org.datanucleus.identity

Class IdentityUtils

java.lang.Object

org.datanucleus.identity.IdentityUtils

public class IdentityUtils
extends Object

Series of utilities for handling identities of objects.

Constructor Summary

Constructors

Constructor and Description
IdentityUtils()

Method Summary

Modifier and Type	Method and Description
static Object	getApplicationIdentityForResultSetRow(ExecutionContext ec, AbstractClassMetaData cmd, Class pcClass, boolean inheritanceCheck, FieldManager resultsFM) Method to return the object application identity for a row of the result set.
static Class	getKeyTypeForSingleFieldIdentityType(Class idType) Accessor for the type of the single field application-identity key given the single field identity type.
static Object	getObjectFromIdString(String idStr, AbstractClassMetaData cmd, ExecutionContext ec, boolean checkInheritance) Convenience method to find an object given a string form of its identity, and the metadata for the class (or a superclass).
static Object	getObjectFromIdString(String idStr, AbstractMemberMetaData mmd, FieldRole fieldRole, ExecutionContext ec, boolean checkInheritance) Convenience method to find an object given a string form of its identity, and the metadata for the member.
static Object	getObjectFromPersistableIdentity(String persistableId, AbstractClassMetaData cmd, ExecutionContext ec) Convenience method to find an object given a string form of its identity, and the metadata for the class (or a superclass).
static String	getPersistableIdentityForId(Object id) Method to return a persistable form of the identity of a persistable object.
static String	getTargetClassNameForIdentity(Object id) Method to return the target class name of the persistable object that the provided identity represents.
static Object	getTargetKeyForDatastoreIdentity(Object id) Accessor for the key object for the specified datastore-identity.
static Object	getTargetKeyForSingleFieldIdentity(Object id) Accessor for the key object for the specified single field application-identity.
static Object	getValueForMemberInId(Object id, AbstractMemberMetaData pkMmd) Convenience method that interrogates a user-supplied object identity and returns the value of a particular member in that id.
static boolean	isDatastoreIdentity(Object id) Accessor for whether the provided id is datastore identity.
static boolean	isSingleFieldIdentity(Object id) Accessor for whether the passed identity is a valid single-field application-identity for this API.
static boolean	isSingleFieldIdentityClass(String className) Checks whether the passed class name is valid for a single field application-identity.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

IdentityUtils

public IdentityUtils()

Method Detail

isSingleFieldIdentityClass

public static boolean isSingleFieldIdentityClass(String className)

Checks whether the passed class name is valid for a single field application-identity.

Parameters:

className - the identity class name

Returns:

Whether it is a single field class

getTargetClassNameForIdentity

public static String getTargetClassNameForIdentity(Object id)

Method to return the target class name of the persistable object that the provided identity represents. For the cases of datastore-identity or single-field identity then utilises the accessor method on those identity types to get the targetClassName. For user-provided identity types checks for a

targetClassName

field and returns it if present. Otherwise returns null.

Parameters:

id - The identity

Returns:

Class name for the identity if easily determinable

isSingleFieldIdentity

public static boolean isSingleFieldIdentity(Object id)

Accessor for whether the passed identity is a valid single-field application-identity for this API.

Parameters:

id - The id

Returns:

Whether it is valid

isDatastoreIdentity

public static boolean isDatastoreIdentity(Object id)

Accessor for whether the provided id is datastore identity.

Parameters:

id - The identity to check

Returns:

Whether it is datastore identity

getTargetKeyForSingleFieldIdentity

public static Object getTargetKeyForSingleFieldIdentity(Object id)

Accessor for the key object for the specified single field application-identity.

Parameters:

id - The identity

Returns:

The key object

getTargetKeyForDatastoreIdentity

public static Object getTargetKeyForDatastoreIdentity(Object id)

Accessor for the key object for the specified datastore-identity.

Parameters:

id - The identity

Returns:

The key object

getKeyTypeForSingleFieldIdentityType

public static Class getKeyTypeForSingleFieldIdentityType(Class idType)

Accessor for the type of the single field application-identity key given the single field identity type.

Parameters:

idType - Single field identity type

Returns:

key type

getPersistableIdentityForId

public static String getPersistableIdentityForId(Object id)

Method to return a persistable form of the identity of a persistable object. This can be used by datastores that don't use foreign keys and want to store the explicit class of the persistable object.

Parameters:

id - The id

Returns:

String form

getObjectFromPersistableIdentity

public static Object getObjectFromPersistableIdentity(String persistableId,
                                                      AbstractClassMetaData cmd,
                                                      ExecutionContext ec)

Convenience method to find an object given a string form of its identity, and the metadata for the class (or a superclass).

Parameters:

persistableId - The persistable id

cmd - (Root) metadata for the class

ec - Execution Context

Returns:

The object

getApplicationIdentityForResultSetRow

public static Object getApplicationIdentityForResultSetRow(ExecutionContext ec,
                                                           AbstractClassMetaData cmd,
                                                           Class pcClass,
                                                           boolean inheritanceCheck,
                                                           FieldManager resultsFM)

Method to return the object application identity for a row of the result set. If the class isn't using application identity then returns null

Parameters:

ec - Execution Context

cmd - Metadata for the class

pcClass - The class required

inheritanceCheck - Whether need an inheritance check (may be for a subclass)

resultsFM - FieldManager servicing the results

Returns:

The identity (if found) or null (if either not sure of inheritance, or not known).

getValueForMemberInId

public static Object getValueForMemberInId(Object id,
                                           AbstractMemberMetaData pkMmd)

Convenience method that interrogates a user-supplied object identity and returns the value of a particular member in that id. A user-supplied PK has to provide either public/package/protected fields with the same names as the owning class, or getters for bean properties of the same name as the class members.

Parameters:

id - The (user-defined) identity

pkMmd - Metadata for the member that we require the value for

Returns:

The value for this member in the id

getObjectFromIdString

public static Object getObjectFromIdString(String idStr,
                                           AbstractClassMetaData cmd,
                                           ExecutionContext ec,
                                           boolean checkInheritance)

Convenience method to find an object given a string form of its identity, and the metadata for the class (or a superclass). Developers should move to using "persistable identity" and method getObjectFromPersistableIdentity().

Parameters:

idStr - The id string

cmd - Metadata for the class

ec - Execution Context

checkInheritance - Whether to check the inheritance level of this object

Returns:

The object

getObjectFromIdString

public static Object getObjectFromIdString(String idStr,
                                           AbstractMemberMetaData mmd,
                                           FieldRole fieldRole,
                                           ExecutionContext ec,
                                           boolean checkInheritance)

Convenience method to find an object given a string form of its identity, and the metadata for the member.

Parameters:

idStr - The id string

mmd - Metadata for the member

fieldRole - Role of this field (see org.datanucleus.metadata.FieldRole)

ec - Execution Context

checkInheritance - Whether to check the inheritance level of this object

Returns:

The object