MemoryStorage.java

/*
 * This file or a portion of this file is licensed under the terms of
 * the Globus Toolkit Public License, found in file GTPL, or at
 * http://www.globus.org/toolkit/download/license.html. This notice must
 * appear in redistributions of this file, with or without modification.
 *
 * Redistributions of this Software, with or without modification, must
 * reproduce the GTPL in: (1) the Software, or (2) the Documentation or
 * some other similar material which is provided with the Software (if
 * any).
 *
 * Copyright 1999-2004 University of Chicago and The University of
 * Southern California. All rights reserved.
 */
package org.griphyn.vdl.parser;

import org.griphyn.vdl.classes.*;
import org.griphyn.vdl.util.*;
import org.xml.sax.*;
import java.util.List;
import java.util.ArrayList;

/**
 * This class adds a given Definition from the parser's callback into
 * the already established in-memory storage. 
 *
 * @author Jens-S. Vöckler
 * @author Yong Zhao
 * @version $Revision$
 */
public class MemoryStorage implements DefinitionHandler
{
  /**
   * This is a reference to the already established in-memory storage.
   */
  private Definitions m_memory;

  /**
   * This determines the behavior: insert mode (false) or update mode (true)
   */
  private boolean m_overwrite;

  /**
   * This variable determines whether to keep a list of rejects
   */
  private boolean m_dontcare;

  /**
   * This is the list of rejects for insert, or old values for update.
   */
  private ArrayList m_rejects;

  /**
   * The c'tor initializes the references to modify the in-memory database
   * of definitions.
   *
   * @param definitions is a reference to the in-memory database.
   * @param overwrite establishes insert or update mode.
   */
  public MemoryStorage( Definitions definitions,
			boolean overwrite, boolean dontcare )
  {
    if ( (this.m_memory = definitions) == null ) 
      throw new NullPointerException();
    this.m_overwrite = overwrite;
    this.m_dontcare = dontcare;
    this.m_rejects = new ArrayList();
  }

  /**
   * Accessor: Provide an iterator to walk the rejects list.
   * @return full access to the rejects list.
   */
  public java.util.List getRejects()
  {
    return this.m_rejects;
  }

  /**
   * This method adds the given Definition to whatever storage is
   * implemented underneath. 
   *
   * @param d is the Definition that is ready to be stored.
   * @return true, if new version was stored and database modified
   */
  public boolean store( Definition d )
  {
    int position = this.m_memory.positionOfDefinition(d);
    if ( position != -1 ) {
      // definition already exists
      if ( this.m_overwrite ) {
	Logging.instance().log( "app", 2, "Modifying " + d.shortID() );
	Definition old = this.m_memory.setDefinition( position, d );
	if ( ! this.m_dontcare ) this.m_rejects.add(old);
	return true;
      } else {
	Logging.instance().log( "app", 2, "Rejecting " + d.shortID() );
	if ( ! this.m_dontcare ) this.m_rejects.add(d);
	return false;
      }
    } else {
      // definition does not exist
      Logging.instance().log( "app", 2, "Adding " + d.shortID() );
      this.m_memory.addDefinition(d);
      return true;
    }
  }
}