org.exolab.castor.persist
Class ClassMolder

java.lang.Object
  extended by org.exolab.castor.persist.ClassMolder

public class ClassMolder
extends java.lang.Object

ClassMolder is a binder for one type of data object and its Persistence. For example, when ClassMolder is asked to load an object, it acquires values from Persistence and binds it into an target object. It also resolves relations via TransactionContext and bind related object into an target object.

Beside loading, ClassMolder is also repsonsible for storing, removing, creating an object to and from a persistence storage, as well as reverting an object to previous state.

Each instance of ClassMolder deals with exactly one persistable type, interacts with one instance of Persistent and belongs to one LockEngine.

Author:
Thomas Yip, Bruce Snyder

Field Summary
(package private)  boolean _isKeyGenUsed
          Is a key kenerator used for the base class?
(package private)  boolean resolversHaveBeenReset
           
 
Constructor Summary
ClassMolder(DatingService ds, MappingLoader loader, LockEngine lock, ClassDescriptor clsDesc, Persistence persist)
          Creates an instance of this class.
 
Method Summary
(package private)  void addDependent(ClassMolder dep)
          Mutator method to add a dependent ClassMolder
(package private)  void addExtendent(ClassMolder ext)
          Mutator method to add a extent ClassMolder
 java.lang.Object create(TransactionContext tx, OID oid, DepositBox locker, java.lang.Object object)
          Create an object of the base class with specified identity into the persistence storage.
 void delete(TransactionContext tx, OID oid)
          Delete an object of the base type from the persistence storage.
 void expireCache(TransactionContext tx, ObjectLock locker)
          Inspect the fields stored in the object passed as an argument for contained objects.
 AccessMode getAccessMode(AccessMode txMode)
          Get the effective accessMode of the the base type
 java.lang.Object getActualIdentity(java.lang.ClassLoader loader, java.lang.Object o)
          Get the identity from a object of the base type
 java.lang.Object getActualIdentity(TransactionContext tx, java.lang.Object o)
          Get the identity from a object of the base type
 int getCacheParam()
          Return the preferred LRU cache capacity for caching object of this type
 java.lang.String getCacheType()
          Return the preferred LRU cache mechanism for caching object of this type
 CallbackInterceptor getCallback()
          Get the callback interceptor of the base type
 ClassMolder getDepends()
          Get the depends class' ClassMolder
 ClassMolder getExtends()
          Get the extends class' ClassMolder
 FieldMolder[] getFields()
          Get the FieldMolder of the fields of the base type, except the identity fields.
 java.lang.Object getIdentity(TransactionContext tx, java.lang.Object o)
          Get the identity from a object of the base type If object isn't persistent and key generator is used, returns null
 FieldMolder[] getIds()
          Get the FieldMolders of the identity fields
 java.lang.Class getJavaClass(java.lang.ClassLoader loader)
          Get the base class of this ClassMolder given a ClassLoader
 LockEngine getLockEngine()
          Get the LockEngine which this ClassMolder belongs to.
 java.lang.String getName()
          Get the fully qualified name of the base type of this ClassMolder
 Persistence getPersistence()
          Get the Persisetence of the base type
 int getPriority()
          Determines the create priority of the data object class represented by this ClassMolder.
 boolean isAssignableFrom(java.lang.Class cls)
          check if the current ClassModlder is assignable from the class instance.
 boolean isDefaultIdentity(java.lang.Object identity)
          Test if the specified identity is the default value of the type.
 boolean isDependent()
          Return true if the base type of this ClassMolder is an dependent class.
 boolean isKeyGeneratorUsed()
          Return true if a key generator is used for the base type of this ClassMolder
 boolean isKeyGenUsed()
          Return true if a key generator is used for the base type of this ClassMolder
 java.lang.Object load(TransactionContext tx, OID oid, DepositBox locker, ProposedObject proposedObject, AccessMode suggestedAccessMode)
          Load an object with specified identity from the persistent storage.
 java.lang.Object load(TransactionContext tx, OID oid, DepositBox locker, ProposedObject proposedObject, AccessMode suggestedAccessMode, QueryResults results)
           
 void markCreate(TransactionContext tx, OID oid, DepositBox locker, java.lang.Object object)
          Walk the object model and mark object that should be created.
 void markDelete(TransactionContext tx, OID oid, DepositBox locker, java.lang.Object object)
          Prepare to delete an object with the specified identity.
 java.lang.Object newInstance(java.lang.ClassLoader loader)
          Return a new instance of the base class with the provided ClassLoader object
 boolean preStore(TransactionContext tx, OID oid, DepositBox locker, java.lang.Object object, int timeout)
          Check the object for modification.
 boolean removeRelation(TransactionContext tx, java.lang.Object object, ClassMolder relatedMolder, java.lang.Object relatedObject)
          Remove the reference of a related object from an object of the base class.
 void resetResolvers()
           
 void revertObject(TransactionContext tx, OID oid, DepositBox locker, java.lang.Object object)
          Revert the object back to the state of begining of the transaction If the object is loaded, it will be revert as it was loaded.
(package private)  void setDepends(ClassMolder dep)
          Mutator method to set the depends ClassMolder
(package private)  void setExtends(ClassMolder ext)
          Mutator method to set the extends ClassMolder
 void setFieldsNull(java.lang.Object object)
          Set all persistence fields of object of the base type to null.
 void setIdentity(TransactionContext tx, java.lang.Object object, java.lang.Object identity)
          Set the identity into an object
 void setPersistence(Persistence persist)
          Mutator method to set the PersistenceEngine of
 void store(TransactionContext tx, OID oid, DepositBox locker, java.lang.Object object)
          Store a data object into the persistent storage of the base class of this ClassMolder.
 java.lang.String toString()
           
 boolean update(TransactionContext tx, OID oid, DepositBox locker, java.lang.Object object, AccessMode suggestedAccessMode)
          Update the object which loaded or created in the other transaction to the persistent storage.
 void updateCache(TransactionContext tx, OID oid, DepositBox locker, java.lang.Object object)
          Update the dirty checking cache.
 void writeLock(TransactionContext tx, OID oid, DepositBox locker, java.lang.Object object)
          Acquire a write lock on an object of the base type with the specified identity from the persistence storage.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

_isKeyGenUsed

boolean _isKeyGenUsed
Is a key kenerator used for the base class?


resolversHaveBeenReset

boolean resolversHaveBeenReset
Constructor Detail

ClassMolder

ClassMolder(DatingService ds,
            MappingLoader loader,
            LockEngine lock,
            ClassDescriptor clsDesc,
            Persistence persist)
      throws java.lang.ClassNotFoundException,
             MappingException
Creates an instance of this class.

Parameters:
ds - is the helper class for resolving depends and extends relationship among all the ClassMolder in the same LockEngine.
loader - the mapping loader.
lock - the lock engine.
clsDesc - the classDescriptor for the base class.
persist - the Persistence for the base class.
Throws:
java.lang.ClassNotFoundException - If a class cannot be loaded.
MappingException - if an error occured with analysing the mapping information.
Method Detail

removeRelation

public boolean removeRelation(TransactionContext tx,
                              java.lang.Object object,
                              ClassMolder relatedMolder,
                              java.lang.Object relatedObject)
Remove the reference of a related object from an object of the base class.

If the related object is PersistanceCapable, the field will be set null. If the related object is a Collection, then the related object will be removed from the Collection.

If any changed occured, transactionContext.markModified will be called, to indicate the object is modified.

It method will iterate thur all of the object's field and try to remove all the occurrence.

Parameters:
tx - the TransactionContext of the transaction in action
object - the target object of the base type of this ClassMolder
relatedMolder - the ClassMolder of the related object to be removed from the object
relatedObject - the object to be removed

getPriority

public int getPriority()
Determines the create priority of the data object class represented by this ClassMolder. Concpetually, this method determines the order of which data object should be created. Priority of zero means the object can be created without depending on other data object. This method should only be called after DatingService is closed.


load

public java.lang.Object load(TransactionContext tx,
                             OID oid,
                             DepositBox locker,
                             ProposedObject proposedObject,
                             AccessMode suggestedAccessMode)
                      throws ObjectNotFoundException,
                             PersistenceException
Load an object with specified identity from the persistent storage.

Parameters:
tx - the TransactionContext in action
oid - the object identity of the desired object
locker - the DepositBox of the object which is used to store the dirty checking cache of the object.
suggestedAccessMode - the acessMode for the object
Returns:
the object stamp for the object in the persistent storage
Throws:
ObjectNotFoundException
PersistenceException

load

public java.lang.Object load(TransactionContext tx,
                             OID oid,
                             DepositBox locker,
                             ProposedObject proposedObject,
                             AccessMode suggestedAccessMode,
                             QueryResults results)
                      throws ObjectNotFoundException,
                             PersistenceException
Throws:
ObjectNotFoundException
PersistenceException

create

public java.lang.Object create(TransactionContext tx,
                               OID oid,
                               DepositBox locker,
                               java.lang.Object object)
                        throws DuplicateIdentityException,
                               PersistenceException
Create an object of the base class with specified identity into the persistence storage.

Parameters:
tx - transaction in action
oid - the object identity of the object to be created.
locker - the dirty checking cache of the object
object - the object to be created
Returns:
the identity of the object
Throws:
DuplicateIdentityException
PersistenceException

markCreate

public void markCreate(TransactionContext tx,
                       OID oid,
                       DepositBox locker,
                       java.lang.Object object)
                throws DuplicateIdentityException,
                       PersistenceException
Walk the object model and mark object that should be created.

Parameters:
tx - transaction in action
oid - the object identity of the object to be created.
locker - the dirty checking cache of the object
object - the object to be created
Throws:
DuplicateIdentityException
PersistenceException

preStore

public boolean preStore(TransactionContext tx,
                        OID oid,
                        DepositBox locker,
                        java.lang.Object object,
                        int timeout)
                 throws PersistenceException
Check the object for modification. If dpendent object is dereferenced, it method will remove the object thru the transaction. If an related object is dereferenced, it method will make sure the formally object will be dereferenced from the other side as well. This method is called in prepare (for commit) state of the transaction. This method indicates if the object needed to be persist or cache should be update using TransactionContext.markDelete.

Parameters:
tx - transaction in action
oid - the object identity of the object
locker - the dirty check cache for the object
object - the data object to be checked
timeout - timeout of updating the lock if needed
Returns:
true if the object is modified
Throws:
PersistenceException

store

public void store(TransactionContext tx,
                  OID oid,
                  DepositBox locker,
                  java.lang.Object object)
           throws DuplicateIdentityException,
                  PersistenceException,
                  ObjectModifiedException,
                  ObjectDeletedException
Store a data object into the persistent storage of the base class of this ClassMolder.

Parameters:
tx - Transaction in action
oid - the object identity of the stored object
locker - the dirty check cache of the object
object - the object to be stored
Throws:
DuplicateIdentityException
PersistenceException
ObjectModifiedException
ObjectDeletedException

update

public boolean update(TransactionContext tx,
                      OID oid,
                      DepositBox locker,
                      java.lang.Object object,
                      AccessMode suggestedAccessMode)
               throws PersistenceException,
                      ObjectModifiedException
Update the object which loaded or created in the other transaction to the persistent storage.

Parameters:
tx - Transaction in action
oid - the object identity of the stored object
locker - the dirty check cache of the object
object - the object to be stored
Returns:
boolean true if the updating object should be created
Throws:
PersistenceException
ObjectModifiedException

updateCache

public void updateCache(TransactionContext tx,
                        OID oid,
                        DepositBox locker,
                        java.lang.Object object)
Update the dirty checking cache. This method is called after a transaction completed successfully.

Parameters:
tx - - transaction in action
oid - - object's identity of the target object
locker - - the dirty checking cache of the target object
object - - the target object

delete

public void delete(TransactionContext tx,
                   OID oid)
            throws PersistenceException
Delete an object of the base type from the persistence storage. All object to be deleted by this method will be markDelete before it method is called.

Parameters:
tx - - transaction in action
oid - - the object identity of the target object
Throws:
PersistenceException

markDelete

public void markDelete(TransactionContext tx,
                       OID oid,
                       DepositBox locker,
                       java.lang.Object object)
                throws ObjectNotFoundException,
                       PersistenceException
Prepare to delete an object with the specified identity. If any sub-object should be deleted along with the target object, it should be deleted by this method.

Parameters:
tx - - transaction in action
oid - - object's identity of the target object
locker - - the dirty checking cache of the target object
object - - the target object
Throws:
ObjectNotFoundException
PersistenceException

revertObject

public void revertObject(TransactionContext tx,
                         OID oid,
                         DepositBox locker,
                         java.lang.Object object)
                  throws PersistenceException
Revert the object back to the state of begining of the transaction If the object is loaded, it will be revert as it was loaded. If the object is created, it will be revert as it was just created.

Parameters:
tx - - transaction in action
oid - - the object identity of the target object
locker - - the dirty checking cache of the target object
object - - the target object
Throws:
PersistenceException

writeLock

public void writeLock(TransactionContext tx,
                      OID oid,
                      DepositBox locker,
                      java.lang.Object object)
               throws PersistenceException
Acquire a write lock on an object of the base type with the specified identity from the persistence storage.

Parameters:
tx - - Transaction in action
oid - - the object identity of the target object
locker - - the dirty checking cache of the object
object - - the target object
Throws:
PersistenceException

newInstance

public java.lang.Object newInstance(java.lang.ClassLoader loader)
                             throws java.lang.InstantiationException,
                                    java.lang.IllegalAccessException,
                                    java.lang.ClassNotFoundException
Return a new instance of the base class with the provided ClassLoader object

Parameters:
loader - the ClassLoader object to use to create a new object
Returns:
Object the object reprenseted by this ClassMolder, and instanciated with the provided ClassLoader instance.
Throws:
java.lang.ClassNotFoundException
java.lang.IllegalAccessException
java.lang.InstantiationException

getAccessMode

public AccessMode getAccessMode(AccessMode txMode)
Get the effective accessMode of the the base type

Parameters:
txMode - - the default transaction accessMode
Returns:
the effective acessMode of the base type

getCallback

public CallbackInterceptor getCallback()
Get the callback interceptor of the base type


isDefaultIdentity

public boolean isDefaultIdentity(java.lang.Object identity)
Test if the specified identity is the default value of the type.


getIdentity

public java.lang.Object getIdentity(TransactionContext tx,
                                    java.lang.Object o)
Get the identity from a object of the base type If object isn't persistent and key generator is used, returns null

Parameters:
tx - the transaction context
o - - object of the base type
Returns:
return an Object[] which contains the identity of the object

getActualIdentity

public java.lang.Object getActualIdentity(TransactionContext tx,
                                          java.lang.Object o)
Get the identity from a object of the base type

Parameters:
tx - the transaction context
o - - object of the base type
Returns:
return an Object[] which contains the identity of the object

getActualIdentity

public java.lang.Object getActualIdentity(java.lang.ClassLoader loader,
                                          java.lang.Object o)
Get the identity from a object of the base type

Parameters:
loader - the current class loader
o - - object of the base type
Returns:
return an Object[] which contains the identity of the object

setIdentity

public void setIdentity(TransactionContext tx,
                        java.lang.Object object,
                        java.lang.Object identity)
                 throws PersistenceException
Set the identity into an object

Parameters:
tx - the transaction context
object - the object to set the identity
identity - the new identity for the object
Throws:
PersistenceException

getPersistence

public Persistence getPersistence()
Get the Persisetence of the base type


setPersistence

public void setPersistence(Persistence persist)
Mutator method to set the PersistenceEngine of


getJavaClass

public java.lang.Class getJavaClass(java.lang.ClassLoader loader)
Get the base class of this ClassMolder given a ClassLoader

Parameters:
loader - the classloader
Returns:
the Class instance

isAssignableFrom

public boolean isAssignableFrom(java.lang.Class cls)
check if the current ClassModlder is assignable from the class instance.

Parameters:
cls - the Class to check the assignation
Returns:
true if assignable

getName

public java.lang.String getName()
Get the fully qualified name of the base type of this ClassMolder


getFields

public FieldMolder[] getFields()
Get the FieldMolder of the fields of the base type, except the identity fields.


getIds

public FieldMolder[] getIds()
Get the FieldMolders of the identity fields


getExtends

public ClassMolder getExtends()
Get the extends class' ClassMolder


getDepends

public ClassMolder getDepends()
Get the depends class' ClassMolder


getLockEngine

public LockEngine getLockEngine()
Get the LockEngine which this ClassMolder belongs to.


getCacheType

public java.lang.String getCacheType()
Return the preferred LRU cache mechanism for caching object of this type


getCacheParam

public int getCacheParam()
Return the preferred LRU cache capacity for caching object of this type


isDependent

public boolean isDependent()
Return true if the base type of this ClassMolder is an dependent class.


setFieldsNull

public void setFieldsNull(java.lang.Object object)
Set all persistence fields of object of the base type to null.

Parameters:
object - - target object

addExtendent

void addExtendent(ClassMolder ext)
Mutator method to add a extent ClassMolder


addDependent

void addDependent(ClassMolder dep)
Mutator method to add a dependent ClassMolder


setExtends

void setExtends(ClassMolder ext)
Mutator method to set the extends ClassMolder


setDepends

void setDepends(ClassMolder dep)
Mutator method to set the depends ClassMolder


toString

public java.lang.String toString()
Overrides:
toString in class java.lang.Object

isKeyGenUsed

public boolean isKeyGenUsed()
Return true if a key generator is used for the base type of this ClassMolder


isKeyGeneratorUsed

public boolean isKeyGeneratorUsed()
Return true if a key generator is used for the base type of this ClassMolder


expireCache

public void expireCache(TransactionContext tx,
                        ObjectLock locker)
                 throws PersistenceException
Inspect the fields stored in the object passed as an argument for contained objects. Request an expireCache for each contained object.

Parameters:
tx - The org.exolab.castor.persist.TransactionContext
locker - The object that contains the fields to be inspected
Throws:
PersistenceException

resetResolvers

public void resetResolvers()


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