/*

  * Copyright 1999,2004 The Apache Software Foundation.

  * 

  * Licensed 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.

  */

 package org.apache.commons.feedparser;

 import java.util.Iterator;

 import java.util.List;

 import org.jaxen.jdom.JDOMXPath;

 import org.jdom.Element;

 /**

  * Handles parsing OPML.

  *

  * @author <a href="mailto:burton@apache.org">Kevin A. Burton (burtonator)</a>

  * @version $Id: OPMLFeedParser.java 373614 2006-01-30 22:31:21Z mvdb $

  */

 public class OPMLFeedParser {

     /**

      * Parse this feed.

      *

      * 

      */

     public static void parse( FeedParserListener listener,

                               org.jdom.Document doc ) throws FeedParserException {

         try {

             FeedParserState state = new FeedParserState();

             //will result in an incorrect interface if the caller isn't using the

             //system correctly.

             FeedVersion v = new FeedVersion();

             v.isOPML = true;

             listener.onFeedVersion( v );

             listener.init();

             FeedDirectoryParserListener fdpl = (FeedDirectoryParserListener)listener;

             //this should be the root directory.

             JDOMXPath xpath = new JDOMXPath( "/opml/body/outline" );

             List list = xpath.selectNodes( doc );

             Iterator i = list.iterator();

             while ( i.hasNext() ) {

                 Element child = (Element)i.next();

                 onOutline( fdpl, state, child );

             }

             listener.finished();

         } catch ( Throwable t ) { throw new FeedParserException( t ); }

     }

     private static void onOutlineFolder( FeedDirectoryParserListener listener,

                                          FeedParserState state,

                                          Element current ) throws Exception {

         JDOMXPath xpath = new JDOMXPath( "outline" );

         List list = xpath.selectNodes( current );

         Iterator i = list.iterator();

         while ( i.hasNext() ) {

             Element child = (Element)i.next();

             onOutline( listener, state, child );

         }

     }

     private static void onOutline( FeedDirectoryParserListener listener,

                                    FeedParserState state,

                                    Element current ) throws Exception {

         String title = current.getAttributeValue( "title" );

         if ( title == null )

             title = current.getAttributeValue( "text" );

         String weblog = current.getAttributeValue( "htmlUrl" );

         String description = current.getAttributeValue( "description" );

         String feed = current.getAttributeValue( "xmlUrl" );

         if ( weblog == null )

             weblog = feed;

         if ( feed != null ) {

             listener.onItem( state, title, weblog, description, feed );

         } else if ( title != null ) {

             //this is almost certainly a folder

             listener.onFolder( state, title );

             onOutlineFolder( listener, state, current );

             listener.onFolderEnd();

         }

     }

 }