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 String	getClassNameForIdentitySimple(ApiAdapter api, Object id) Simple method to return the class name that the provided id represents.
static String	getIdentityAsString(ApiAdapter api, Object id) Convenience method to return the identity as a String.
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, int 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(ApiAdapter api, Object id) Method to return a persistable form of the identity of a persistable object.
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.

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

getClassNameForIdentitySimple

public static String getClassNameForIdentitySimple(ApiAdapter api,
                                                   Object id)

Simple method to return the class name that the provided id represents. If this is a datastore identity (OID) or single-field identity then returns the class name. Otherwise returns null. Does no inheritance checking.

Parameters:

api - The API adapter

id - The identity

Returns:

Class name for the identity if easily determinable

getPersistableIdentityForId

public static String getPersistableIdentityForId(ApiAdapter api,
                                                 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:

api - API adapter

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

getIdentityAsString

public static String getIdentityAsString(ApiAdapter api,
                                         Object id)

Convenience method to return the identity as a String. Typically outputs the toString() form of the identity object however with SingleFieldIdentity it outputs the class+key since SingleFieldIdentity just return the key.

Parameters:

id - The id

Returns:

String form

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).

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,
                                           int 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