| author | chegar |
| Mon, 18 Aug 2014 10:59:36 +0100 | |
| changeset 25991 | e48157b42439 |
| parent 25976 | jdk/src/share/classes/javax/sql/rowset/spi/package.html@4de01a56e3ee |
| parent 25859 | jdk/src/share/classes/javax/sql/rowset/spi/package.html@3317bb8137f4 |
| child 32210 | 958d823579c3 |
| permissions | -rw-r--r-- |
| 2 | 1 |
<!DOCTYPE doctype PUBLIC "-//w3c//dtd html 4.0 transitional//en"> |
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<html> |
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<head> |
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<meta http-equiv="Content-Type" |
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content="text/html; charset=iso-8859-1"> |
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<meta name="GENERATOR" |
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content="Mozilla/4.79 [en] (Windows NT 5.0; U) [Netscape]"> |
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<!-- |
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Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved. |
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DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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This code is free software; you can redistribute it and/or modify it |
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under the terms of the GNU General Public License version 2 only, as |
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published by the Free Software Foundation. Oracle designates this |
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particular file as subject to the "Classpath" exception as provided |
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by Oracle in the LICENSE file that accompanied this code. |
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This code is distributed in the hope that it will be useful, but WITHOUT |
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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version 2 for more details (a copy is included in the LICENSE file that |
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accompanied this code). |
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You should have received a copy of the GNU General Public License version |
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2 along with this work; if not, write to the Free Software Foundation, |
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Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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or visit www.oracle.com if you need additional information or have any |
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questions. |
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--> |
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<title>javax.sql.rowset.spi</title> |
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</head> |
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<body bgcolor="#ffffff"> |
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The standard classes and interfaces that a third party vendor has to |
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use in its implementation of a synchronization provider. These classes and |
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interfaces are referred to as the Service Provider Interface (SPI). A vendor may |
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have its implementation included on the JDBC web page that lists available |
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<code>SyncProvider</code> implementations by sending email to <code>jdbc@sun.com</code>. |
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Doing this helps make developers aware of the implementation. To make it possible |
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for a <code>RowSet</code> object to use an implementation, the vendor must register |
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it with the <code>SyncFactory</code> singleton. (See the class comment for |
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<code>SyncProvider</code> for a full explanation of the registration process and |
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the naming convention to be used.) |
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<h2>Table of Contents</h2> |
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<ul> |
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<li><a href="#pkgspec">1.0 Package Specification</a> |
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<li><a href="#arch">2.0 Service Provider Architecture</a> |
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<li><a href="#impl">3.0 Implementer's Guide</a> |
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<li><a href="#resolving">4.0 Resolving Synchronization Conflicts</a> |
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<li><a href="#relspec">5.0 Related Specifications</a> |
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<li><a href="#reldocs">6.0 Related Documentation</a> |
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</ul> |
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<h3><a name="pkgspec">1.0 Package Specification</a></h3> |
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<P> |
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The following classes and interfaces make up the <code>javax.sql.rowset.spi</code> |
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package: |
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<UL> |
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<LI><code>SyncFactory</code> |
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<LI><code>SyncProvider</code> |
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<LI><code>SyncFactoryException</code> |
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<LI><code>SyncProviderException</code> |
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<LI><code>SyncResolver</code> |
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<LI><code>XmlReader</code> |
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<LI><code>XmlWriter</code> |
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<LI><code>TransactionalWriter</code> |
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</UL> |
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The following interfaces, in the <code>javax.sql</code> package, are also part of the SPI: |
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<UL> |
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<LI><code>RowSetReader</code> |
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<LI><code>RowSetWriter</code> |
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</UL> |
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<P> |
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A <code>SyncProvider</code> implementation provides a disconnected <code>RowSet</code> |
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object with the mechanisms for reading data into it and for writing data that has been |
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modified in it |
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back to the underlying data source. A <i>reader</i>, a <code>RowSetReader</code> or |
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<code>XMLReader</code> object, reads data into a <code>RowSet</code> object when the |
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<code>CachedRowSet</code> methods <code>execute</code> or <code>populate</code> |
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are called. A <i>writer</i>, a <code>RowSetWriter</code> or <code>XMLWriter</code> |
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object, writes changes back to the underlying data source when the |
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<code>CachedRowSet</code> method <code>acceptChanges</code> is called. |
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<P> |
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The process of writing changes in a <code>RowSet</code> object to its data source |
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is known as <i>synchronization</i>. The <code>SyncProvider</code> implementation that a |
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<code>RowSet</code> object is using determines the level of synchronization that the |
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<code>RowSet</code> object's writer uses. The various levels of synchronization are |
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referred to as <i>grades</i>. |
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<P> |
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The lower grades of synchronization are |
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known as <i>optimistic</i> concurrency levels because they optimistically |
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assume that there will be no conflicts or very few conflicts. A conflict exists when |
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the same data modified in the <code>RowSet</code> object has also been modified |
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in the data source. Using the optimistic concurrency model means that if there |
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is a conflict, modifications to either the data source or the <code>RowSet</code> |
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object will be lost. |
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<P> |
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Higher grades of synchronization are called <i>pessimistic</i> because they assume |
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that others will be accessing the data source and making modifications. These |
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grades set varying levels of locks to increase the chances that no conflicts |
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occur. |
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<P> |
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The lowest level of synchronization is simply writing any changes made to the |
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<code>RowSet</code> object to its underlying data source. The writer does |
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nothing to check for conflicts. |
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If there is a conflict and the data |
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source values are overwritten, the changes other parties have made by to the data |
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source are lost. |
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<P> |
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The <code>RIXMLProvider</code> implementation uses the lowest level |
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of synchronization and just writes <code>RowSet</code> changes to the data source. |
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This is true because typically XML data sources do not enable transaction |
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techniques for maintaining the integrity of data. However, specific standards |
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groups have considered offering XML-based synchronization. For details, see |
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<PRE> |
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<a href="http://www.syncml.org">http://www.syncml.org</a> |
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</PRE> |
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<P> |
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For the next level up, the |
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writer checks to see if there are any conflicts, and if there are, |
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it does not write anything to the data source. The problem with this concurrency |
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level is that if another party has modified the corresponding data in the data source |
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since the <code>RowSet</code> object got its data, |
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the changes made to the <code>RowSet</code> object are lost. The |
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<code>RIOptimisticProvider</code> implementation uses this level of synchronization. |
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<P> |
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At higher levels of synchronization, referred to as pessimistic concurrency, |
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the writer take steps to avoid conflicts by setting locks. Setting locks |
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can vary from setting a lock on a single row to setting a lock on a table |
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or the entire data source. The level of synchronization is therefore a tradeoff |
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between the ability of users to access the data source concurrently and the ability |
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of the writer to keep the data in the <code>RowSet</code> object and its data source |
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synchronized. |
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<P> |
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It is a requirement that all disconnected <code>RowSet</code> objects |
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(<code>CachedRowSet</code>, <code>FilteredRowSet</code>, <code>JoinRowSet</code>, |
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and <code>WebRowSet</code> objects) obtain their <code>SyncProvider</code> objects |
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from the <code>SyncFactory</code> mechanism. |
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<P> |
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The reference implementation (RI) provides two synchronization providers. |
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<UL> |
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<LI><b><tt>RIOptimisticProvider</tt></b> <br> |
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The default provider that the <code>SyncFactory</code> instance will |
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supply to a disconnected <code>RowSet</code> object when no provider |
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implementation is specified.<BR> |
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This synchronization provider uses an optimistic concurrency model, |
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assuming that there will be few conflicts among users |
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who are accessing the same data in a database. It avoids |
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using locks; rather, it checks to see if there is a conflict |
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before trying to synchronize the <code>RowSet</code> object and the |
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data source. If there is a conflict, it does nothing, meaning that |
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changes to the <code>RowSet</code> object are not persisted to the data |
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source. |
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<LI><B><tt>RIXMLProvider</tt></B> <BR> |
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A synchronization provider that can be used with a |
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<code>WebRowSet</code> object, which is a rowset that can be written |
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in XML format or read from XML format. The |
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<code>RIXMLProvider</code> implementation does no checking at all for |
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conflicts and simply writes any updated data in the |
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<code>WebRowSet</code> object to the underlying data source. |
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<code>WebRowSet</code> objects use this provider when they are |
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dealing with XML data. |
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</UL> |
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These <code>SyncProvider</code> implementations |
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are bundled with the reference implementation, which makes them always available to |
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<code>RowSet</code> implementations. |
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<code>SyncProvider</code> implementations make themselves available by being |
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registered with the <code>SyncFactory</code> singleton. When a <code>RowSet</code> |
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object requests a provider, by specifying it in the constructor or as an argument to the |
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<code>CachedRowSet</code> method <code>setSyncProvider</code>, |
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the <code>SyncFactory</code> singleton |
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checks to see if the requested provider has been registered with it. |
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If it has, the <code>SyncFactory</code> creates an instance of it and passes it to the |
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requesting <code>RowSet</code> object. |
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If the <code>SyncProvider</code> implementation that is specified has not been registered, |
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the <code>SyncFactory</code> singleton causes a <code>SyncFactoryException</code> object |
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to be thrown. If no provider is specified, |
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the <code>SyncFactory</code> singleton will create an instance of the default |
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provider implementation, <code>RIOptimisticProvider</code>, |
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and pass it to the requesting <code>RowSet</code> object. |
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<P> |
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If a <code>WebRowSet</code> object does not specify a provider in its constructor, the |
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<code>SyncFactory</code> will give it an instance of <code>RIOptimisticProvider</code>. |
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However, the constructor for <code>WebRowSet</code> is implemented to set the provider |
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to the <code>RIXMLProvider</code>, which reads and writes a <code>RowSet</code> object |
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in XML format. |
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<P> |
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See the <a href="SyncProvider.html">SyncProvider</a> class |
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specification for further details. |
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<p> |
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Vendors may develop a <tt>SyncProvider</tt> implementation with any one of the possible |
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levels of synchronization, thus giving <code>RowSet</code> objects a choice of |
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synchronization mechanisms. A vendor can make its implementation available by |
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registering the fully qualified class name with Oracle Corporation at |
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<code>jdbc@sun.com</code>. This process is discussed in further detail below. |
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<h3><a name="arch">2.0 Service Provider Interface Architecture</a></h3> |
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<b>2.1 Overview</b> |
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<p> |
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The Service Provider Interface provides a pluggable mechanism by which |
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<code>SyncProvider</code> implementations can be registered and then generated when |
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required. The lazy reference mechanism employed by the <code>SyncFactory</code> limits |
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unnecessary resource consumption by not creating an instance until it is |
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required by a disconnected |
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<code>RowSet</code> object. The <code>SyncFactory</code> class also provides |
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a standard API to configure logging options and streams that <b>may</b> be provided |
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by a particular <code>SyncProvider</code> implementation. |
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<p> |
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<b>2.2 Registering with the <code>SyncFactory</code></b> |
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<p> |
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A third party <code>SyncProvider</code> implementation must be registered with the |
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<code>SyncFactory</code> in order for a disconnected <code>RowSet</code> object |
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to obtain it and thereby use its <code>javax.sql.RowSetReader</code> and |
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<code>javax.sql.RowSetWriter</code> |
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implementations. The following registration mechanisms are available to all |
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<code>SyncProvider</code> implementations: |
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<ul> |
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<li><b>System properties</b> - Properties set at the command line. These |
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properties are set at run time and apply system-wide per invocation of the Java |
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application. See the section <a href="#reldocs">"Related Documentation"</a> |
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further related information. |
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<li><b>Property Files</b> - Properties specified in a standard property file. |
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This can be specified using a System Property or by modifying a standard |
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property file located in the platform run-time. The |
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reference implementation of this technology includes a standard property |
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file than can be edited to add additional <code>SyncProvider</code> objects. |
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<li><b>JNDI Context</b> - Available providers can be registered on a JNDI |
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context. The <tt>SyncFactory</tt> will attempt to load <tt>SyncProvider</tt> |
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objects bound to the context and register them with the factory. This |
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context must be supplied to the <code>SyncFactory</code> for the mechanism to |
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function correctly. |
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</ul> |
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<p> |
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Details on how to specify the system properties or properties in a property file |
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and how to configure the JNDI Context are explained in detail in the |
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<a href="SyncFactory.html"><code>SyncFactory</code></a> class description. |
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<p> |
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<b>2.3 SyncFactory Provider Instance Generation Policies</b> |
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<p> |
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The <code>SyncFactory</code> generates a requested <code>SyncProvider</code> |
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object if the provider has been correctly registered. The |
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following policies are adhered to when either a disconnected <code>RowSet</code> object |
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is instantiated with a specified <code>SyncProvider</code> implementation or is |
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reconfigured at runtime with an alternative <code>SyncProvider</code> object. |
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<ul> |
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<li> If a <code>SyncProvider</code> object is specified and the <code>SyncFactory</code> |
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contains <i>no</i> reference to the provider, a <code>SyncFactoryException</code> is |
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thrown. |
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<li> If a <code>SyncProvider</code> object is specified and the <code>SyncFactory</code> |
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contains a reference to the provider, the requested provider is supplied. |
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<li> If no <code>SyncProvider</code> object is specified, the reference |
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implementation provider <code>RIOptimisticProvider</code> is supplied. |
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</ul> |
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<p> |
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These policies are explored in more detail in the <a href="SyncFactory.html"> |
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<code>SyncFactory</code></a> class. |
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<h3><a name="impl">3.0 SyncProvider Implementer's Guide</a></h3> |
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<b>3.1 Requirements</b> |
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<p> |
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A compliant <code>SyncProvider</code> implementation that is fully pluggable |
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into the <code>SyncFactory</code> <b>must</b> extend and implement all |
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abstract methods in the <a href="SyncProvider.html"><code>SyncProvider</code></a> |
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class. In addition, an implementation <b>must</b> determine the |
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grade, locking and updatable view capabilities defined in the |
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<code>SyncProvider</code> class definition. One or more of the |
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<code>SyncProvider</code> description criteria <b>must</b> be supported. It |
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is expected that vendor implementations will offer a range of grade, locking, and |
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updatable view capabilities. |
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<p> |
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Furthermore, the <code>SyncProvider</code> naming convention <b>must</b> be followed as |
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detailed in the <a href="SyncProvider.html"><code>SyncProvider</code></a> class |
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description. |
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<p> |
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<b>3.2 Grades</b> |
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<p> |
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JSR 114 defines a set of grades to describe the quality of synchronization |
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a <code>SyncProvider</code> object can offer a disconnected <code>RowSet</code> |
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object. These grades are listed from the lowest quality of service to the highest. |
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<ul> |
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<li><b>GRADE_NONE</b> - No synchronization with the originating data source is |
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provided. A <code>SyncProvider</code> implementation returning this grade will simply |
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attempt to write any data that has changed in the <code>RowSet</code> object to the |
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underlying data source, overwriting whatever is there. No attempt is made to compare |
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original values with current values to see if there is a conflict. The |
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<code>RIXMLProvider</code> is implemented with this grade. |
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<li><b>GRADE_CHECK_MODIFIED_AT_COMMIT</b> - A low grade of optimistic synchronization. |
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A <code>SyncProvider</code> implementation returning this grade |
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will check for conflicts in rows that have changed between the last synchronization |
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and the current synchronization under way. Any changes in the originating data source |
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that have been modified will not be reflected in the disconnected <code>RowSet</code> |
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object. If there are no conflicts, changes in the <code>RowSet</code> object will be |
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written to the data source. If there are conflicts, no changes are written. |
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The <code>RIOptimisticProvider</code> implementation uses this grade. |
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<li><b>GRADE_CHECK_ALL_AT_COMMIT</b> - A high grade of optimistic synchronization. |
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A <code>SyncProvider</code> implementation returning this grade |
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will check all rows, including rows that have not changed in the disconnected |
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<code>RowSet</code> object. In this way, any changes to rows in the underlying |
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data source will be reflected in the disconnected <code>RowSet</code> object |
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when the synchronization finishes successfully. |
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<li><b>GRADE_LOCK_WHEN_MODIFIED</b> - A pessimistic grade of synchronization. |
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<code>SyncProvider</code> implementations returning this grade will lock |
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the row in the originating data source that corresponds to the row being changed |
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in the <code>RowSet</code> object to reduce the possibility of other |
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processes modifying the same data in the data source. |
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<li><b>GRADE_LOCK_WHEN_LOADED</b> - A higher pessimistic synchronization grade. |
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A <code>SyncProvider</code> implementation returning this grade will lock |
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the entire view and/or table affected by the original query used to |
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populate a <code>RowSet</code> object. |
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</ul> |
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<p> |
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<b>3.3 Locks</b> |
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<p> |
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JSR 114 defines a set of constants that specify whether any locks have been |
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placed on a <code>RowSet</code> object's underlying data source and, if so, |
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on which constructs the locks are placed. These locks will remain on the data |
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source while the <code>RowSet</code> object is disconnected from the data source. |
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<P> |
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These constants <b>should</b> be considered complementary to the |
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grade constants. The default setting for the majority of grade settings requires |
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that no data source locks remain when a <code>RowSet</code> object is disconnected |
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from its data source. |
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The grades <code>GRADE_LOCK_WHEN_MODIFIED</code> and |
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<code>GRADE_LOCK_WHEN_LOADED</code> allow a disconnected <code>RowSet</code> object |
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to have a fine-grained control over the degree of locking. |
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<ul> |
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<li><b>DATASOURCE_NO_LOCK</b> - No locks remain on the originating data source. |
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This is the default lock setting for all <code>SyncProvider</code> implementations |
|
346 |
unless otherwise directed by a <code>RowSet</code> object. |
|
| 24197 | 347 |
|
| 2 | 348 |
<li><b>DATASOURCE_ROW_LOCK</b> - A lock is placed on the rows that are touched by |
349 |
the original SQL query used to populate the <code>RowSet</code> object. |
|
| 24197 | 350 |
|
| 2 | 351 |
<li><b>DATASOURCE_TABLE_LOCK</b> - A lock is placed on all tables that are touched |
352 |
by the query that was used to populate the <code>RowSet</code> object. |
|
| 24197 | 353 |
|
| 2 | 354 |
<li><b>DATASOURCE_DB_LOCK</b> |
355 |
A lock is placed on the entire data source that is used by the <code>RowSet</code> |
|
356 |
object. |
|
357 |
</ul> |
|
358 |
<p> |
|
359 |
<b>3.4 Updatable Views</b> |
|
360 |
<p> |
|
361 |
A <code>RowSet</code> object may be populated with data from an SQL <code>VIEW</code>. |
|
362 |
The following constants indicate whether a <code>SyncProvider</code> object can |
|
363 |
update data in the table or tables from which the <code>VIEW</code> was derived. |
|
364 |
<ul> |
|
365 |
<li><b>UPDATABLE_VIEW_SYNC</b> |
|
366 |
Indicates that a <code>SyncProvider</code> implementation supports synchronization |
|
367 |
to the table or tables from which the SQL <code>VIEW</code> used to populate a |
|
368 |
a <code>RowSet</code> object is derived. |
|
| 24197 | 369 |
|
| 2 | 370 |
<li><b>NONUPDATABLE_VIEW_SYNC</b> |
371 |
Indicates that a <code>SyncProvider</code> implementation does <b>not</b> support |
|
372 |
synchronization to the table or tables from which the SQL <code>VIEW</code> |
|
373 |
used to populate a <code>RowSet</code> object is derived. |
|
374 |
</ul> |
|
375 |
<p> |
|
376 |
<b>3.5 Usage of <code>SyncProvider</code> Grading and Locking</b> |
|
377 |
<p> |
|
378 |
In the example below, the reference <tt>CachedRowSetImpl</tt> implementation |
|
379 |
reconfigures its current <tt>SyncProvider</tt> object by calling the |
|
380 |
<tt>setSyncProvider</tt> method.<br> |
|
| 24197 | 381 |
|
| 2 | 382 |
<PRE> |
383 |
CachedRowSetImpl crs = new CachedRowSetImpl(); |
|
384 |
crs.setSyncProvider("com.foo.bar.HASyncProvider");
|
|
385 |
</PRE> |
|
386 |
An application can retrieve the <tt>SyncProvider</tt> object currently in use |
|
387 |
by a disconnected <code>RowSet</code> object. It can also retrieve the |
|
388 |
grade of synchronization with which the provider was implemented and the degree of |
|
389 |
locking currently in use. In addition, an application has the flexibility to set |
|
390 |
the degree of locking to be used, which can increase the possibilities for successful |
|
391 |
synchronization. These operation are shown in the following code fragment. |
|
392 |
<PRE> |
|
393 |
SyncProvider sync = crs.getSyncProvider(); |
|
394 |
||
395 |
switch (sync.getProviderGrade()) {
|
|
396 |
case: SyncProvider.GRADE_CHECK_ALL_AT_COMMIT |
|
397 |
//A high grade of optimistic synchronization |
|
398 |
break; |
|
399 |
case: SyncProvider.GRADE_CHECK_MODIFIED_AT_COMMIT |
|
400 |
//A low grade of optimistic synchronization |
|
401 |
break; |
|
402 |
case: SyncProvider.GRADE_LOCK_WHEN_LOADED |
|
403 |
// A pessimistic synchronization grade |
|
404 |
break; |
|
405 |
case: SyncProvider.GRADE_LOCK_WHEN_MODIFIED |
|
406 |
// A pessimistic synchronization grade |
|
407 |
break; |
|
408 |
case: SyncProvider.GRADE_NONE |
|
409 |
// No synchronization with the originating data source provided |
|
410 |
break; |
|
411 |
} |
|
| 24197 | 412 |
|
| 2 | 413 |
switch (sync.getDataSourcLock() {
|
414 |
case: SyncProvider.DATASOURCE_DB_LOCK |
|
415 |
// A lock is placed on the entire datasource that is used by the |
|
416 |
// <code>RowSet</code> object |
|
417 |
break; |
|
418 |
||
419 |
case: SyncProvider.DATASOURCE_NO_LOCK |
|
420 |
// No locks remain on the originating data source. |
|
421 |
break; |
|
422 |
||
423 |
case: SyncProvider.DATASOURCE_ROW_LOCK |
|
424 |
// A lock is placed on the rows that are touched by the original |
|
425 |
// SQL statement used to populate |
|
426 |
// the RowSet object that is using the SyncProvider |
|
427 |
break; |
|
428 |
||
429 |
case: DATASOURCE_TABLE_LOCK |
|
430 |
// A lock is placed on all tables that are touched by the original |
|
431 |
// SQL statement used to populated |
|
432 |
// the RowSet object that is using the SyncProvider |
|
433 |
break; |
|
434 |
||
435 |
</PRE> |
|
436 |
It is also possible using the static utility method in the |
|
437 |
<code>SyncFactory</code> class to determine the list of <code>SyncProvider</code> |
|
438 |
implementations currently registered with the <code>SyncFactory</code>. |
|
| 24197 | 439 |
|
| 2 | 440 |
<pre> |
| 24197 | 441 |
Enumeration e = SyncFactory.getRegisteredProviders(); |
442 |
</pre> |
|
| 2 | 443 |
|
444 |
||
| 24197 | 445 |
<h3><a name="resolving">4.0 Resolving Synchronization Conflicts</a></h3> |
| 2 | 446 |
|
447 |
The interface <code>SyncResolver</code> provides a way for an application to |
|
448 |
decide manually what to do when a conflict occurs. When the <code>CachedRowSet</code> |
|
449 |
method <code>acceptChanges</code> finishes and has detected one or more conflicts, |
|
450 |
it throws a <code>SyncProviderException</code> object. An application can |
|
451 |
catch the exception and |
|
452 |
have it retrieve a <code>SyncResolver</code> object by calling the method |
|
453 |
<code>SyncProviderException.getSyncResolver()</code>. |
|
454 |
<P> |
|
455 |
A <code>SyncResolver</code> object, which is a special kind of |
|
456 |
<code>CachedRowSet</code> object or |
|
457 |
a <code>JdbcRowSet</code> object that has implemented the <code>SyncResolver</code> |
|
458 |
interface, examines the conflicts row by row. It is a duplicate of the |
|
459 |
<code>RowSet</code> object being synchronized except that it contains only the data |
|
460 |
from the data source this is causing a conflict. All of the other column values are |
|
461 |
set to <code>null</code>. To navigate from one conflict value to another, a |
|
462 |
<code>SyncResolver</code> object provides the methods <code>nextConflict</code> and |
|
463 |
<code>previousConflict</code>. |
|
464 |
<P> |
|
465 |
The <code>SyncResolver</code> interface also |
|
466 |
provides methods for doing the following: |
|
467 |
<UL> |
|
468 |
<LI>finding out whether the conflict involved an update, a delete, or an insert |
|
469 |
<LI>getting the value in the data source that caused the conflict |
|
470 |
<LI>setting the value that should be in the data source if it needs to be changed |
|
471 |
or setting the value that should be in the <code>RowSet</code> object if it needs |
|
472 |
to be changed |
|
473 |
</UL> |
|
474 |
<P> |
|
475 |
When the <code>CachedRowSet</code> method <code>acceptChanges</code> is called, it |
|
476 |
delegates to the <code>RowSet</code> object's <code>SyncProvider</code> object. |
|
477 |
How the writer provided by that <code>SyncProvider</code> object is implemented |
|
478 |
determines what level (grade) of checking for conflicts will be done. After all |
|
479 |
checking for conflicts is completed and one or more conflicts has been found, the method |
|
480 |
<code>acceptChanges</code> throws a <code>SyncProviderException</code> object. The |
|
481 |
application can catch the exception and use it to obtain a <code>SyncResolver</code> object. |
|
482 |
<P> |
|
483 |
The application can then use <code>SyncResolver</code> methods to get information |
|
484 |
about each conflict and decide what to do. If the application logic or the user |
|
485 |
decides that a value in the <code>RowSet</code> object should be the one to |
|
486 |
persist, the application or user can overwrite the data source value with it. |
|
487 |
<P> |
|
488 |
The comment for the <code>SyncResolver</code> interface has more detail. |
|
489 |
||
| 24197 | 490 |
<h3><a name="relspec">5.0 Related Specifications</a></h3> |
| 2 | 491 |
<ul> |
| 24197 | 492 |
<li><a href="http://docs.oracle.com/javase/jndi/tutorial/index.html">JNDI</a> |
| 2 | 493 |
<li><a href="{@docRoot}/../technotes/guides/logging/index.html">Java Logging
|
494 |
APIs</a> |
|
495 |
</ul> |
|
| 24197 | 496 |
<h3><a name="reldocs">6.0 Related Documentation</a></h3> |
| 2 | 497 |
<ul> |
498 |
<li><a href="{@docRoot}/../technotes/tools/index.html#basic">System
|
|
499 |
properties</a> |
|
500 |
<li>Resource Files |
|
| 24197 | 501 |
<li><a href="http://docs.oracle.com/javase/tutorial/jdbc/">DataSource for JDBC |
| 2 | 502 |
Connections</a> |
503 |
</ul> |
|
504 |
||
505 |
</body> |
|
506 |
</html> |