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package javax.sql.rowset.spi;
import javax.sql.*;
/**
* The synchronization mechanism that provides reader/writer capabilities for
* disconnected <code>RowSet</code> objects.
* A <code>SyncProvider</code> implementation is a class that extends the
* <code>SyncProvider</code> abstract class.
* <P>
* A <code>SyncProvider</code> implementation is
* identified by a unique ID, which is its fully qualified class name.
* This name must be registered with the
* <code>SyncFactory</code> SPI, thus making the implementation available to
* all <code>RowSet</code> implementations.
* The factory mechanism in the reference implementation uses this name to instantiate
* the implementation, which can then provide a <code>RowSet</code> object with its
* reader (a <code>javax.sql.RowSetReader</code> object) and its writer (a
* <code>javax.sql.RowSetWriter</code> object).
* <P>
* The Jdbc <code>RowSet</code> Implementations specification provides two
* reference implementations of the <code>SyncProvider</code> abstract class:
* <code>RIOptimisticProvider</code> and <code>RIXMLProvider</code>.
* The <code>RIOptimisticProvider</code> can set any <code>RowSet</code>
* implementation with a <code>RowSetReader</code> object and a
* <code>RowSetWriter</code> object. However, only the <code>RIXMLProvider</code>
* implementation can set an <code>XmlReader</code> object and an
* <code>XmlWriter</code> object. A <code>WebRowSet</code> object uses the
* <code>XmlReader</code> object to read data in XML format to populate itself with that
* data. It uses the <code>XmlWriter</code> object to write itself to a stream or
* <code>java.io.Writer</code> object in XML format.
* <P>
* <h3>1.0 Naming Convention for Implementations</h3>
* As a guide to naming <code>SyncProvider</code>
* implementations, the following should be noted:
* <UL>
* <li>The name for a <code>SyncProvider</code> implementation
* is its fully qualified class name.
* <li>It is recommended that vendors supply a
* <code>SyncProvider</code> implementation in a package named <code>providers</code>.
* </UL>
* <p>
* For instance, if a vendor named Fred, Inc. offered a
* <code>SyncProvider</code> implementation, you could have the following:
* <PRE>
* 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
* </PRE>
* <P>
* The following line of code uses the fully qualified name to register
* this implementation with the <code>SyncFactory</code> static instance.
* <PRE>
* SyncFactory.registerProvider(
* "com.fred.providers.HighAvailabilityProvider");
* </PRE>
* <P>
* The default <code>SyncProvider</code> object provided with the reference
* implementation uses the following name:
* <pre>
* com.sun.rowset.providers.RIOptimisticProvider
* </pre>
* <p>
* A vendor can register a <code>SyncProvider</code> implementation class name
* with Oracle Corporation by sending email to jdbc@sun.com.
* Oracle will maintain a database listing the
* available <code>SyncProvider</code> implementations for use with compliant
* <code>RowSet</code> implementations. This database will be similar to the
* one already maintained to list available JDBC drivers.
* <P>
* Vendors should refer to the reference implementation synchronization
* providers for additional guidance on how to implement a new
* <code>SyncProvider</code> implementation.
*
* <h3>2.0 How a <code>RowSet</code> Object Gets Its Provider</h3>
*
* A disconnected <code>Rowset</code> object may get access to a
* <code>SyncProvider</code> object in one of the following two ways:
* <UL>
* <LI>Using a constructor<BR>
* <PRE>
* CachedRowSet crs = new CachedRowSet(
* "com.fred.providers.HighAvailabilitySyncProvider");
* </PRE>
* <LI>Using the <code>setSyncProvider</code> method
* <PRE>
* CachedRowSet crs = new CachedRowSet();
* crs.setSyncProvider("com.fred.providers.HighAvailabilitySyncProvider");
* </PRE>
* </UL>
* <p>
* By default, the reference implementations of the <code>RowSet</code> synchronization
* providers are always available to the Java platform.
* If no other pluggable synchronization providers have been correctly
* registered, the <code>SyncFactory</code> will automatically generate
* an instance of the default <code>SyncProvider</code> reference implementation.
* Thus, in the preceding code fragment, if no implementation named
* <code>com.fred.providers.HighAvailabilitySyncProvider</code> has been
* registered with the <code>SyncFactory</code> instance, <i>crs</i> will be
* assigned the default provider in the reference implementation, which is
* <code>com.sun.rowset.providers.RIOptimisticProvider</code>.
* <p>
* <h3>3.0 Violations and Synchronization Issues</h3>
* If an update between a disconnected <code>RowSet</code> object
* and a data source violates
* the original query or the underlying data source constraints, this will
* result in undefined behavior for all disconnected <code>RowSet</code> implementations
* and their designated <code>SyncProvider</code> implementations.
* Not defining the behavior when such violations occur offers greater flexibility
* for a <code>SyncProvider</code>
* implementation to determine its own best course of action.
* <p>
* A <code>SyncProvider</code> 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 the <code>SyncProvider</code> implementation,
* all <code>SyncProvider</code>
* objects must throw a <code>SyncProviderException</code>.
* <p>
* <h3>4.0 Updatable SQL VIEWs</h3>
* It is possible for any disconnected or connected <code>RowSet</code> object to be populated
* from an SQL query that is formulated originally from an SQL <code>VIEW</code>.
* 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.
* The <code>SyncProvider</code> class provides two constants to indicate whether
* an implementation supports updating an SQL <code>VIEW</code>.
* <ul>
* <li><code><b>NONUPDATABLE_VIEW_SYNC</b></code> - Indicates that a <code>SyncProvider</code>
* implementation does not support synchronization with an SQL <code>VIEW</code> as the
* underlying source of data for the <code>RowSet</code> object.
* <li><code><b>UPDATABLE_VIEW_SYNC</b></code> - Indicates that a
* <code>SyncProvider</code> implementation
* supports synchronization with an SQL <code>VIEW</code> as the underlying source
* of data.
* </ul>
* <P>
* The default is for a <code>RowSet</code> object not to be updatable if it was
* populated with data from an SQL <code>VIEW</code>.
* <P>
* <h3>5.0 <code>SyncProvider</code> Constants</h3>
* The <code>SyncProvider</code> class provides three sets of constants that
* are used as return values or parameters for <code>SyncProvider</code> methods.
* <code>SyncProvider</code> objects may be implemented to perform synchronization
* between a <code>RowSet</code> object and its underlying data source with varying
* degrees of of care. The first group of constants indicate how synchronization
* is handled. For example, <code>GRADE_NONE</code> indicates that a
* <code>SyncProvider</code> object will not take any care to see what data is
* valid and will simply write the <code>RowSet</code> data to the data source.
* <code>GRADE_MODIFIED_AT_COMMIT</code> 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.
* <OL>
* <LI>Constants to indicate the synchronization grade of a
* <code>SyncProvider</code> object
* <UL>
* <LI>SyncProvider.GRADE_NONE
* <LI>SyncProvider.GRADE_MODIFIED_AT_COMMIT
* <LI>SyncProvider.GRADE_CHECK_ALL_AT_COMMIT
* <LI>SyncProvider.GRADE_LOCK_WHEN_MODIFIED
* <LI>SyncProvider.GRADE_LOCK_WHEN_LOADED
* </UL>
* <LI>Constants to indicate what locks are set on the data source
* <UL>
* <LI>SyncProvider.DATASOURCE_NO_LOCK
* <LI>SyncProvider.DATASOURCE_ROW_LOCK
* <LI>SyncProvider.DATASOURCE_TABLE_LOCK
* <LI>SyncProvider.DATASOURCE_DB_LOCK
* </UL>
* <LI>Constants to indicate whether a <code>SyncProvider</code> object can
* perform updates to an SQL <code>VIEW</code> <BR>
* These constants are explained in the preceding section (4.0).
* <UL>
* <LI>SyncProvider.UPDATABLE_VIEW_SYNC
* <LI>SyncProvider.NONUPDATABLE_VIEW_SYNC
* </UL>
* </OL>
*
* @author Jonathan Bruce
* @see javax.sql.rowset.spi.SyncFactory
* @see javax.sql.rowset.spi.SyncFactoryException
*/
public abstract class SyncProvider {
/**
* Creates a default <code>SyncProvider</code> object.
*/
public SyncProvider() {
}
/**
* Returns the unique identifier for this <code>SyncProvider</code> object.
*
* @return a <code>String</code> object with the fully qualified class name of
* this <code>SyncProvider</code> object
*/
public abstract String getProviderID();
/**
* Returns a <code>javax.sql.RowSetReader</code> object, which can be used to
* populate a <code>RowSet</code> object with data.
*
* @return a <code>javax.sql.RowSetReader</code> object
*/
public abstract RowSetReader getRowSetReader();
/**
* Returns a <code>javax.sql.RowSetWriter</code> object, which can be
* used to write a <code>RowSet</code> object's data back to the
* underlying data source.
*
* @return a <code>javax.sql.RowSetWriter</code> object
*/
public abstract RowSetWriter getRowSetWriter();
/**
* Returns a constant indicating the
* grade of synchronization a <code>RowSet</code> object can expect from
* this <code>SyncProvider</code> object.
*
* @return 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
*/
public abstract int getProviderGrade();
/**
* Sets a lock on the underlying data source at the level indicated by
* <i>datasource_lock</i>. This should cause the
* <code>SyncProvider</code> to adjust its behavior by increasing or
* decreasing the level of optimism it provides for a successful
* synchronization.
*
* @param datasource_lock one of the following constants indicating the severity
* level of data source lock required:
* <pre>
* SyncProvider.DATASOURCE_NO_LOCK,
* SyncProvider.DATASOURCE_ROW_LOCK,
* SyncProvider.DATASOURCE_TABLE_LOCK,
* SyncProvider.DATASOURCE_DB_LOCK,
* </pre>
* @throws SyncProviderException if an unsupported data source locking level
* is set.
* @see #getDataSourceLock
*/
public abstract void setDataSourceLock(int datasource_lock)
throws SyncProviderException;
/**
* Returns the current data source lock severity level active in this
* <code>SyncProvider</code> implementation.
*
* @return a constant indicating the current level of data source lock
* active in this <code>SyncProvider</code> object;
* one of the following:
* <pre>
* SyncProvider.DATASOURCE_NO_LOCK,
* SyncProvider.DATASOURCE_ROW_LOCK,
* SyncProvider.DATASOURCE_TABLE_LOCK,
* SyncProvider.DATASOURCE_DB_LOCK
* </pre>
* @throws SyncProviderExceptiom if an error occurs determining the data
* source locking level.
* @see #setDataSourceLock
*/
public abstract int getDataSourceLock()
throws SyncProviderException;
/**
* Returns whether this <code>SyncProvider</code> implementation
* can perform synchronization between a <code>RowSet</code> object
* and the SQL <code>VIEW</code> in the data source from which
* the <code>RowSet</code> object got its data.
*
* @return an <code>int</code> saying whether this <code>SyncProvider</code>
* object supports updating an SQL <code>VIEW</code>; one of the
* following:
* SyncProvider.UPDATABLE_VIEW_SYNC,
* SyncProvider.NONUPDATABLE_VIEW_SYNC
*/
public abstract int supportsUpdatableView();
/**
* Returns the release version of this <code>SyncProvider</code> instance.
*
* @return a <code>String</code> detailing the release version of the
* <code>SyncProvider</code> implementation
*/
public abstract String getVersion();
/**
* Returns the vendor name of this <code>SyncProvider</code> instance
*
* @return a <code>String</code> detailing the vendor name of this
* <code>SyncProvider</code> implementation
*/
public abstract String getVendor();
/*
* Standard description of synchronization grades that a SyncProvider
* could provide.
*/
/**
* Indicates that no synchronization with the originating data source is
* provided. A <code>SyncProvider</code>
* implementation returning this grade will simply attempt to write
* updates in the <code>RowSet</code> object to the underlying data
* source without checking the validity of any data.
*
*/
public static final int GRADE_NONE = 1;
/**
* Indicates a low level optimistic synchronization grade with
* respect to the originating data source.
*
* A <code>SyncProvider</code> implementation
* returning this grade will check only rows that have changed.
*
*/
public static final int GRADE_CHECK_MODIFIED_AT_COMMIT = 2;
/**
* Indicates a high level optimistic synchronization grade with
* respect to the originating data source.
*
* A <code>SyncProvider</code> implementation
* returning this grade will check all rows, including rows that have not
* changed.
*/
public static final int GRADE_CHECK_ALL_AT_COMMIT = 3;
/**
* Indicates a pessimistic synchronization grade with
* respect to the originating data source.
*
* A <code>SyncProvider</code>
* implementation returning this grade will lock the row in the originating
* data source.
*/
public static final int GRADE_LOCK_WHEN_MODIFIED = 4;
/**
* Indicates the most pessimistic synchronization grade with
* respect to the originating
* data source. A <code>SyncProvider</code>
* implementation returning this grade will lock the entire view and/or
* table affected by the original statement used to populate a
* <code>RowSet</code> object.
*/
public static final int GRADE_LOCK_WHEN_LOADED = 5;
/**
* Indicates that no locks remain on the originating data source. This is the default
* lock setting for all <code>SyncProvider</code> implementations unless
* otherwise directed by a <code>RowSet</code> object.
*/
public static final int DATASOURCE_NO_LOCK = 1;
/**
* Indicates that a lock is placed on the rows that are touched by the original
* SQL statement used to populate the <code>RowSet</code> object
* that is using this <code>SyncProvider</code> object.
*/
public static final int DATASOURCE_ROW_LOCK = 2;
/**
* Indicates that a lock is placed on all tables that are touched by the original
* SQL statement used to populate the <code>RowSet</code> object
* that is using this <code>SyncProvider</code> object.
*/
public static final int DATASOURCE_TABLE_LOCK = 3;
/**
* Indicates that a lock is placed on the entire data source that is the source of
* data for the <code>RowSet</code> object
* that is using this <code>SyncProvider</code> object.
*/
public static final int DATASOURCE_DB_LOCK = 4;
/**
* Indicates that a <code>SyncProvider</code> implementation
* supports synchronization between a <code>RowSet</code> object and
* the SQL <code>VIEW</code> used to populate it.
*/
public static final int UPDATABLE_VIEW_SYNC = 5;
/**
* Indicates that a <code>SyncProvider</code> implementation
* does <B>not</B> support synchronization between a <code>RowSet</code>
* object and the SQL <code>VIEW</code> used to populate it.
*/
public static final int NONUPDATABLE_VIEW_SYNC = 6;
}