sortiteratorfilter.java

webwork source

/*
 * WebWork, Web Application Framework
 *
 * Distributable under Apache license.
 * See terms of license at opensource.org
 */
package webwork.util;

import org.apache.commons.logging.*;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.Comparator;
import java.util.List;
import java.util.Collections;

/**
 *	A bean that takes an iterator and outputs a subset of it.
 *
 *	@see <related>
 *	@author Rickard 謆erg ([e-mail])
 *	@version $Revision: 1.9 $
 */
public class SortIteratorFilter
   extends IteratorFilterSupport
   implements Iterator, webwork.action.Action
{
   // Attributes ----------------------------------------------------
   Object source;
   Comparator comparator;
   Iterator iterator;
   List list;

   // Public --------------------------------------------------------
   public void setSource(Object anIterator)
   {
      source = anIterator;
   }

   public void setComparator(Comparator aComparator)
   {
      this.comparator = aComparator;
   }

   public List getList()
   {
      return list;
   }
   // Action implementation -----------------------------------------
   public String execute()
   {
      if (source==null) {
         return ERROR;
      } else {
         try
         {
            if(!MakeIterator.isIterable(source)) {
              LogFactory.getLog(SortIteratorFilter.class.getName()).warn("Cannot create SortIterator for source " + source);
              return ERROR;
            }
            list = new ArrayList();
            Iterator i = MakeIterator.convert(source);
            while(i.hasNext()) {
               list.add(i.next());
            }
            // Sort it
            Collections.sort(list, comparator);
            iterator = list.iterator();

            return SUCCESS;
         } catch (Exception e)
         {
            LogFactory.getLog(SortIteratorFilter.class.getName()).warn("Error creating sort iterator.", e);
            return ERROR;
         }
      }
   }

   // Iterator implementation ---------------------------------------
   public boolean hasNext()
   {
      return (source==null) ? false : iterator.hasNext();
   }

   public Object next()
   {
      return iterator.next();
   }

   public void remove()
   {
      throw new UnsupportedOperationException("Remove is not supported in SortIteratorFilter.");
   }
}