persistentobject.java

把java对象映射成数据库表中的一条记录

/*
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 * License for the specific language governing rights and limitations under
 * the License.
 *
 * The Original Code is jRelationalFramework.
 *
 * The Initial Developer of the Original Code is is.com.
 * Portions created by is.com are Copyright (C) 2000 is.com.
 * All Rights Reserved.
 *
 * Contributor(s): Jonathan Carlson ([e-mail])
 * Contributor(s): ____________________________________
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License (the "GPL") or the GNU Lesser General
 * Public license (the "LGPL"), in which case the provisions of the GPL or
 * LGPL are applicable instead of those above.  If you wish to allow use of
 * your version of this file only under the terms of either the GPL or LGPL
 * and not to allow others to use your version of this file under the MPL,
 * indicate your decision by deleting the provisions above and replace them
 * with the notice and other provisions required by either the GPL or LGPL
 * License.  If you do not delete the provisions above, a recipient may use
 * your version of this file under either the MPL or GPL or LGPL License.
 *
 */
package com.is.jrf;

import java.io.Serializable;


/**
 * This is an abstract superclass for those objects wishing to participate
 * in the domain-object SQL framework.  When naming a variable for this, the
 * shortcut of aPO is often used.
 */
public abstract class PersistentObject
    implements Serializable
  {

  private PersistentState i_persistentState = PersistentState.NEW;

  public PersistentState getPersistentState()
    {
    return i_persistentState;
    }
  public void setPersistentState(PersistentState state)
    {
    i_persistentState = state;
    }

  /**
   * When true, this object is not in the database yet.  This method name is
   * somewhat cumbersome, however it is consistent, makes sense when you
   * think about it, and it won't conflict with business methods like
   * 'isNew()' or something similar would.
   *
   * @return a value of type 'boolean'
   */
  public boolean hasNewPersistentState()
    {
    return i_persistentState.isNewPersistentState();
    }

  /**
   * When true, this objects attributes do not match the database values.
   * This method name is somewhat cumbersome, however it is consistent,
   * makes sense when you think about it, and it won't conflict with
   * business methods like 'isModified()' or something similar would.
   *
   * @return a value of type 'boolean'
   */
  public boolean hasModifiedPersistentState()
    {
    return i_persistentState.isModifiedPersistentState();
    }

  /**
   * When true, this object's attributes match the database values.  This
   * method name is somewhat cumbersome, however it is consistent, makes
   * sense when you think about it, and it won't conflict with business
   * methods like 'isCurrent()' or something similar would.
   *
   * @return a value of type 'boolean'
   */
  public boolean hasCurrentPersistentState()
    {
    return i_persistentState.isCurrentPersistentState();
    }

  /**
   * When true, this object has already been saved to the database once while
   * ReturnSavedObject on the domain was set to true.  In this case, the
   * returned instance should replace the instance that was an argument to
   * save() to avoid saving old information to the database (columns can
   * change during the insert or update via triggers, optimistic locks,
   * timestamps, etc...).
   *
   * @return a value of type 'boolean'
   */
  public boolean hasDeadPersistentState()
    {
    return i_persistentState.isDeadPersistentState();
    }


  /* ==========  These methods may cause a state change  ========== */


  public void markNewPersistentState()
    {
    i_persistentState.markNewPersistentState(this);
    }

  /** State change will only occur if state is "Current" */
  public void markModifiedPersistentState()
    {
    i_persistentState.markModifiedPersistentState(this);
    }

  public void markCurrentPersistentState()
    {
    i_persistentState.markCurrentPersistentState(this);
    }

  public void markDeadPersistentState()
    {
    i_persistentState.markDeadPersistentState(this);
    }


  /* ==========  These methods force a state change  ========== */


  public void forceNewPersistentState()
    {
    if ( !(i_persistentState instanceof NewPersistentState))
        {
        i_persistentState = PersistentState.NEW;
        }
    }

  public void forceModifiedPersistentState()
    {
    if ( !(i_persistentState instanceof ModifiedPersistentState))
        {
        i_persistentState = PersistentState.MODIFIED;
        }
    }

  public void forceCurrentPersistentState()
    {
    if ( !(i_persistentState instanceof CurrentPersistentState))
        {
        i_persistentState = PersistentState.CURRENT;
        }
    }

  public void forceDeadPersistentState()
    {
    if ( !(i_persistentState instanceof DeadPersistentState))
        {
        i_persistentState = PersistentState.DEAD;
        }
    }


  } // PersistentObject