net.sf.mmm.util.transferobject.api

Class EntityTo<ID>

java.lang.Object

net.sf.mmm.util.transferobject.api.AbstractTransferObject

net.sf.mmm.util.transferobject.api.DataTo

net.sf.mmm.util.transferobject.api.EntityTo<ID>

Type Parameters:

ID - is the type of the primary key.

All Implemented Interfaces:

Serializable, Cloneable, Entity, GenericEntity<ID>, MutableGenericEntity<ID>, MutableRevisionedEntity<ID>, RevisionedEntity<ID>, AttributeReadId<ID>, TransferObject

public abstract class EntityTo<ID>
extends DataTo
implements MutableRevisionedEntity<ID>

This is the abstract base class for an DTO corresponding to a PersistenceEntity. Classes derived from this class should carry the suffix Eto.
For additional details and an example consult the package JavaDoc.

Since:

3.1.0

Author:

Joerg Hohwiller (hohwille at users.sourceforge.net)

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	EntityTo.PersistentEntityAccess Inner class to grant access to internal PersistenceEntity reference of an EntityTo.

Field Summary

Fields

Modifier and Type	Field and Description
private ID	id
private int	modificationCounter
private GenericEntity<ID>	persistentEntity
private Number	revision
private static long	serialVersionUID UID for serialization.

Fields inherited from interface net.sf.mmm.util.entity.api.RevisionedEntity

LATEST_REVISION

Constructor Summary

Constructors

Constructor and Description
EntityTo() The constructor.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj)
ID	getId() This method gets the unique identifier (primary key) of this entity.
int	getModificationCounter() This method gets the current modification-counter of this entity.
Number	getRevision() This method gets the revision of this entity.
int	hashCode()
void	setId(ID id) This method sets the ID of this entity.
void	setModificationCounter(int version) This method sets the modification counter of this entity.
void	setRevision(Number revision) This method sets the revision of this entity.
protected void	toString(StringBuilder buffer) Method to extend AbstractTransferObject.toString() logic.
private void	writeobject(ObjectOutputStream o) Force update of modification counter for serialization.

Methods inherited from class net.sf.mmm.util.transferobject.api.AbstractTransferObject

clone, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

serialVersionUID

private static final long serialVersionUID

UID for serialization.

See Also:

Constant Field Values

id

private ID id

See Also:

getId()

modificationCounter

private int modificationCounter

See Also:

getModificationCounter()

revision

private Number revision

See Also:

getRevision()

persistentEntity

private transient GenericEntity<ID> persistentEntity

See Also:

getModificationCounter()

Constructor Detail

EntityTo

public EntityTo()

The constructor.

Method Detail

getId

public ID getId()

This method gets the unique identifier (primary key) of this entity. While this method is initially defined in a generic way, it is strongly recommended to use Long as datatype for IDs.
Even if you want to have a String-based business-oriented identifier it is best practice to use a Long as primary key and add the business identifier as additional field (with a unique constraint). This way references to the entity will be a lot more compact and improve your performance in JOINs or the like. However, there may be reasons to use other datatypes for the ID. In any case the unique ID should be an immutable java-object that can be rebuild from its string-representation.
Please note that if your ID has a specific syntax, semantic, formatting rules, etc. you should create a custom Datatype for it. If it can easily be mapped to a Long value you can still use Long here and provide a transient getter method that returns the your custom Datatype from the Long.

Specified by:

getId in interface GenericEntity<ID>

Specified by:

getId in interface AttributeReadId<ID>

Returns:

the ID of this entity. It may be null if the object is new and no ID has manually been assigned.

setId

public void setId(ID id)

This method sets the ID of this entity.
ATTENTION:
This operation should only be used in specific cases and if you are aware of what you are doing. Typically the ID is a GeneratedValue and therefore managed by the persistence. However, for final freedom we decided to add this method to the API (e.g. to copy from transfer-object to persistent-entity and vice-versa).

Specified by:

setId in interface MutableGenericEntity<ID>

Parameters:

id - is the new value of GenericEntity.getId().

getModificationCounter

public int getModificationCounter()

This method gets the current modification-counter of this entity. Whenever the object gets modified and saved, this counter will be increased. The initial value after construction is 0.
If this feature is NOT supported for some reason, this method should always return 0.
NOTE:
EntityTo can carry a hidden reference to a PersistenceEntity. This is set by TransferObjectUtil.convertFromEntity(net.sf.mmm.util.entity.api.PersistenceEntity, Class) and related functions. In such case the modification counter is updated from that reference by this method as an intended side effect. This is done because JPA implementations will typically update the modification counter only after the transaction has been committed and the conversion of an entity to ETO typically happens before. This approach is better and more robust than flushing.

Specified by:

getModificationCounter in interface GenericEntity<ID>

Returns:

the current modification-counter.

See Also:

Version

setModificationCounter

public void setModificationCounter(int version)

This method sets the modification counter of this entity.
ATTENTION:
This operation should only be used in specific cases and if you are aware of what you are doing as this attribute is managed by the persistence. However, for final freedom we decided to add this method to the API (e.g. to copy from transfer-object to persistent-entity and vice-versa).

Specified by:

setModificationCounter in interface MutableGenericEntity<ID>

Parameters:

version - is the new value of GenericEntity.getModificationCounter().

getRevision

public Number getRevision()

This method gets the revision of this entity. The latest revision of an entity will always return null. Otherwise this object is a historic entity and it will be read-only so modifications are NOT permitted.

Specified by:

getRevision in interface RevisionedEntity<ID>

Returns:

the revision or RevisionedEntity.LATEST_REVISION (null) if this is the latest revision.

setRevision

public void setRevision(Number revision)

This method sets the revision of this entity.
ATTENTION:
This operation should only be used in specific cases and if you are aware of what you are doing as this attribute is managed by the persistence. However, for final freedom we decided to add this method to the API (e.g. to copy from transfer-object to persistent-entity and vice-versa).

Specified by:

setRevision in interface MutableRevisionedEntity<ID>

Parameters:

revision - is the new value of RevisionedEntity.getRevision().

hashCode

public int hashCode()

Overrides:

hashCode in class AbstractTransferObject

equals

public boolean equals(Object obj)

Overrides:

equals in class AbstractTransferObject

toString

protected void toString(StringBuilder buffer)

Method to extend AbstractTransferObject.toString() logic.

Overrides:

toString in class AbstractTransferObject

Parameters:

buffer - is the StringBuilder where to append the string representation.

writeobject

private void writeobject(ObjectOutputStream o)
                  throws IOException

Force update of modification counter for serialization.

Parameters:

o - is the ObjectOutputStream where to write the serialized object data to.

Throws:

IOException - in case of an I/O error.