Package com.sun.jdo.api.persistence.support

Class JDOHelper

  • public class JDOHelper
extends Object
    An utility class for querying PersistenceCapable objects.

    • Constructor Detail

      • JDOHelper

        public JDOHelper()

    • Method Detail

      • getPersistenceManager

        public static PersistenceManager getPersistenceManager​(Object obj)
        Returns the associated PersistenceManager of an object if there is one. For transactional and persistent objects, their associated PersistenceManager is returned. For transient objects, null is returned.
        Parameters:
        obj - an Object
        Returns:
        the PersistenceManager associated with the object; null otherwise
        See Also:
        PersistenceCapable.jdoGetPersistenceManager()

      • makeDirty

        public static void makeDirty​(Object obj,
                             String fieldName)
        Explicitly marks a field of an object as dirty if the object is persistent and transactional. Normally, PersistenceCapable classes are able to detect changes made to their fields. However, if a reference to an Array is given to a method outside the class, and the Array is modified, then the persistent object is not aware of the change. This method allows the application to notify the object that a change was made to a field. For transient objects, this method does nothing.
        Parameters:
        obj - an object
        fieldName - the name of the object's field to be marked dirty
        See Also:
        PersistenceCapable.jdoMakeDirty(String fieldName)

      • getObjectId

        public static Object getObjectId​(Object obj)
        Returns a copy of the JDO identity associated with an object. Persistent objects of PersistenceCapable classes have a JDO identity managed by the PersistenceManager. This method returns a copy of the ObjectId that represents the JDO identity of a persistent object. For transient objects, null is returned.

        The ObjectId may be serialized and later restored, and used with a PersistenceManager from the same JDO implementation to locate a persistent object with the same data store identity. If the JDO identity is managed by the application, then the ObjectId may be used with a PersistenceManager from any JDO implementation that supports the PersistenceCapable class. If the JDO identity is not managed by the application or the data store, then the ObjectId returned is only valid within the current transaction.

        Parameters:
        obj - an Object
        Returns:
        a copy of the ObjectId of a persistent object; null if the object is transient
        See Also:
        PersistenceCapable.jdoGetObjectId(), PersistenceManager.getObjectId(Object obj), PersistenceManager.getObjectById(Object oid)

      • isDirty

        public static boolean isDirty​(Object obj)
        Tests whether an object is dirty. If the object have been modified, deleted, or newly made persistent in the current transaction, true is returned. For transient objects, false is returned.
        Parameters:
        obj - an Object
        Returns:
        true if the object has been modified in the current transaction; false otherwise.
        See Also:
        PersistenceCapable.jdoIsDirty(), PersistenceCapable.jdoMakeDirty(String fieldName)

      • isTransactional

        public static boolean isTransactional​(Object obj)
        Tests whether an object is transactional. For objects that respect transaction boundaries, true is returned. These objects include transient objects made transactional as a result of being the target of a makeTransactional method call; newly made persistent or deleted persistent objects; persistent objects read in data store transactions; and persistent objects modified in optimistic transactions. For non-transactional objects, false is returned.
        Parameters:
        obj - an Object
        Returns:
        true if the object is transactional; false otherwise.
        See Also:
        PersistenceCapable.jdoIsTransactional()

      • isNew

        public static boolean isNew​(Object obj)
        Tests whether the object has been newly made persistent. For objects that have been made persistent in the current transaction, true is returned. For transient or objects, false is returned.
        Parameters:
        obj - an Object
        Returns:
        true if the object was made persistent in the current transaction; false otherwise.
        See Also:
        PersistenceCapable.jdoIsNew(), PersistenceManager.makePersistent(Object obj)

      • isDeleted

        public static boolean isDeleted​(Object obj)
        Tests whether the object has been deleted. For objects that have been deleted in the current transaction, true is returned. For transient objects, false is returned.
        Parameters:
        obj - an Object
        Returns:
        true if the object was deleted in the current transaction; false otherwise.
        See Also:
        PersistenceCapable.jdoIsDeleted(), PersistenceManager.deletePersistent(Object obj)

      • printObject

        public static String printObject​(Object o)
        Prints the object. If object is not NULL and is not deleted, calls toString() method on the object. Does not allow to access fields of the deleted object