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	/*
	* Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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.
	*
	* <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>.
	*
	* <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>.
	*
	* <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>.
	*
	* <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 SyncProviderException 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;
	}

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