JDOImplHelper (JDO API 3.2)

java.lang.Object
- javax.jdo.spi.JDOImplHelper

```
public class JDOImplHelper
extends Object
```
This class is a helper class for JDO implementations. It contains methods to register metadata for persistence-capable classes and to perform common operations needed by implementations, not by end users.
JDOImplHelper allows construction of instances of persistence-capable classes without using reflection.
Persistence-capable classes register themselves via a static method at class load time. There is no security restriction on this access. JDO implementations get access to the functions provided by this class only if they are authorized by the security manager. To avoid having every call go through the security manager, only the call to get an instance is checked. Once an implementation has an instance, any of the methods can be invoked without security checks.

Version:

2.1

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static interface`	`JDOImplHelper.StateInterrogationBooleanReturn` This is an interface used to interrogate the state of an instance that does not implement PersistenceCapable.
`static interface`	`JDOImplHelper.StateInterrogationObjectReturn` This is an interface used to interrogate the state of an instance that does not implement PersistenceCapable.
`static interface`	`JDOImplHelper.StringConstructor` Construct an instance of a key class using a String as input.

Field Summary

Fields
Modifier and Type Field and Description

static Set<String> USER_CONFIGURABLE_STANDARD_PROPERTIES
JDO standard properties that the user can configure.

Fields
Modifier and Type	Field and Description
`static Set<String>`	`USER_CONFIGURABLE_STANDARD_PROPERTIES` JDO standard properties that the user can configure.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addRegisterClassListener(RegisterClassListener crl)` Add the specified `RegisterClassListener` to the listener list.
`void`	`addStateInterrogation(StateInterrogation si)` Add a StateInterrogation to the list.
`static void`	`assertOnlyKnownStandardProperties(Map<?,?> properties)` Examines the given map for keys beginning with the JDO standard prefix, `Constants.JAVAX_JDO_PREFIX`.
`static void`	`checkAuthorizedStateManager(StateManager sm)` Check that the parameter instance is of a class that is authorized for JDOPermission("setStateManager").
`static void`	`checkAuthorizedStateManagerClass(Class smClass)` Check that the parameter instance is a class that is authorized for JDOPermission("setStateManager").
`static Object`	`construct(String className, String keyString)` Construct an instance of the parameter class, using the keyString as an argument to the constructor.
`void`	`copyKeyFieldsFromObjectId(Class pcClass, PersistenceCapable.ObjectIdFieldConsumer fm, Object oid)` Copy fields to an outside source from the key fields in the ObjectId.
`void`	`copyKeyFieldsToObjectId(Class pcClass, PersistenceCapable.ObjectIdFieldSupplier fm, Object oid)` Copy fields from an outside source to the key fields in the ObjectId.
`byte[]`	`getFieldFlags(Class pcClass)` Get the field flags for a `PersistenceCapable` class.
`String[]`	`getFieldNames(Class pcClass)` Get the field names for a `PersistenceCapable` class.
`Class[]`	`getFieldTypes(Class pcClass)` Get the field types for a `PersistenceCapable` class.
`static JDOImplHelper`	`getInstance()` Get an instance of `JDOImplHelper`.
`Class`	`getPersistenceCapableSuperclass(Class pcClass)` Get the persistence-capable superclass for a `PersistenceCapable` class.
`Collection<Class>`	`getRegisteredClasses()` Returns a collection of class objects of the registered persistence-capable classes.
`static DocumentBuilderFactory`	`getRegisteredDocumentBuilderFactory()` Return the registered instance of DocumentBuilderFactory.
`static ErrorHandler`	`getRegisteredErrorHandler()` Return the registered instance of ErrorHandler.
`PersistenceCapable`	`newInstance(Class pcClass, StateManager sm)` Create a new instance of the class and assign its `jdoStateManager`.
`PersistenceCapable`	`newInstance(Class pcClass, StateManager sm, Object oid)` Create a new instance of the class and assign its `jdoStateManager` and key values from the ObjectId.
`Object`	`newObjectIdInstance(Class pcClass)` Create a new instance of the ObjectId class of this `PersistenceCapable` class.
`Object`	`newObjectIdInstance(Class pcClass, Object obj)` Create a new instance of the class used by the parameter Class for JDO identity, using the key constructor of the object id class.
`Object`	`nonBinaryCompatibleGet(Object pc, JDOImplHelper.StateInterrogationObjectReturn sibr)` Return an object associated with a non-binary-compatible instance.
`boolean`	`nonBinaryCompatibleIs(Object pc, JDOImplHelper.StateInterrogationBooleanReturn sibr)` Determine the state of a non-binary-compatible instance.
`void`	`nonBinaryCompatibleMakeDirty(Object pc, String fieldName)` Mark a non-binary-compatible instance dirty.
`static void`	`registerAuthorizedStateManagerClass(Class smClass)` Register a class authorized to replaceStateManager.
`static void`	`registerAuthorizedStateManagerClasses(Collection smClasses)` Register classes authorized to replaceStateManager.
`static void`	`registerClass(Class pcClass, String[] fieldNames, Class[] fieldTypes, byte[] fieldFlags, Class persistenceCapableSuperclass, PersistenceCapable pc)` Register metadata by class.
`void`	`registerDateFormat(DateFormat df)` Register a DateFormat instance for use with constructing Date instances.
`void`	`registerDocumentBuilderFactory(DocumentBuilderFactory factory)` Register a DocumentBuilderFactory instance for use in parsing the resource(s) META-INF/jdoconfig.xml.
`void`	`registerErrorHandler(ErrorHandler handler)` Register an ErrorHandler instance for use in parsing the resource(s) META-INF/jdoconfig.xml.
`Object`	`registerStringConstructor(Class cls, JDOImplHelper.StringConstructor sc)` Register special StringConstructor instances.
`void`	`removeRegisterClassListener(RegisterClassListener crl)` Remove the specified `RegisterClassListener` from the listener list.
`void`	`removeStateInterrogation(StateInterrogation si)` Remove a StateInterrogation from the list.
`void`	`unregisterClass(Class pcClass)` Unregister metadata by class.
`void`	`unregisterClasses(ClassLoader cl)` Unregister metadata by class loader.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - USER_CONFIGURABLE_STANDARD_PROPERTIES
```
public static final Set<String> USER_CONFIGURABLE_STANDARD_PROPERTIES
```
    JDO standard properties that the user can configure.
- Method Detail
  - getInstance
```
public static JDOImplHelper getInstance()
                                 throws SecurityException
```
    Get an instance of JDOImplHelper. This method checks that the caller is authorized for JDOPermission("getMetadata"), and if not, throws SecurityException.
    
    Returns:
    
    an instance of JDOImplHelper.
    
    Throws:
    
    SecurityException - if the caller is not authorized for JDOPermission("getMetadata").
  - getFieldNames
```
public String[] getFieldNames(Class pcClass)
```
    Get the field names for a PersistenceCapable class. The order of fields is the natural ordering of the String class (without considering localization).
    
    Parameters:
    
    pcClass - the PersistenceCapable class.
    
    Returns:
    
    the field names for the class.
  - getFieldTypes
```
public Class[] getFieldTypes(Class pcClass)
```
    Get the field types for a PersistenceCapable class. The order of fields is the same as for field names.
    
    Parameters:
    
    pcClass - the PersistenceCapable class.
    
    Returns:
    
    the field types for the class.
  - getFieldFlags
```
public byte[] getFieldFlags(Class pcClass)
```
    Get the field flags for a PersistenceCapable class. The order of fields is the same as for field names.
    
    Parameters:
    
    pcClass - the PersistenceCapable class.
    
    Returns:
    
    the field types for the class.
  - getPersistenceCapableSuperclass
```
public Class getPersistenceCapableSuperclass(Class pcClass)
```
    Get the persistence-capable superclass for a PersistenceCapable class.
    
    Parameters:
    
    pcClass - the PersistenceCapable class.
    
    Returns:
    
    The PersistenceCapable superclass for this class, or null if there isn't one.
  - newInstance
```
public PersistenceCapable newInstance(Class pcClass,
                                      StateManager sm)
```
    Create a new instance of the class and assign its jdoStateManager. The new instance has its jdoFlags set to LOAD_REQUIRED.
    
    Parameters:
    
    pcClass - the PersistenceCapable class.
    
    sm - the StateManager which will own the new instance.
    
    Returns:
    
    the new instance, or null if the class is not registered.
    
    See Also:
    
    PersistenceCapable.jdoNewInstance(StateManager sm)
  - newInstance
```
public PersistenceCapable newInstance(Class pcClass,
                                      StateManager sm,
                                      Object oid)
```
    Create a new instance of the class and assign its jdoStateManager and key values from the ObjectId. If the oid parameter is null, no key values are copied. The new instance has its jdoFlags set to LOAD_REQUIRED.
    
    Parameters:
    
    pcClass - the PersistenceCapable class.
    
    sm - the StateManager which will own the new instance.
    
    oid - the ObjectId instance from which to copy key field values.
    
    Returns:
    
    the new instance, or null if the class is not registered.
    
    See Also:
    
    PersistenceCapable.jdoNewInstance(StateManager sm, Object oid)
  - newObjectIdInstance
```
public Object newObjectIdInstance(Class pcClass)
```
    Create a new instance of the ObjectId class of this PersistenceCapable class. It is intended only for application identity. This method should not be called for classes that use single field identity; newObjectIdInstance(Class, Object) should be used instead. If the class has been enhanced for datastore identity, or if the class is abstract, null is returned.
    
    Parameters:
    
    pcClass - the PersistenceCapable class.
    
    Returns:
    
    the new ObjectId instance, or null if the class is not registered.
  - newObjectIdInstance
```
public Object newObjectIdInstance(Class pcClass,
                                  Object obj)
```
    Create a new instance of the class used by the parameter Class for JDO identity, using the key constructor of the object id class. It is intended for single field identity. The identity instance returned has no relationship with the values of the primary key fields of the persistence-capable instance on which the method is called. If the key is the wrong class for the object id class, null is returned.
    For classes that use single field identity, if the parameter is of one of the following types, the behavior must be as specified:
    - Number or Character: the parameter must be the single field type or the wrapper class of the primitive field type; the parameter is passed to the single field identity constructor
    - ObjectIdFieldSupplier: the field value is fetched from the ObjectIdFieldSupplier and passed to the single field identity constructor
    - String: the String is passed to the single field identity constructor
    Parameters:
    
    obj - the Object form of the object id
    
    pcClass - the PersistenceCapable class.
    
    Returns:
    
    the new ObjectId instance, or null if the class is not registered.
    
    Since:
    
    2.0
  - copyKeyFieldsToObjectId
```
public void copyKeyFieldsToObjectId(Class pcClass,
                                    PersistenceCapable.ObjectIdFieldSupplier fm,
                                    Object oid)
```
    Copy fields from an outside source to the key fields in the ObjectId. This method is generated in the PersistenceCapable class to generate a call to the field manager for each key field in the ObjectId.
    For example, an ObjectId class that has three key fields (int id, String name, and Float salary) would have the method generated:
    void jdoCopyKeyFieldsToObjectId (Object oid, ObjectIdFieldSupplier fm) { oid.id = fm.fetchIntField (0); oid.name = fm.fetchStringField (1); oid.salary = fm.fetchObjectField (2); }
    The implementation is responsible for implementing the ObjectIdFieldSupplier to provide the values for the key fields.
    
    Parameters:
    
    pcClass - the PersistenceCapable Class.
    
    oid - the ObjectId target of the copy.
    
    fm - the field manager that supplies the field values.
  - copyKeyFieldsFromObjectId
```
public void copyKeyFieldsFromObjectId(Class pcClass,
                                      PersistenceCapable.ObjectIdFieldConsumer fm,
                                      Object oid)
```
    Copy fields to an outside source from the key fields in the ObjectId. This method is generated in the PersistenceCapable class to generate a call to the field manager for each key field in the ObjectId. For example, an ObjectId class that has three key fields (int id, String name, and Float salary) would have the method generated:
    void jdoCopyKeyFieldsFromObjectId (PersistenceCapable oid, ObjectIdFieldConsumer fm) { fm.storeIntField (0, oid.id); fm.storeStringField (1, oid.name); fm.storeObjectField (2, oid.salary); }
    The implementation is responsible for implementing the ObjectIdFieldConsumer to store the values for the key fields.
    
    Parameters:
    
    pcClass - the PersistenceCapable class
    
    oid - the ObjectId source of the copy.
    
    fm - the field manager that receives the field values.
  - registerClass
```
public static void registerClass(Class pcClass,
                                 String[] fieldNames,
                                 Class[] fieldTypes,
                                 byte[] fieldFlags,
                                 Class persistenceCapableSuperclass,
                                 PersistenceCapable pc)
```
    Register metadata by class. The registration will be done in the class named JDOImplHelper loaded by the same or an ancestor class loader as the PersistenceCapable class performing the registration.
    
    Parameters:
    
    pcClass - the PersistenceCapable class used as the key for lookup.
    
    fieldNames - an array of String field names for persistent and transactional fields
    
    fieldTypes - an array of Class field types
    
    fieldFlags - the Field Flags for persistent and transactional fields
    
    pc - an instance of the PersistenceCapable class
    
    persistenceCapableSuperclass - the most immediate superclass that is PersistenceCapable
  - unregisterClasses
```
public void unregisterClasses(ClassLoader cl)
```
    Unregister metadata by class loader. This method unregisters all registered PersistenceCapable classes loaded by the specified class loader. Any attempt to get metadata for unregistered classes will result in a JDOFatalUserException.
    
    Parameters:
    
    cl - the class loader.
    
    Since:
    
    1.0.2
  - unregisterClass
```
public void unregisterClass(Class pcClass)
```
    Unregister metadata by class. This method unregisters the specified class. Any further attempt to get metadata for the specified class will result in a JDOFatalUserException.
    
    Parameters:
    
    pcClass - the PersistenceCapable class to be unregistered.
    
    Since:
    
    1.0.2
  - addRegisterClassListener
```
public void addRegisterClassListener(RegisterClassListener crl)
```
    Add the specified RegisterClassListener to the listener list.
    
    Parameters:
    
    crl - the listener to be added
  - removeRegisterClassListener
```
public void removeRegisterClassListener(RegisterClassListener crl)
```
    Remove the specified RegisterClassListener from the listener list.
    
    Parameters:
    
    crl - the listener to be removed
  - getRegisteredClasses
```
public Collection<Class> getRegisteredClasses()
```
    Returns a collection of class objects of the registered persistence-capable classes.
    
    Returns:
    
    registered persistence-capable classes
  - registerAuthorizedStateManagerClass
```
public static void registerAuthorizedStateManagerClass(Class smClass)
                                                throws SecurityException
```
    Register a class authorized to replaceStateManager. The caller of this method must be authorized for JDOPermission("setStateManager"). During replaceStateManager, a persistence-capable class will call the corresponding checkAuthorizedStateManager and the class of the instance of the parameter must have been registered.
    
    Parameters:
    
    smClass - a Class that is authorized for JDOPermission("setStateManager").
    
    Throws:
    
    SecurityException - if the caller is not authorized for JDOPermission("setStateManager").
    
    Since:
    
    1.0.1
  - registerAuthorizedStateManagerClasses
```
public static void registerAuthorizedStateManagerClasses(Collection smClasses)
                                                  throws SecurityException
```
    Register classes authorized to replaceStateManager. The caller of this method must be authorized for JDOPermission("setStateManager"). During replaceStateManager, a persistence-capable class will call the corresponding checkAuthorizedStateManager and the class of the instance of the parameter must have been registered.
    
    Parameters:
    
    smClasses - a Collection of Classes that are authorized for JDOPermission("setStateManager").
    
    Throws:
    
    SecurityException - if the caller is not authorized for JDOPermission("setStateManager").
    
    Since:
    
    1.0.1
  - registerDocumentBuilderFactory
```
public void registerDocumentBuilderFactory(DocumentBuilderFactory factory)
```
    Register a DocumentBuilderFactory instance for use in parsing the resource(s) META-INF/jdoconfig.xml. The default is governed by the semantics of DocumentBuilderFactory.newInstance().
    
    Parameters:
    
    factory - the DocumentBuilderFactory instance to use
    
    Since:
    
    2.1
  - getRegisteredDocumentBuilderFactory
```
public static DocumentBuilderFactory getRegisteredDocumentBuilderFactory()
```
    Return the registered instance of DocumentBuilderFactory.
    
    Returns:
    
    the DocumentBuilderFactory if registered; null otherwise
    
    Since:
    
    2.1
  - registerErrorHandler
```
public void registerErrorHandler(ErrorHandler handler)
```
    Register an ErrorHandler instance for use in parsing the resource(s) META-INF/jdoconfig.xml. The default is an ErrorHandler that throws on error or fatalError and ignores warnings.
    
    Parameters:
    
    handler - the ErrorHandler instance to use
    
    Since:
    
    2.1
  - getRegisteredErrorHandler
```
public static ErrorHandler getRegisteredErrorHandler()
```
    Return the registered instance of ErrorHandler.
    
    Returns:
    
    the registered ErrorHandler if registered; null otherwise
    
    Since:
    
    2.1
  - checkAuthorizedStateManager
```
public static void checkAuthorizedStateManager(StateManager sm)
```
    Check that the parameter instance is of a class that is authorized for JDOPermission("setStateManager"). This method is called by the replaceStateManager method in persistence-capable classes. A class that is passed as the parameter to replaceStateManager must be authorized for JDOPermission("setStateManager"). To improve performance, first the set of authorized classes is checked, and if not present, a regular permission check is made. The regular permission check requires that all callers on the stack, including the persistence-capable class itself, must be authorized for JDOPermission("setStateManager").
    
    Parameters:
    
    sm - an instance of StateManager whose class is to be checked.
    
    Since:
    
    1.0.1
  - checkAuthorizedStateManagerClass
```
public static void checkAuthorizedStateManagerClass(Class smClass)
```
    Check that the parameter instance is a class that is authorized for JDOPermission("setStateManager"). This method is called by the constructors of JDO Reference Implementation classes.
    
    Parameters:
    
    smClass - a Class to be checked for JDOPermission("setStateManager")
    
    Since:
    
    1.0.1
  - registerStringConstructor
```
public Object registerStringConstructor(Class cls,
                                        JDOImplHelper.StringConstructor sc)
```
    Register special StringConstructor instances. These instances are for constructing instances from String parameters where there is no String constructor for them.
    
    Parameters:
    
    cls - the class to register a StringConstructor for
    
    sc - the StringConstructor instance
    
    Returns:
    
    the previous StringConstructor registered for this class
  - construct
```
public static Object construct(String className,
                               String keyString)
```
    Construct an instance of the parameter class, using the keyString as an argument to the constructor. If the class has a StringConstructor instance registered, use it. If not, try to find a constructor for the class with a single String argument. Otherwise, throw a JDOUserException.
    
    Parameters:
    
    className - the name of the class
    
    keyString - the String parameter for the constructor
    
    Returns:
    
    the result of construction
  - registerDateFormat
```
public void registerDateFormat(DateFormat df)
```
    Register a DateFormat instance for use with constructing Date instances. The default is the default DateFormat instance. If the new instance implements SimpleDateFormat, get its pattern for error messages.
    
    Parameters:
    
    df - the DateFormat instance to use
    
    Since:
    
    2.0
  - addStateInterrogation
```
public void addStateInterrogation(StateInterrogation si)
```
    Add a StateInterrogation to the list. Create a new list in case there is an iterator open on the original list.
    
    Parameters:
    
    si - the StateInterrogation to add
  - removeStateInterrogation
```
public void removeStateInterrogation(StateInterrogation si)
```
    Remove a StateInterrogation from the list. Create a new list in case there is an iterator open on the original list.
    
    Parameters:
    
    si - the StateInterrogation to remove
  - nonBinaryCompatibleMakeDirty
```
public void nonBinaryCompatibleMakeDirty(Object pc,
                                         String fieldName)
```
    Mark a non-binary-compatible instance dirty. Delegate to all registered StateInterrogation instances until one of them handles the call.
    
    Parameters:
    
    pc - the instance to mark dirty
    
    fieldName - the field to mark dirty
  - nonBinaryCompatibleIs
```
public boolean nonBinaryCompatibleIs(Object pc,
                                     JDOImplHelper.StateInterrogationBooleanReturn sibr)
```
    Determine the state of a non-binary-compatible instance. Delegate to all registered StateInterrogation instances until one of them handles the call (returns a non-null Boolean with the answer). The caller provides the stateless "method object" that does the actual call to the StateInterrogation instance.
    
    Parameters:
    
    pc - the instance to be checked
    
    sibr - the method object that delegates to the non-binary-compatible implementation
    
    Returns:
    
    Boolean.TRUE if the instance satisfies the state interrogation; Boolean.FALSE if the instance does not satisfy the interrogation; or null if the implementation does not manage the class of the instance
  - nonBinaryCompatibleGet
```
public Object nonBinaryCompatibleGet(Object pc,
                                     JDOImplHelper.StateInterrogationObjectReturn sibr)
```
    Return an object associated with a non-binary-compatible instance. Delegate to all registered StateInterrogation instances until one of them handles the call (returns a non-null answer). The caller provides the stateless "method object" that does the actual call to the StateInterrogation instance.
    
    Parameters:
    
    pc - the instance whose associated object is needed
    
    sibr - the method object that delegates to the non-binary-compatible implementation
    
    Returns:
    
    the associated object or null if the implementation does not manage the class of the instance
  - assertOnlyKnownStandardProperties
```
public static void assertOnlyKnownStandardProperties(Map<?,?> properties)
```
    Examines the given map for keys beginning with the JDO standard prefix, Constants.JAVAX_JDO_PREFIX. If any property keys are found with that prefix but are unknown to this version of the JDO standard, a JDOUserException is thrown with a message indicating the unknown property. Keys that are not strings are ignored, as are string keys beginning with Constants.PROPERTY_PREFIX_INSTANCE_LIFECYCLE_LISTENER or not beginning with Constants.JAVAX_JDO_PREFIX.
    
    Parameters:
    
    properties - The properties to examine.
    
    Since:
    
    3.1
    
    See Also:
    
    Constants.JAVAX_JDO_PREFIX

Class JDOImplHelper

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

USER_CONFIGURABLE_STANDARD_PROPERTIES

Method Detail

getInstance

getFieldNames

getFieldTypes

getFieldFlags

getPersistenceCapableSuperclass

newInstance

newInstance

newObjectIdInstance

newObjectIdInstance

copyKeyFieldsToObjectId

copyKeyFieldsFromObjectId

registerClass

unregisterClasses

unregisterClass

addRegisterClassListener

removeRegisterClassListener

getRegisteredClasses

registerAuthorizedStateManagerClass

registerAuthorizedStateManagerClasses

registerDocumentBuilderFactory

getRegisteredDocumentBuilderFactory

registerErrorHandler

getRegisteredErrorHandler

checkAuthorizedStateManager

checkAuthorizedStateManagerClass

registerStringConstructor

construct

registerDateFormat

addStateInterrogation

removeStateInterrogation

nonBinaryCompatibleMakeDirty

nonBinaryCompatibleIs

nonBinaryCompatibleGet

assertOnlyKnownStandardProperties