- java.lang.Object
-
- javax.sql.rowset.spi.SyncProvider
-
public abstract class SyncProvider extends Object
The synchronization mechanism that provides reader/writer capabilities for disconnectedRowSet
objects. ASyncProvider
implementation is a class that extends theSyncProvider
abstract class.A
SyncProvider
implementation is identified by a unique ID, which is its fully qualified class name. This name must be registered with theSyncFactory
SPI, thus making the implementation available to allRowSet
implementations. The factory mechanism in the reference implementation uses this name to instantiate the implementation, which can then provide aRowSet
object with its reader (ajavax.sql.RowSetReader
object) and its writer (ajavax.sql.RowSetWriter
object).The Jdbc
RowSet
Implementations specification provides two reference implementations of theSyncProvider
abstract class:RIOptimisticProvider
andRIXMLProvider
. TheRIOptimisticProvider
can set anyRowSet
implementation with aRowSetReader
object and aRowSetWriter
object. However, only theRIXMLProvider
implementation can set anXmlReader
object and anXmlWriter
object. AWebRowSet
object uses theXmlReader
object to read data in XML format to populate itself with that data. It uses theXmlWriter
object to write itself to a stream orjava.io.Writer
object in XML format.1.0 Naming Convention for Implementations
As a guide to namingSyncProvider
implementations, the following should be noted:- The name for a
SyncProvider
implementation is its fully qualified class name. - It is recommended that vendors supply a
SyncProvider
implementation in a package namedproviders
.
For instance, if a vendor named Fred, Inc. offered a
SyncProvider
implementation, you could have the following:Vendor name: Fred, Inc. Domain name of vendor: com.fred Package name: com.fred.providers SyncProvider implementation class name: HighAvailabilityProvider Fully qualified class name of SyncProvider implementation: com.fred.providers.HighAvailabilityProvider
The following line of code uses the fully qualified name to register this implementation with the
SyncFactory
static instance.SyncFactory.registerProvider( "com.fred.providers.HighAvailabilityProvider");
The default
SyncProvider
object provided with the reference implementation uses the following name:com.sun.rowset.providers.RIOptimisticProvider
A vendor can register a
SyncProvider
implementation class name with Oracle Corporation by sending email to jdbc@sun.com. Oracle will maintain a database listing the availableSyncProvider
implementations for use with compliantRowSet
implementations. This database will be similar to the one already maintained to list available JDBC drivers.Vendors should refer to the reference implementation synchronization providers for additional guidance on how to implement a new
SyncProvider
implementation.2.0 How a RowSet Object Gets Its Provider
A disconnectedRowset
object may get access to aSyncProvider
object in one of the following two ways:- Using a constructor
CachedRowSet crs = new CachedRowSet( "com.fred.providers.HighAvailabilitySyncProvider");
- Using the
setSyncProvider
methodCachedRowSet crs = new CachedRowSet(); crs.setSyncProvider("com.fred.providers.HighAvailabilitySyncProvider");
By default, the reference implementations of the
RowSet
synchronization providers are always available to the Java platform. If no other pluggable synchronization providers have been correctly registered, theSyncFactory
will automatically generate an instance of the defaultSyncProvider
reference implementation. Thus, in the preceding code fragment, if no implementation namedcom.fred.providers.HighAvailabilitySyncProvider
has been registered with theSyncFactory
instance, crs will be assigned the default provider in the reference implementation, which iscom.sun.rowset.providers.RIOptimisticProvider
.3.0 Violations and Synchronization Issues
If an update between a disconnectedRowSet
object and a data source violates the original query or the underlying data source constraints, this will result in undefined behavior for all disconnectedRowSet
implementations and their designatedSyncProvider
implementations. Not defining the behavior when such violations occur offers greater flexibility for aSyncProvider
implementation to determine its own best course of action.A
SyncProvider
implementation may choose to implement a specific handler to handle a subset of query violations. However if an original query violation or a more general data source constraint violation is not handled by theSyncProvider
implementation, allSyncProvider
objects must throw aSyncProviderException
.4.0 Updatable SQL VIEWs
It is possible for any disconnected or connectedRowSet
object to be populated from an SQL query that is formulated originally from an SQLVIEW
. While in many cases it is possible for an update to be performed to an underlying view, such an update requires additional metadata, which may vary. TheSyncProvider
class provides two constants to indicate whether an implementation supports updating an SQLVIEW
.NONUPDATABLE_VIEW_SYNC
- Indicates that aSyncProvider
implementation does not support synchronization with an SQLVIEW
as the underlying source of data for theRowSet
object.UPDATABLE_VIEW_SYNC
- Indicates that aSyncProvider
implementation supports synchronization with an SQLVIEW
as the underlying source of data.
The default is for a
RowSet
object not to be updatable if it was populated with data from an SQLVIEW
.5.0 SyncProvider Constants
TheSyncProvider
class provides three sets of constants that are used as return values or parameters forSyncProvider
methods.SyncProvider
objects may be implemented to perform synchronization between aRowSet
object and its underlying data source with varying degrees of of care. The first group of constants indicate how synchronization is handled. For example,GRADE_NONE
indicates that aSyncProvider
object will not take any care to see what data is valid and will simply write theRowSet
data to the data source.GRADE_MODIFIED_AT_COMMIT
indicates that the provider will check only modified data for validity. Other grades check all data for validity or set locks when data is modified or loaded.- Constants to indicate the synchronization grade of a
SyncProvider
object- SyncProvider.GRADE_NONE
- SyncProvider.GRADE_MODIFIED_AT_COMMIT
- SyncProvider.GRADE_CHECK_ALL_AT_COMMIT
- SyncProvider.GRADE_LOCK_WHEN_MODIFIED
- SyncProvider.GRADE_LOCK_WHEN_LOADED
- Constants to indicate what locks are set on the data source
- SyncProvider.DATASOURCE_NO_LOCK
- SyncProvider.DATASOURCE_ROW_LOCK
- SyncProvider.DATASOURCE_TABLE_LOCK
- SyncProvider.DATASOURCE_DB_LOCK
- Constants to indicate whether a
SyncProvider
object can perform updates to an SQLVIEW
These constants are explained in the preceding section (4.0).- SyncProvider.UPDATABLE_VIEW_SYNC
- SyncProvider.NONUPDATABLE_VIEW_SYNC
- See Also:
SyncFactory
,SyncFactoryException
- The name for a
-
-
Field Summary
Fields Modifier and Type Field and Description static int
DATASOURCE_DB_LOCK
Indicates that a lock is placed on the entire data source that is the source of data for theRowSet
object that is using thisSyncProvider
object.static int
DATASOURCE_NO_LOCK
Indicates that no locks remain on the originating data source.static int
DATASOURCE_ROW_LOCK
Indicates that a lock is placed on the rows that are touched by the original SQL statement used to populate theRowSet
object that is using thisSyncProvider
object.static int
DATASOURCE_TABLE_LOCK
Indicates that a lock is placed on all tables that are touched by the original SQL statement used to populate theRowSet
object that is using thisSyncProvider
object.static int
GRADE_CHECK_ALL_AT_COMMIT
Indicates a high level optimistic synchronization grade with respect to the originating data source.static int
GRADE_CHECK_MODIFIED_AT_COMMIT
Indicates a low level optimistic synchronization grade with respect to the originating data source.static int
GRADE_LOCK_WHEN_LOADED
Indicates the most pessimistic synchronization grade with respect to the originating data source.static int
GRADE_LOCK_WHEN_MODIFIED
Indicates a pessimistic synchronization grade with respect to the originating data source.static int
GRADE_NONE
Indicates that no synchronization with the originating data source is provided.static int
NONUPDATABLE_VIEW_SYNC
Indicates that aSyncProvider
implementation does not support synchronization between aRowSet
object and the SQLVIEW
used to populate it.static int
UPDATABLE_VIEW_SYNC
Indicates that aSyncProvider
implementation supports synchronization between aRowSet
object and the SQLVIEW
used to populate it.
-
Constructor Summary
Constructors Constructor and Description SyncProvider()
Creates a defaultSyncProvider
object.
-
Method Summary
Methods Modifier and Type Method and Description abstract int
getDataSourceLock()
Returns the current data source lock severity level active in thisSyncProvider
implementation.abstract int
getProviderGrade()
Returns a constant indicating the grade of synchronization aRowSet
object can expect from thisSyncProvider
object.abstract String
getProviderID()
Returns the unique identifier for thisSyncProvider
object.abstract RowSetReader
getRowSetReader()
Returns ajavax.sql.RowSetReader
object, which can be used to populate aRowSet
object with data.abstract RowSetWriter
getRowSetWriter()
Returns ajavax.sql.RowSetWriter
object, which can be used to write aRowSet
object's data back to the underlying data source.abstract String
getVendor()
Returns the vendor name of thisSyncProvider
instanceabstract String
getVersion()
Returns the release version of thisSyncProvider
instance.abstract void
setDataSourceLock(int datasource_lock)
Sets a lock on the underlying data source at the level indicated by datasource_lock.abstract int
supportsUpdatableView()
Returns whether thisSyncProvider
implementation can perform synchronization between aRowSet
object and the SQLVIEW
in the data source from which theRowSet
object got its data.
-
-
-
Field Detail
-
GRADE_NONE
public static final int GRADE_NONE
Indicates that no synchronization with the originating data source is provided. ASyncProvider
implementation returning this grade will simply attempt to write updates in theRowSet
object to the underlying data source without checking the validity of any data.- See Also:
- Constant Field Values
-
GRADE_CHECK_MODIFIED_AT_COMMIT
public static final int GRADE_CHECK_MODIFIED_AT_COMMIT
Indicates a low level optimistic synchronization grade with respect to the originating data source. ASyncProvider
implementation returning this grade will check only rows that have changed.- See Also:
- Constant Field Values
-
GRADE_CHECK_ALL_AT_COMMIT
public static final int GRADE_CHECK_ALL_AT_COMMIT
Indicates a high level optimistic synchronization grade with respect to the originating data source. ASyncProvider
implementation returning this grade will check all rows, including rows that have not changed.- See Also:
- Constant Field Values
-
GRADE_LOCK_WHEN_MODIFIED
public static final int GRADE_LOCK_WHEN_MODIFIED
Indicates a pessimistic synchronization grade with respect to the originating data source. ASyncProvider
implementation returning this grade will lock the row in the originating data source.- See Also:
- Constant Field Values
-
GRADE_LOCK_WHEN_LOADED
public static final int GRADE_LOCK_WHEN_LOADED
Indicates the most pessimistic synchronization grade with respect to the originating data source. ASyncProvider
implementation returning this grade will lock the entire view and/or table affected by the original statement used to populate aRowSet
object.- See Also:
- Constant Field Values
-
DATASOURCE_NO_LOCK
public static final int DATASOURCE_NO_LOCK
Indicates that no locks remain on the originating data source. This is the default lock setting for allSyncProvider
implementations unless otherwise directed by aRowSet
object.- See Also:
- Constant Field Values
-
DATASOURCE_ROW_LOCK
public static final int DATASOURCE_ROW_LOCK
Indicates that a lock is placed on the rows that are touched by the original SQL statement used to populate theRowSet
object that is using thisSyncProvider
object.- See Also:
- Constant Field Values
-
DATASOURCE_TABLE_LOCK
public static final int DATASOURCE_TABLE_LOCK
Indicates that a lock is placed on all tables that are touched by the original SQL statement used to populate theRowSet
object that is using thisSyncProvider
object.- See Also:
- Constant Field Values
-
DATASOURCE_DB_LOCK
public static final int DATASOURCE_DB_LOCK
Indicates that a lock is placed on the entire data source that is the source of data for theRowSet
object that is using thisSyncProvider
object.- See Also:
- Constant Field Values
-
UPDATABLE_VIEW_SYNC
public static final int UPDATABLE_VIEW_SYNC
Indicates that aSyncProvider
implementation supports synchronization between aRowSet
object and the SQLVIEW
used to populate it.- See Also:
- Constant Field Values
-
NONUPDATABLE_VIEW_SYNC
public static final int NONUPDATABLE_VIEW_SYNC
Indicates that aSyncProvider
implementation does not support synchronization between aRowSet
object and the SQLVIEW
used to populate it.- See Also:
- Constant Field Values
-
-
Method Detail
-
getProviderID
public abstract String getProviderID()
Returns the unique identifier for thisSyncProvider
object.- Returns:
- a
String
object with the fully qualified class name of thisSyncProvider
object
-
getRowSetReader
public abstract RowSetReader getRowSetReader()
Returns ajavax.sql.RowSetReader
object, which can be used to populate aRowSet
object with data.- Returns:
- a
javax.sql.RowSetReader
object
-
getRowSetWriter
public abstract RowSetWriter getRowSetWriter()
Returns ajavax.sql.RowSetWriter
object, which can be used to write aRowSet
object's data back to the underlying data source.- Returns:
- a
javax.sql.RowSetWriter
object
-
getProviderGrade
public abstract int getProviderGrade()
Returns a constant indicating the grade of synchronization aRowSet
object can expect from thisSyncProvider
object.- Returns:
- an int that is one of the following constants: SyncProvider.GRADE_NONE, SyncProvider.GRADE_CHECK_MODIFIED_AT_COMMIT, SyncProvider.GRADE_CHECK_ALL_AT_COMMIT, SyncProvider.GRADE_LOCK_WHEN_MODIFIED, SyncProvider.GRADE_LOCK_WHEN_LOADED
-
setDataSourceLock
public abstract void setDataSourceLock(int datasource_lock) throws SyncProviderException
Sets a lock on the underlying data source at the level indicated by datasource_lock. This should cause theSyncProvider
to adjust its behavior by increasing or decreasing the level of optimism it provides for a successful synchronization.- Parameters:
datasource_lock
- one of the following constants indicating the severity level of data source lock required:SyncProvider.DATASOURCE_NO_LOCK, SyncProvider.DATASOURCE_ROW_LOCK, SyncProvider.DATASOURCE_TABLE_LOCK, SyncProvider.DATASOURCE_DB_LOCK,
- Throws:
SyncProviderException
- if an unsupported data source locking level is set.- See Also:
getDataSourceLock()
-
getDataSourceLock
public abstract int getDataSourceLock() throws SyncProviderException
Returns the current data source lock severity level active in thisSyncProvider
implementation.- Returns:
- a constant indicating the current level of data source lock
active in this
SyncProvider
object; one of the following:SyncProvider.DATASOURCE_NO_LOCK, SyncProvider.DATASOURCE_ROW_LOCK, SyncProvider.DATASOURCE_TABLE_LOCK, SyncProvider.DATASOURCE_DB_LOCK
- Throws:
SyncProviderExceptiom
- if an error occurs determining the data source locking level.SyncProviderException
- See Also:
setDataSourceLock(int)
-
supportsUpdatableView
public abstract int supportsUpdatableView()
Returns whether thisSyncProvider
implementation can perform synchronization between aRowSet
object and the SQLVIEW
in the data source from which theRowSet
object got its data.- Returns:
- an
int
saying whether thisSyncProvider
object supports updating an SQLVIEW
; one of the following: SyncProvider.UPDATABLE_VIEW_SYNC, SyncProvider.NONUPDATABLE_VIEW_SYNC
-
getVersion
public abstract String getVersion()
Returns the release version of thisSyncProvider
instance.- Returns:
- a
String
detailing the release version of theSyncProvider
implementation
-
getVendor
public abstract String getVendor()
Returns the vendor name of thisSyncProvider
instance- Returns:
- a
String
detailing the vendor name of thisSyncProvider
implementation
-
-
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