/*
 * Copyright (c) 2003-2008, Franz-Josef Elmer, 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.
 *
 * 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 THE COPYRIGHT OWNER OR 
 * CONTRIBUTORS 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 classycle.dependency;

import classycle.graph.AtomicVertex;

/**
 * Processor of {@link Statement Statements} as defined in a 
 * dependency definition file.
 * 
 * @author  Franz-Josef Elmer
 */
public class DependencyProcessor
{
  private final Statement[] _statements;
  private int _index;
  
  /**
   * Creates a new instance for the specified dependency definition. It also
   * parses the definition and creates all {@link Statement Statements}.
   * 
   * @param dependencyDefinition Dependency definition as read from a
   *        .ddf file.
   * @param properties Contains predefined properties and will also
   *        be populated by definition in <code>dependencyDefinition</code>.
   * @param renderer Renderer for processing results.
   * @throws IllegalArgumentException if <tt>dependencyDefinition</tt> 
   *        is invalid.
   */
  public DependencyProcessor(String dependencyDefinition, 
                             DependencyProperties properties, 
                             ResultRenderer renderer) 
  {
    _statements = new DependencyDefinitionParser(dependencyDefinition, 
                                                 properties, 
                                                 renderer).getStatements();
  }
  
  /**
   * Returns <tt>true</tt> if there are still unprocessed statements.
   * @return
   */
  public boolean hasMoreStatements() {
    return _index < _statements.length;
  }
  
  /**
   * Executes the next unprocessed statement and returns its result.
   * @param graph The graph to be checked by the statement.
   * @return <tt>null</tt> if there is no unprocessed statement.
   */
  public Result executeNextStatement(AtomicVertex[] graph) {
    return hasMoreStatements() ? _statements[_index++].execute(graph) : null;
  }
}
