com.caucho.v5.kelp.StreamKelp Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of baratine Show documentation
A reactive Java web server.
There is a newer version: 1.0.1
/*
 * Copyright (c) 1998-2015 Caucho Technology -- all rights reserved
 *
 * This file is part of Baratine(TM)
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Baratine is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Baratine 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Baratine; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package com.caucho.v5.kelp;

import java.util.Objects;
import java.util.function.Predicate;


/**
 * iterator across the btree.
 */
class StreamKelp
{
  private final TableKelp _table;
  
  private final RowCursor _min;
  private final RowCursor _max;
  private final Predicate _predicate;
  
  private final MapKelp _map;
  
  private final RowCursor _indexCursor;
  private final RowCursor _cursor;
    
  private PageLeaf _leaf;
  
  private boolean _isData = true;
    
  StreamKelp(TableKelp table,
             RowCursor min,
             RowCursor max,
             Predicate predicate,
             MapKelp map)
  {
    Objects.requireNonNull(predicate);
    Objects.requireNonNull(map);
    
    _table = table;
    
    _min = min;
    _max = max;
    
    _predicate = predicate;
    _map = map;
    
    _indexCursor = _table.cursor();
    _cursor = _table.cursor();
      
    _indexCursor.setKey(_min);
      
    _leaf = _table.getTableService().getLeafByCursor(_indexCursor);
  }
  
  void setData(boolean isData)
  {
    _isData = isData;
  }
    
  public boolean next()
  {
    while (_leaf != null) {
      if (_indexCursor.compareTo(_max) > 0) {
        _leaf = null;
        
        return false;
      }

      _cursor.setKey(_max);

      _leaf = _leaf.first(_table, _indexCursor, _cursor);

      if (_leaf == null) {
        return false;
      }

      _indexCursor.setKey(_cursor);

      if ((! _isData || _cursor.isData()) && _predicate.test(_cursor)) {
        _map.onRow(_cursor);
      }
      
      _indexCursor.incrementKey();
    }
    
    return false;
  }
}