org.apache.cayenne

Class ObjectId

java.lang.Object

org.apache.cayenne.ObjectId

All Implemented Interfaces:

Serializable

public class ObjectId
extends Object
implements Serializable

A portable global identifier for persistent objects. ObjectId can be temporary (used for transient or new uncommitted objects) or permanent (used for objects that have been already stored in DB). A temporary ObjectId stores object entity name and a pseudo-unique binary key; permanent id stores a map of values from an external persistent store (aka "primary key").

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected String	entityName
protected byte[]	key
protected Map<String,Object>	objectIdKeys
protected Map<String,Object>	replacementIdMap

Constructor Summary

Constructors

Constructor and Description
ObjectId(String entityName) Creates a TEMPORARY ObjectId.
ObjectId(String entityName, byte[] key) Creates a TEMPORARY id with a specified entity name and a binary key.
ObjectId(String entityName, Map<String,?> idMap) Creates a portable permanent ObjectId as a compound primary key.
ObjectId(String entityName, String key, int value) Creates a portable permanent ObjectId.
ObjectId(String entityName, String key, Object value) Creates a portable permanent ObjectId.

Method Summary

Modifier and Type	Method and Description
ObjectId	createReplacementId() Creates and returns a replacement ObjectId.
boolean	equals(Object object)
String	getEntityName()
Map<String,Object>	getIdSnapshot() Returns an unmodifiable Map of persistent id values, essentially a primary key map.
byte[]	getKey() Get the binary temporary object id.
Map<String,Object>	getReplacementIdMap() Returns a non-null mutable map that can be used to append replacement id values.
int	hashCode()
boolean	isReplacementIdAttached() Returns true if there is full or partial replacement id attached to this id.
boolean	isTemporary() Is this is temporary object id (used for objects which are not yet persisted to the data store).
String	toString() A standard toString method used for debugging.

Methods inherited from class java.lang.Object

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

Field Detail

entityName

protected String entityName

objectIdKeys

protected Map<String,Object> objectIdKeys

key

protected byte[] key

replacementIdMap

protected Map<String,Object> replacementIdMap

Constructor Detail

ObjectId

public ObjectId(String entityName)

Creates a TEMPORARY ObjectId. Assigns a generated unique key.

Since:

1.2

ObjectId

public ObjectId(String entityName,
                byte[] key)

Creates a TEMPORARY id with a specified entity name and a binary key. It is a caller responsibility to provide a globally unique binary key.

Since:

1.2

ObjectId

public ObjectId(String entityName,
                String key,
                int value)

Creates a portable permanent ObjectId.

Parameters:

entityName - The entity name which this object id is for

key - A key describing this object id, usually the attribute name for the primary key

value - The unique value for this object id

Since:

1.2

ObjectId

public ObjectId(String entityName,
                String key,
                Object value)

Creates a portable permanent ObjectId.

Parameters:

entityName - The entity name which this object id is for

key - A key describing this object id, usually the attribute name for the primary key

value - The unique value for this object id

Since:

1.2

ObjectId

public ObjectId(String entityName,
                Map<String,?> idMap)

Creates a portable permanent ObjectId as a compound primary key.

Parameters:

entityName - The entity name which this object id is for

idMap - Keys are usually the attribute names for each part of the primary key. Values are unique when taken as a whole.

Since:

1.2

Method Detail

isTemporary

public boolean isTemporary()

Is this is temporary object id (used for objects which are not yet persisted to the data store).

getEntityName

public String getEntityName()

Since:

1.2

getKey

public byte[] getKey()

Get the binary temporary object id. Null if this object id is permanent (persisted to the data store).

getIdSnapshot

public Map<String,Object> getIdSnapshot()

Returns an unmodifiable Map of persistent id values, essentially a primary key map. For temporary id returns replacement id, if it was already created. Otherwise returns an empty map.

equals

public boolean equals(Object object)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

getReplacementIdMap

public Map<String,Object> getReplacementIdMap()

Returns a non-null mutable map that can be used to append replacement id values. This allows to incrementally build a replacement GlobalID.

Since:

1.2

createReplacementId

public ObjectId createReplacementId()

Creates and returns a replacement ObjectId. No validation of ID is done.

Since:

1.2

isReplacementIdAttached

public boolean isReplacementIdAttached()

Returns true if there is full or partial replacement id attached to this id. This method is preferrable to "!getReplacementIdMap().isEmpty()" as it avoids unneeded replacement id map creation.

toString

public String toString()

A standard toString method used for debugging. It is guaranteed to produce the same string if two ObjectIds are equal.

Overrides:

toString in class Object