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Oracle9i Business Components for Java API Reference Oracle9i Jdeveloper (9.0.4) B10391-01 | ||||||||||
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This interface provides access to rows. This interface is implemented by View rows and Entity rows. Custom application logic can use this interface to access database table rows independently of the implementation of the underlying row. For example, assume that a custom application is written to perform batch style inserts into a database table. Such an application can reference the Row interface for row access instead of accessing instances of EntityImpl
or ViewRowImpl
directly. This design would allow changes in a row's implementation (Entity row or View row) without necessitating changes in the application logic.
In addition to providing a base type for View row and Entity row access, this interface provides tier-independent access to rows. Consequently, custom application logic can reference the interface on both the client and middle tiers of a three-tier application.
Note in an application running in the three-tier configuration, Entity rows are not marshalled to the client tier. The client tier has access only to View rows and not Entity rows. Of course, in the middle tier, the business logic has full access to both View rows and Entity rows. This interface should not be implemented by a custom application.
RowImpl
, EntityImpl
, ViewRowImpl
Field Summary | |
static int |
REFRESH_CONTAINEES REFRESH_... constants are used as refresh mode flags to be passed into . |
static int |
REFRESH_REMOVE_NEW_ROWS REFRESH_... constants are used as refresh mode flags to be passed into . |
static int |
REFRESH_UNDO_CHANGES REFRESH_... constants are used as refresh mode flags to be passed into . |
static int |
REFRESH_WITH_DB_FORGET_CHANGES REFRESH_... constants are used as refresh mode flags to be passed into . |
static int |
REFRESH_WITH_DB_ONLY_IF_UNCHANGED REFRESH_... constants are used as refresh mode flags to be passed into . |
static byte |
STATUS_INITIALIZED Indicates that the row is newly created and no setAttribute has been called on it yet. |
static byte |
STATUS_NEW Indicates that the Row is newly created and this Row's consistuent entities have been added to the transaction. |
Fields inherited from interface oracle.jbo.XMLInterface |
XML_IGNORE_DEPTH_COUNT, XML_OPT_ALL_ROWS, XML_OPT_ASSOC_CONSISTENT, XML_OPT_CHANGES_ONLY, XML_OPT_LIMIT_RANGE |
Method Summary | |
Key |
getKey() Returns the row's key. |
StructureDef |
getStructureDef() Returns the structure of the row. |
boolean |
isAttributeUpdateable(int index) Tests if an attribute is updateable. |
void |
lock() Locks the row(s) in the database table. |
void |
refresh(int refreshMode) Refreshes the row's attributes with values from database. |
void |
remove() Removes the row from the database table. |
void |
removeFromCollection() Removes the row from the collection. |
void |
setNewRowState(byte state) Sets a new unposted row, created in this transaction, to either STATUS_NEW or STATUS_INITIALIZED mode. |
void |
validate() Validates the row. |
Methods inherited from interface oracle.jbo.AttributeList |
getAttribute, getAttribute, getAttributeCount, getAttributeIndexOf, getAttributeNames, getAttributeValues, setAttribute, setAttribute |
Methods inherited from interface oracle.jbo.XMLInterface |
readXML, readXML, writeXML, writeXML, writeXML, writeXML |
Field Detail |
public static final byte STATUS_INITIALIZED
public static final byte STATUS_NEW
public static final int REFRESH_WITH_DB_FORGET_CHANGES
REFRESH_...
constants are used as refresh mode flags to be passed into refresh(int)
.
REFRESH_WITH_DB_FORGET_CHANGES
forgets edits that the current user made to the row. The row data is refreshed from database. The latest data from database replaces data in the row regardless of whether the row as modified or not.
If the current user had called ApplicationModule#postChanges()
REFRESH_WITH_DB_FORGET_CHANGES
will pick up the data that he himself wrote through his call to postChanges()
.
If REFRESH_REMOVE_NEW_ROWS
is not specified, REFRESH_WITH_DB_FORGET_CHANGES
puts a new row back to blank. If REFRESH_REMOVE_NEW_ROWS
is specified, the new row is removed.
public static final int REFRESH_WITH_DB_ONLY_IF_UNCHANGED
REFRESH_...
constants are used as refresh mode flags to be passed into refresh(int)
.
REFRESH_WITH_DB_ONLY_IF_UNCHANGED
works just like REFRESH_WITH_DB_FORGET_CHANGES
for unmodified rows, i.e., the row is refreshed with attribute values from the database. If a row was already modified by this transaction, the row is not refreshed.
If locking mode is pessimistic, the fact that you (this user) were able to change the data means that you were able to lock the row and that you got the latest data.
When using this refresh mode, if the locking mode is optimistic, the framework could bring the latest data for unmodified attributes and merge them into the row, while retaining changed attributes as is. However, this could lead to data integrity problems. Thus, for consistency sake and data integrity, we leave the row alone if it was modified even for optimistic locking mode.
If REFRESH_REMOVE_NEW_ROWS
is not specified, calling refresh with this mode will be a no-op (treated just like a modified row). If REFRESH_REMOVE_NEW_ROWS
is specified, the new row is removed.
public static final int REFRESH_UNDO_CHANGES
REFRESH_...
constants are used as refresh mode flags to be passed into refresh(int)
.
REFRESH_UNDO_CHANGES
works just like REFRESH_WITH_DB_FORGET_CHANGES
for unmodified rows, i.e., the row is refreshed with attribute values from the database.
For a modified row, this mode refreshes the row with attribute values at the beginning of this transaction. This mode will back out changes that have been posted to database through postChanges()
, but not yet committed. Suppose a row's attribute value was modified from 'A' to 'B' and 'B' is posted. Suppose further the user changes 'B' to 'C' (after the post). Calling refresh(int)
with this mode will restore the attribute value to 'A'.
Out on database, the attribute value is still 'B'. However, the row is marked as modified, so that when the changes are posted later 'A' will replace 'B' out on database.
If REFRESH_REMOVE_NEW_ROWS
is not specified, REFRESH_UNDO_CHANGES
puts a new row back to blank. If REFRESH_REMOVE_NEW_ROWS
is specified, the new is removed.
public static final int REFRESH_REMOVE_NEW_ROWS
REFRESH_...
constants are used as refresh mode flags to be passed into refresh(int)
.
REFRESH_REMOVE_NEW_ROWS
is a bit-wise flag that can be OR'ed with other REFRESH_...
constants.
If REFRESH_REMOVE_NEW_ROWS
is specified, refresh(int)
will remove new rows.
public static final int REFRESH_CONTAINEES
REFRESH_...
constants are used as refresh mode flags to be passed into refresh(int)
.
REFRESH_CONTAINEES
is a bit-wise flag that can be OR'ed with other REFRESH_...
constants.
REFRESH_CONTAINEES
causes an Entity row to call refresh(int)
on its containees (children) with the same refresh mode (if this Entity row is a master is composition association).
Method Detail |
public Key getKey()
public void validate()
ValidationException
- if a validation error is detected.EntityImpl.validate()
, ViewRowImpl.validate()
public void lock()
RowNotFoundException
- if the row to be locked no longer exists in the database table. The row was probably deleted by another transaction (and transaction committed).DeadEntityAccessException
- if the row to locked is one that has already been deleted.TooManyObjectsException
- to service the lock request, a SELECT statement is issued against the database table using this row's primary key value. Normally, only one row with matching primary key should be found in the database. If more than one row with the given PK is found, this represents a data inconsistency problem in the table. In that case, this exception is thrown.RowInconsistentException
- after the row is locked in the database table, BC4J retrieves the latest data values from the table. A check is made to see if the row had been changed by another transaction (and committed). If so, this exception is thrown.AlreadyLockedException
- if the row is already locked by another transaction.DMLException
- if the SELECT statement to lock the row is not accepted by the DBMS. Make sure that the statement generated for the Entity Object is correct.public void remove()
JboException
- a runtime exception, if an exception occurs during access.public void removeFromCollection()
This method differs from
in that it simply removes the row from the collection. It does not remove the underlying Entity row(s) or database row(s).remove()
public boolean isAttributeUpdateable(int index)
index
- the index of the attribute.true
if the row is marked UPDATEABLE
, or if the row is marked UPDATEABLE_WHILE_NEW
and the current row is new.public StructureDef getStructureDef()
public void refresh(int refreshMode)
refreshMode
should be a combination of REFRESH_...
. See REFRESH_...
constants for further information.refreshMode
- the refresh mode.public void setNewRowState(byte state)
This method should be used to create a row and then to mark it temporary (STATUS_INITIALIZED) so that an app can use the created Row to fill UIs like Table UIs with valid default values for rows. Then when the Row values are updated, UIs should once again call this method to turn the Row into new (STATUS_NEW) state before any setAttribute calls on the Row, so that the changes are validated and posted.
When a created row is in STATUS_NEW (by default) state and this method is called to turn the row in to STATUS_INITIALIZED, all updateable entities that this row comprises of, de=registers themselves from their respective transaction and validation managers. Assocation and ViewLink finders will not find/include these rows. Only the collection into which this row was inserted into will contain a reference to this row and when that collection is re-executed this row cannot be reached via the framework. To include this row again an app should call this method again with STATUS_NEW as the method-argument
When this row is in STATUS_INITIALIZED state and this method is called with STATUS_NEW state then, this new row is added back into it's relevant transaction and validation manager and will then participate in validation, transaction cycles.
Note that incase of composition if a master/detail hierarchy is being created with the intention of making them temporary (STATUS_INITIALIZED) then the logic should be: Create Master row, insert Master row into a collection, create Detail row insert detail row into a relevant collection, make detail row initialized, create/insert/change-to-initialized more detail rows and at the end set the master row as initialized.
state
- This could be STATUS_NEW or STATUS_INITIALIZED.
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Oracle9i Business Components for Java API Reference Oracle9i Jdeveloper (9.0.4) B10391-01 | ||||||||||
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