/*
    * This software was designed and created by Jason Carroll.
    * Copyright (c) 2002, 2003, 2004 Jason Carroll.
    * The author can be reached at jcarroll@cowsultants.com
    * ITracker website: http://www.cowsultants.com
    * ITracker forums: http://www.cowsultants.com/phpBB/index.php
    *
    * This program is free software; you can redistribute it and/or modify
    * it only 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.
   *
   * This program 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.  See the
   * GNU General Public License for more details.
   */
  
  package org.itracker.model;
  
  import java.io.Serializable;
  import java.util.Comparator;
  import java.util.Date;
  
  import org.apache.commons.lang.builder.CompareToBuilder;
  import org.apache.commons.lang.builder.EqualsBuilder;
  import org.apache.commons.lang.builder.HashCodeBuilder;
  
  /**
   * This is a POJO Business Domain Object. Hibernate Bean.
   * 
   * <p>
   * All entities are Java Beans and should inherit this class to make sure they
   * are Serializable and Cloneable and have the following fields : an id, a
   * creation date and a last modifiation date.
   * </p>
   * 
   * @author ready
   */
  public abstract class AbstractEntity implements Entity {
  
  	/**
  	 * 
  	 */
  	private static final long serialVersionUID = 1L;
  
  	public static final Comparator<Entity> ID_COMPARATOR = new IdComparator();
  
  	public static final Comparator<AbstractEntity> CREATE_DATE_COMPARATOR = new CreateDateComparator();
  
  	public static final Comparator<AbstractEntity> LAST_MODIFIED_DATE_COMPARATOR = new LastModifiedDateComparator();
  
  	/** System ID */
  	private Integer id;
  
  	/** Creation date and time. */
  	private Date createDate = new Date();
  
  	/** Last modification date and time. */
  	private Date lastModifiedDate = new Date();
  
  	/**
  	 * Default constructor (required by Hibernate).
  	 */
  	public AbstractEntity() {
  	}
  
  	public Integer getId() {
  		return id;
  	}
  
  	public void setId(Integer id) {
  		this.id = id;
  	}
  
  	/**
  	 * @return creation time stamp or <tt>null</tt> for transient entities
  	 */
  	public Date getCreateDate() {
  		if (null == createDate)
  			createDate = new Date();
  		return new Date(createDate.getTime());
  	}
  
  	/**
  	 * Sets the creation date and time.
  	 * 
  	 * <p>
  	 * The persistence framework automatically sets this property when a new
  	 * entity is persisted. <br>
  	 * Note that the value is managed by the persistence framework and may be
  	 * generated by the database in the future.
  	 * </p>
  	 * 
  	 * <p>
  	 * The creation time stamp should never change once initialized.
  	 * </p>
  	 * 
  	 * @param dateTime
 	 *            creation time stamp
 	 */
 	public void setCreateDate(Date dateTime) {
 		if (null == dateTime)
 			return;
 		this.createDate = new Date(dateTime.getTime());
 	}
 
 	/**
 	 * @return last modification time stamp or <tt>null</tt> for transient
 	 *         entities
 	 */
 	public Date getLastModifiedDate() {
 		if (null == this.lastModifiedDate)
 			this.lastModifiedDate = new Date();
 		return new Date(lastModifiedDate.getTime());
 	}
 
 	/**
 	 * Sets the last modification date and time.
 	 * 
 	 * <p>
 	 * The persistence framework automatically sets this property to the same
 	 * value as the createDate property when persisting a new entity and
 	 * automatically updates it when saving an existing one. <br>
 	 * Note that the value is managed by the persistence framework and may be
 	 * generated by the database in the future.
 	 * </p>
 	 * 
 	 * @param dateTime
 	 *            last modification time stamp
 	 */
 	public void setLastModifiedDate(Date dateTime) {
 		if (null == dateTime)
 			return;
 		this.lastModifiedDate = new Date(dateTime.getTime());
 	}
 
 	/**
 	 * Returns whether this instance represents a new transient instance.
 	 * 
 	 * @return <tt>true</tt> if <code>id</code> is <tt>null</tt>
 	 */
 	public boolean isNew() {
 		return (this.getId() == null);
 	}
 
 	@Override
 	public Object clone() throws CloneNotSupportedException {
 		return super.clone();
 	}
 
 	/**
 	 * Compares 2 instances by ID.
 	 */
 	protected static class IdComparator implements Comparator<Entity>, Serializable {
 		
 		/**
 		 * 
 		 */
 		private static final long serialVersionUID = 1L;
 
 		public int compare(Entity a, Entity b) {
 			return new CompareToBuilder().append(a.getId(), b.getId())
 					.toComparison();
 		}
 
 	}
 
 	protected static class CreateDateComparator implements
 			Comparator<AbstractEntity>, Serializable {
 		
 		/**
 		 * 
 		 */
 		private static final long serialVersionUID = 1L;
 		
 		public int compare(AbstractEntity a, AbstractEntity b) {
 			return new CompareToBuilder().append(a.getCreateDate(),
 					b.getCreateDate()).toComparison();
 		}
 
 	}
 
 	/**
 	 * Compares 2 instances by last modified date.
 	 */
 	protected static class LastModifiedDateComparator implements
 			Comparator<AbstractEntity>, Serializable {
 		
 		/**
 		 * 
 		 */
 		private static final long serialVersionUID = 1L;
 		
 		public int compare(AbstractEntity a, AbstractEntity b) {
 			return new CompareToBuilder().append(a.getLastModifiedDate(),
 					b.getLastModifiedDate()).toComparison();
 		}
 
 	}
 
 	@Override
 	public final boolean equals(Object obj) {
 
 		if (this == obj) {
 			return true;
 		}
 		if (isNew() || null == obj) {
 			return false;
 		}
 
 		if (getClass().equals(obj.getClass())) {
 			Entity o = (Entity) obj;
 			return new EqualsBuilder()
 					.append(getId(), o.getId()).isEquals();
 
 		}
 
 		return false;
 
 	}
 
 	public final int compareTo(Entity o) {
 		if (this.equals(o)) {
 			return 0;
 		}
 		return new CompareToBuilder().append(getClass(), o.getClass(), AbstractEntity.CLASS_COMPARATOR).append(
 				getId(), o.getId()).toComparison();
 	}
 
 	@Override
 	public final int hashCode() {
 		return new HashCodeBuilder().append(getClass()).append(getId()).toHashCode();
 
 	}
 	
 	private static final Comparator<Class<?>> CLASS_COMPARATOR = new Comparator<Class<?>>() {
 		public int compare(Class<?> o1, Class<?> o2) {
 			return new CompareToBuilder().append(o1.getSimpleName(), o2.getSimpleName()).append(o1.hashCode(), hashCode()).toComparison();
 		}
 	};
 
 }