EDIT

package eu.etaxonomy.cdm.model.common;

import java.beans.PropertyChangeEvent;

import java.beans.PropertyChangeListener;

import java.beans.PropertyChangeSupport;

import java.io.Serializable;

import java.util.Calendar;

import java.util.UUID;

import javax.persistence.Basic;

import javax.persistence.FetchType;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.ManyToOne;

import javax.persistence.MappedSuperclass;

import javax.persistence.Temporal;

import javax.persistence.TemporalType;

import javax.persistence.Transient;

import org.hibernate.annotations.Cascade;

import org.hibernate.annotations.CascadeType;

import eu.etaxonomy.cdm.model.agent.Person;

/**

 * The base class for all CDM domain classes implementing UUIDs and bean property change event firing.

 * It provides a globally unique UUID and keeps track of creation date and person.

 * The UUID is the same for different versions (see {@link VersionableEntity}) of a CDM object, so a locally unique id exists in addition 

 * that allows to safely access and store several objects (=version) with the same UUID.

 * 

 * This class together with the {@link eu.etaxonomy.cdm.aspectj.PropertyChangeAspect} 

 * will fire bean change events to all registered listeners. Listener registration and event firing

 * is done with the help of the {@link PropertyChangeSupport} class.

 * 

 * @author markus

 *

 */

/**

 * @author markus

 *

 */

@MappedSuperclass

public abstract class CdmBase implements Serializable{

	private PropertyChangeSupport propertyChangeSupport = new PropertyChangeSupport(this);

	private int id;

	private UUID uuid;

	private Calendar created;

	private Person createdBy;

	/**

	 * Class constructor assigning a unique UUID and creation date.

	 * UUID can be changed later via setUuid method.

	 */

	public CdmBase() {

		this.uuid = UUID.randomUUID();

		this.setCreated(Calendar.getInstance());

	}

	/**

	 * see {@link PropertyChangeSupport#addPropertyChangeListener(PropertyChangeListener)}

	 * @param listener

	 */

	public void addPropertyChangeListener(PropertyChangeListener listener) {

		propertyChangeSupport.addPropertyChangeListener(listener);

	}

	/**

	 * see {@link PropertyChangeSupport#addPropertyChangeListener(String, PropertyChangeListener)}

	 * @param propertyName

	 * @param listener

	 */

	public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener) {

		propertyChangeSupport.addPropertyChangeListener(propertyName, listener);

	}

	/**

	 * see {@link PropertyChangeSupport#addPropertyChangeListener(PropertyChangeListener)}

	 * @param listener

	 */

	public void removePropertyChangeListener(PropertyChangeListener listener) {

		propertyChangeSupport.removePropertyChangeListener(listener);

	}

	/**

	 * @see PropertyChangeSupport#addPropertyChangeListener(String, PropertyChangeListener)

	 */

	public void removePropertyChangeListener(String propertyName, PropertyChangeListener listener) {

		propertyChangeSupport.removePropertyChangeListener(propertyName, listener);

	}

	@Transient

	public boolean hasListeners(String propertyName) {

		return propertyChangeSupport.hasListeners(propertyName);

	}

	public void firePropertyChange(String property, String oldval, String newval) {

		propertyChangeSupport.firePropertyChange(property, oldval, newval);

	}

	public void firePropertyChange(String property, int oldval, int newval) {

		propertyChangeSupport.firePropertyChange(property, oldval, newval);

	}

	public void firePropertyChange(String property, float oldval, float newval) {

		propertyChangeSupport.firePropertyChange(property, oldval, newval);

	}

	public void firePropertyChange(String property, boolean oldval, boolean newval) {

		propertyChangeSupport.firePropertyChange(property, oldval, newval);

	}

	public void firePropertyChange(String property, Object oldval, Object newval) {

		propertyChangeSupport.firePropertyChange(property, oldval, newval);

	}

	public void firePropertyChange(PropertyChangeEvent evt) {

		propertyChangeSupport.firePropertyChange(evt);

	}

	/**

	 * Returns local unique identifier for the concrete subclass

	 * @return

	 */

	@Id

	@GeneratedValue(generator = "system-increment")

	public int getId() {

		return this.id;

	}

	/**

	 * Assigns a unique local ID to this object. 

	 * Because of the EJB3 @Id and @GeneratedValue annotation this id will be

	 * set automatically by the persistence framework when object is saved.

	 * @param id

	 */

	public void setId(int id) {

		this.id = id;

	}

	/**

	 * Method for hibernate only to read the UUID value as a simple string from the object and persist it (e.g. in a database).

	 * For reading the UUID please use getUuid method

	 * @return String representation of the UUID

	 */

	private String getStrUuid() {

		return this.uuid.toString();

	}

	/**

	 * Method for hibernate only to set the UUID value as a simple string as it was stored in the persistence layer (e.g. a database).

	 * For setting the UUID please use setUuid method

	 */

	private void setStrUuid(String uuid) {

		this.uuid = UUID.fromString(uuid);

	}

	@Transient

	public UUID getUuid() {

		return this.uuid;

	}

	public void setUuid(UUID uuid) {

		this.uuid = uuid;

	}

	@Temporal(TemporalType.TIMESTAMP)

	@Basic(fetch = FetchType.LAZY)

	public Calendar getCreated() {

		return created;

	}

	/**

	 * Sets the timestamp this object was created. 

	 * Most databases cannot store milliseconds, so they are removed by this method.

	 * Caution: We are planning to replace the Calendar class with a different datetime representation which is more suitable for hibernate

	 * see {@link http://dev.e-taxonomy.eu/trac/ticket/247 TRAC ticket} 

	 * 

	 * @param created

	 */

	public void setCreated(Calendar created) {

		if (created != null){

			created.set(Calendar.MILLISECOND, 0);

		}

		this.created = created;

	}

	@ManyToOne(fetch=FetchType.LAZY)

	@Cascade( { CascadeType.SAVE_UPDATE })

	public Person getCreatedBy() {

		return this.createdBy;

	}

	public void setCreatedBy(Person createdBy) {

		this.createdBy = createdBy;

	}

	/**

	 * Is true if UUID and created timestamp are the same for the passed Object and this one.

	 * @see java.lang.Object#equals(java.lang.Object)

	 */

	@Override

	public boolean equals(Object obj) {

		if (obj == null){

			return false;

		}else if (CdmBase.class.isAssignableFrom(obj.getClass())){

			CdmBase cdmObj = (CdmBase)obj;

			boolean uuidEqual = cdmObj.getUuid().equals(this.getUuid());

			boolean createdEqual = cdmObj.getCreated().equals(this.getCreated());

			if (uuidEqual && createdEqual){

				return true;

			}

		}

		return false;

	}

	/**

	 * Returns the class, id and uuid as a string for any CDM object. 

	 * For example: Taxon#13<b5938a98-c1de-4dda-b040-d5cc5bfb3bc0>

	 * @see java.lang.Object#toString()

	 */

	@Override

	public String toString() {

		return this.getClass().getSimpleName()+"#"+this.getId()+"<"+this.getUuid()+">";

	}

}