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package com.sun.rowset.providers;

import com.sun.rowset.JdbcRowSetResourceBundle;

import java.io.IOException;

import java.sql.*;

import javax.sql.*;

import javax.sql.rowset.spi.*;

/**

 * A reference implementation of a JDBC RowSet synchronization provider

 * with the ability to read and write rowsets in well formed XML using the

 * standard WebRowSet schema.

 *

 * <h3>1.0 Background</h3>

 * This synchronization provider is registered with the

 * <code>SyncFactory</code> by default as the

 * <code>com.sun.rowset.providers.RIXMLProvider</code>.

 * <P>

 * A <code>WebRowSet</code> object uses an <code>RIXMLProvider</code> implementation

 * to read an XML data source or to write itself in XML format using the

 * <code>WebRowSet</code> XML schema definition available at

 * <pre>

 *     <a href="http://java.sun.com/xml/ns/jdbc/webrowset.xsd">http://java.sun.com/xml/ns/jdbc/webrowset.xsd</a>

 * </pre>

 * The <code>RIXMLProvider</code> implementation has a synchronization level of

 * GRADE_NONE, which means that it does no checking at all for conflicts.  It

 * simply writes a <code>WebRowSet</code> object to a file.

 * <h3>2.0 Usage</h3>

 * A <code>WebRowSet</code> implementation is created with an <code>RIXMLProvider</code>

 * by default.

 * <pre>

 *     WebRowSet wrs = new FooWebRowSetImpl();

 * </pre>

 * The <code>SyncFactory</code> always provides an instance of

 * <code>RIOptimisticProvider</code> when no provider is specified,

 * but the implementation of the default constructor for <code>WebRowSet</code> sets the

 * provider to be the <code>RIXMLProvider</code> implementation.  Therefore,

 * the following line of code is executed behind the scenes as part of the

 * implementation of the default constructor.

 * <pre>

 *     wrs.setSyncProvider("com.sun.rowset.providers.RIXMLProvider");

 * </pre>

 * See the standard <code>RowSet</code> reference implementations in the

 * <code>com.sun.rowset</code> package for more details.

 *

 * @author  Jonathan Bruce

 * @see javax.sql.rowset.spi.SyncProvider

 * @see javax.sql.rowset.spi.SyncProviderException

 * @see javax.sql.rowset.spi.SyncFactory

 * @see javax.sql.rowset.spi.SyncFactoryException

 */

public final class RIXMLProvider extends SyncProvider {

    /**

     * The unique provider identifier.

     */

    private String providerID = "com.sun.rowset.providers.RIXMLProvider";

    /**

     * The vendor name of this SyncProvider implementation.

     */

    /**

     * The version number of this SyncProvider implementation.

     */

    private String versionNumber = "1.0";

    private JdbcRowSetResourceBundle resBundle;

    private XmlReader xmlReader;

    private XmlWriter xmlWriter;

    /**

     * This provider is available to all JDBC <code>RowSet</code> implementations as the

     * default persistence provider.

     */

    public RIXMLProvider() {

        providerID = this.getClass().getName();

        try {

           resBundle = JdbcRowSetResourceBundle.getJdbcRowSetResourceBundle();

        } catch(IOException ioe) {

            throw new RuntimeException(ioe);

        }

    }

    /**

     * Returns <code>"javax.sql.rowset.providers.RIXMLProvider"</code>, which is

     * the fully qualified class name of this provider implementation.

     *

     * @return a <code>String</code> object with the fully specified class name of

     *           this <code>RIOptimisticProvider</code> implementation

     */

    public String getProviderID() {

        return providerID;

    }

    // additional methods that sit on top of reader/writer methods back to

    // original datasource. Allow XML state to be written out and in

    /**

     * Sets this <code>WebRowSet</code> object's reader to the given

     * <code>XmlReader</code> object.

     *

     * @throws SQLException if a database access error occurs

     */

    public void setXmlReader(XmlReader reader) throws SQLException {

        xmlReader = reader;

    }

    /**

     * Sets this <code>WebRowSet</code> object's writer to the given

     * <code>XmlWriter</code> object.

     *

     * @throws SQLException if a database access error occurs

     */

    public void setXmlWriter(XmlWriter writer) throws SQLException {

        xmlWriter = writer;

    }

    /**

     * Retrieves the reader that this <code>WebRowSet</code> object

     * will call when its <code>readXml</code> method is called.

     *

     * @return the <code>XmlReader</code> object for this SyncProvider

     * @throws SQLException if a database access error occurs

     */

    public XmlReader getXmlReader() throws SQLException {

        return xmlReader;

    }

    /**

     * Retrieves the writer that this <code>WebRowSet</code> object

     * will call when its <code>writeXml</code> method is called.

     *

     * @return the <code>XmlWriter</code> for this SyncProvider

     * @throws SQLException if a database access error occurs

     */

    public XmlWriter getXmlWriter() throws SQLException {

        return xmlWriter;

    }

    /**

     * Returns the <code>SyncProvider</code> grade of syncrhonization that

     * <code>RowSet</code> object instances can expect when using this

     * implementation. As this implementation provides no synchonization

     * facilities to the XML data source, the lowest grade is returned.

     *

     * @return the <code>SyncProvider</code> syncronization grade of this

     *     provider; must be one of the following constants:

     *       <PRE>

     *          SyncProvider.GRADE_NONE,

     *          SyncProvider.GRADE_MODIFIED_AT_COMMIT,

     *          SyncProvider.GRADE_CHECK_ALL_AT_COMMIT,

     *          SyncProvider.GRADE_LOCK_WHEN_MODIFIED,

     *          SyncProvider.GRADE_LOCK_WHEN_LOADED

     *       </PRE>

     *

     */

    public int getProviderGrade() {

        return SyncProvider.GRADE_NONE;

    }

    /**

     * Returns the default UPDATABLE_VIEW behavior of this reader

     *

     */

    public int supportsUpdatableView() {

        return SyncProvider.NONUPDATABLE_VIEW_SYNC;

    }

    /**

     * Returns the default DATASOURCE_LOCK behavior of this reader

     */

    public int getDataSourceLock() throws SyncProviderException {

        return SyncProvider.DATASOURCE_NO_LOCK;

    }

    /**

     * Throws an unsupported operation exception as this method does

     * function with non-locking XML data sources.

     */

    public void setDataSourceLock(int lock) throws SyncProviderException {

        throw new UnsupportedOperationException(resBundle.handleGetObject("rixml.unsupp").toString());

    }

    /**

     * Returns a null object as RowSetWriters are not returned by this SyncProvider

     */

    public RowSetWriter getRowSetWriter() {

        return null;

    }

    /**

     * Returns a null object as RowSetWriter objects are not returned by this

     * SyncProvider

     */

    public RowSetReader getRowSetReader() {

        return null;

    }

  /**

     * Returns the release version ID of the Reference Implementation Optimistic

     * Synchronization Provider.

     *

     * @return the <code>String</code> detailing the version number of this SyncProvider

     */

    public String getVersion() {

        return this.versionNumber;

    }

    /**

     * Returns the vendor name of the Reference Implemntation Optimistic

     * Syncchronication Provider

     *

     * @return the <code>String</code> detailing the vendor name of this

     *      SyncProvider

     */

    public String getVendor() {

        return this.vendorName;

    }

}