package com.terradue.jcatalogue.client.internal.collections;
   
   /*
    *    Copyright 2011-2012 Terradue srl
    *
    *    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.
   */
  
  import java.net.URI;
  import java.util.Comparator;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.NoSuchElementException;
  import java.util.Set;
  import java.util.TreeMap;
  
  public final class Enclosures
      implements Comparator<Integer>, Iterable<URI>
  {
  
      private final Map<Integer, Set<URI>> enclosures = new TreeMap<Integer, Set<URI>>( this );
  
      public void addEnclosure( URI uri, Integer priority )
      {
          Set<URI> enclosuresSet = enclosures.get( priority );
  
          if ( enclosuresSet == null )
          {
              enclosuresSet = new HashSet<URI>();
              enclosures.put( priority, enclosuresSet );
          }
  
          enclosuresSet.add( uri );
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public Iterator<URI> iterator()
      {
          return new Iterator<URI>()
          {
  
              private Iterator<Integer> keys = enclosures.keySet().iterator();
  
              private Iterator<URI> pending = null;
  
              private URI next = null;
  
              @Override
              public boolean hasNext()
              {
                  if ( next != null )
                  {
                      return true;
                  }
  
                  while ( ( pending == null ) || !pending.hasNext() )
                  {
                      if ( !keys.hasNext() )
                      {
                          return false;
                      }
                      pending = enclosures.get( keys.next() ).iterator();
                  }
  
                  next = pending.next();
                  return true;
              }
  
              @Override
              public URI next()
              {
                  if ( !hasNext() )
                  {
                      throw new NoSuchElementException();
                  }
                  URI returned = next;
                  next = null;
                  return returned;
              }
  
              @Override
              public void remove()
              {
                  pending.remove();
              }
 
         };
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int compare( Integer o1, Integer o2 )
     {
         return o1.compareTo( o2 );
     }
 
 }