsource;

 import java.io.InputStream;

 import java.util.List;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 import javax.xml.parsers.SAXParser;

 import javax.xml.parsers.SAXParserFactory;

 import javax.xml.validation.Schema;

 import com.mattunderscore.filter.contentnegotiation.parser.Variant;

 /**

  * A variant source that parses XML for variants. It uses SAX to parse the XML. The XML is passed in

  * through an input stream. A SAX handler to use can also be passed in. By default it uses the

  * {@link VariantXMLParser} class. This class will try to validate the XML file against the schema.

  * 

  * @author Matt Champion

  * @since 0.2.0

  */

 public class BaseVariantXMLSource implements InputStreamVariantSource

 {

     private static final Logger log = Logger.getLogger(FilterVariantXMLSource.class

             .getCanonicalName());

     private InputStream inputStream;

     private VariantSAXHandler parser;

     public BaseVariantXMLSource()

     {

         this(new VariantXMLParser());

     }

     public BaseVariantXMLSource(final VariantSAXHandler parser)

     {

         this.parser = parser;

     }

     /**

      * Setter for the SAX handler.

      * 

      * @param handler

      *            The SAX handler

      * @since 0.2.0

      */

     public void setHandler(final VariantSAXHandler handler)

     {

         this.parser = handler;

     }

     @Override

     public List<Variant> getVariants() throws VariantSourceException

     {

         if (inputStream == null)

         {

             throw new VariantSourceConfigurationException("No input stream has been set");

         }

         else

         {

             try

             {

                 final SAXParserFactory factory = SAXParserFactory.newInstance();

                 try

                 {

                     final Schema schema = parser.getSchema();

                     if (schema != null)

                     {

                         factory.setValidating(false);

                         factory.setNamespaceAware(true);

                         factory.setSchema(schema);

                     }

                     else

                     {

                         log.log(Level.FINE, "XML Validation not required");

                     }

                 }

                 catch (final NoSchemaException exception)

                 {

                     log.log(Level.FINE, "XML Validation not required");

                 }

                 final SAXParser saxParser = factory.newSAXParser();

                 saxParser.parse(inputStream, parser);

                 return parser.getVariants();

             }

             catch (final Throwable throwable)

             {

                 log.log(Level.WARNING, "BaseVariantXMLSource unable to return variants.",

                         throwable);

                 throw new VariantSourceException("BaseVariantXMLSource unable to return variants.",

                         throwable);

             }

         }

     }

     @Override

     public void setInputStream(final InputStream inputStream)

     {

         this.inputStream = inputStream;

     }

 }