/* |
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* Copyright (c) 2003, 2013, 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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* |
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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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* |
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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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* |
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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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* |
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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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package javax.sql.rowset.spi; |
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import javax.sql.*; |
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/** |
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* The synchronization mechanism that provides reader/writer capabilities for |
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* disconnected <code>RowSet</code> objects. |
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* A <code>SyncProvider</code> implementation is a class that extends the |
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* <code>SyncProvider</code> abstract class. |
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* <P> |
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* A <code>SyncProvider</code> implementation is |
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* identified by a unique ID, which is its fully qualified class name. |
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* This name must be registered with the |
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* <code>SyncFactory</code> SPI, thus making the implementation available to |
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* all <code>RowSet</code> implementations. |
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* The factory mechanism in the reference implementation uses this name to instantiate |
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* the implementation, which can then provide a <code>RowSet</code> object with its |
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* reader (a <code>javax.sql.RowSetReader</code> object) and its writer (a |
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* <code>javax.sql.RowSetWriter</code> object). |
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* <P> |
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* The Jdbc <code>RowSet</code> Implementations specification provides two |
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* reference implementations of the <code>SyncProvider</code> abstract class: |
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* <code>RIOptimisticProvider</code> and <code>RIXMLProvider</code>. |
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* The <code>RIOptimisticProvider</code> can set any <code>RowSet</code> |
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* implementation with a <code>RowSetReader</code> object and a |
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* <code>RowSetWriter</code> object. However, only the <code>RIXMLProvider</code> |
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* implementation can set an <code>XmlReader</code> object and an |
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* <code>XmlWriter</code> object. A <code>WebRowSet</code> object uses the |
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* <code>XmlReader</code> object to read data in XML format to populate itself with that |
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* data. It uses the <code>XmlWriter</code> object to write itself to a stream or |
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* <code>java.io.Writer</code> object in XML format. |
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* |
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* <h3>1.0 Naming Convention for Implementations</h3> |
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* As a guide to naming <code>SyncProvider</code> |
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* implementations, the following should be noted: |
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* <UL> |
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* <li>The name for a <code>SyncProvider</code> implementation |
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* is its fully qualified class name. |
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* <li>It is recommended that vendors supply a |
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* <code>SyncProvider</code> implementation in a package named <code>providers</code>. |
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* </UL> |
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* <p> |
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* For instance, if a vendor named Fred, Inc. offered a |
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* <code>SyncProvider</code> implementation, you could have the following: |
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* <PRE> |
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* Vendor name: Fred, Inc. |
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* Domain name of vendor: com.fred |
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* Package name: com.fred.providers |
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* SyncProvider implementation class name: HighAvailabilityProvider |
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* |
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* Fully qualified class name of SyncProvider implementation: |
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* com.fred.providers.HighAvailabilityProvider |
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* </PRE> |
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* <P> |
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* The following line of code uses the fully qualified name to register |
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* this implementation with the <code>SyncFactory</code> static instance. |
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* <PRE> |
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* SyncFactory.registerProvider( |
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* "com.fred.providers.HighAvailabilityProvider"); |
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* </PRE> |
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* <P> |
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* The default <code>SyncProvider</code> object provided with the reference |
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* implementation uses the following name: |
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* <pre> |
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* com.sun.rowset.providers.RIOptimisticProvider |
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* </pre> |
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* <p> |
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* A vendor can register a <code>SyncProvider</code> implementation class name |
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* with Oracle Corporation by sending email to jdbc@sun.com. |
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* Oracle will maintain a database listing the |
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* available <code>SyncProvider</code> implementations for use with compliant |
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* <code>RowSet</code> implementations. This database will be similar to the |
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* one already maintained to list available JDBC drivers. |
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* <P> |
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* Vendors should refer to the reference implementation synchronization |
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* providers for additional guidance on how to implement a new |
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* <code>SyncProvider</code> implementation. |
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* |
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* <h3>2.0 How a <code>RowSet</code> Object Gets Its Provider</h3> |
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* |
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* A disconnected <code>Rowset</code> object may get access to a |
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* <code>SyncProvider</code> object in one of the following two ways: |
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* <UL> |
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* <LI>Using a constructor<BR> |
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* <PRE> |
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* CachedRowSet crs = new CachedRowSet( |
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* "com.fred.providers.HighAvailabilitySyncProvider"); |
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* </PRE> |
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* <LI>Using the <code>setSyncProvider</code> method |
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* <PRE> |
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* CachedRowSet crs = new CachedRowSet(); |
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* crs.setSyncProvider("com.fred.providers.HighAvailabilitySyncProvider"); |
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* </PRE> |
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* </UL> |
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* <p> |
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* By default, the reference implementations of the <code>RowSet</code> synchronization |
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* providers are always available to the Java platform. |
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* If no other pluggable synchronization providers have been correctly |
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* registered, the <code>SyncFactory</code> will automatically generate |
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* an instance of the default <code>SyncProvider</code> reference implementation. |
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* Thus, in the preceding code fragment, if no implementation named |
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* <code>com.fred.providers.HighAvailabilitySyncProvider</code> has been |
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* registered with the <code>SyncFactory</code> instance, <i>crs</i> will be |
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* assigned the default provider in the reference implementation, which is |
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* <code>com.sun.rowset.providers.RIOptimisticProvider</code>. |
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* |
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* <h3>3.0 Violations and Synchronization Issues</h3> |
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* If an update between a disconnected <code>RowSet</code> object |
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* and a data source violates |
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* the original query or the underlying data source constraints, this will |
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* result in undefined behavior for all disconnected <code>RowSet</code> implementations |
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* and their designated <code>SyncProvider</code> implementations. |
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* Not defining the behavior when such violations occur offers greater flexibility |
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* for a <code>SyncProvider</code> |
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* implementation to determine its own best course of action. |
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* <p> |
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* A <code>SyncProvider</code> implementation |
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* may choose to implement a specific handler to |
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* handle a subset of query violations. |
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* However if an original query violation or a more general data source constraint |
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* violation is not handled by the <code>SyncProvider</code> implementation, |
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* all <code>SyncProvider</code> |
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* objects must throw a <code>SyncProviderException</code>. |
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* |
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* <h3>4.0 Updatable SQL VIEWs</h3> |
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* It is possible for any disconnected or connected <code>RowSet</code> object to be populated |
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* from an SQL query that is formulated originally from an SQL <code>VIEW</code>. |
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* While in many cases it is possible for an update to be performed to an |
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* underlying view, such an update requires additional metadata, which may vary. |
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* The <code>SyncProvider</code> class provides two constants to indicate whether |
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* an implementation supports updating an SQL <code>VIEW</code>. |
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* <ul> |
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* <li><code><b>NONUPDATABLE_VIEW_SYNC</b></code> - Indicates that a <code>SyncProvider</code> |
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* implementation does not support synchronization with an SQL <code>VIEW</code> as the |
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* underlying source of data for the <code>RowSet</code> object. |
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* <li><code><b>UPDATABLE_VIEW_SYNC</b></code> - Indicates that a |
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* <code>SyncProvider</code> implementation |
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* supports synchronization with an SQL <code>VIEW</code> as the underlying source |
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* of data. |
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* </ul> |
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* <P> |
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* The default is for a <code>RowSet</code> object not to be updatable if it was |
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* populated with data from an SQL <code>VIEW</code>. |
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* |
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* <h3>5.0 <code>SyncProvider</code> Constants</h3> |
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* The <code>SyncProvider</code> class provides three sets of constants that |
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* are used as return values or parameters for <code>SyncProvider</code> methods. |
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* <code>SyncProvider</code> objects may be implemented to perform synchronization |
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* between a <code>RowSet</code> object and its underlying data source with varying |
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* degrees of of care. The first group of constants indicate how synchronization |
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* is handled. For example, <code>GRADE_NONE</code> indicates that a |
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* <code>SyncProvider</code> object will not take any care to see what data is |
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* valid and will simply write the <code>RowSet</code> data to the data source. |
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* <code>GRADE_MODIFIED_AT_COMMIT</code> indicates that the provider will check |
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* only modified data for validity. Other grades check all data for validity |
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* or set locks when data is modified or loaded. |
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* <OL> |
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* <LI>Constants to indicate the synchronization grade of a |
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* <code>SyncProvider</code> object |
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* <UL> |
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* <LI>SyncProvider.GRADE_NONE |
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* <LI>SyncProvider.GRADE_MODIFIED_AT_COMMIT |
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* <LI>SyncProvider.GRADE_CHECK_ALL_AT_COMMIT |
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* <LI>SyncProvider.GRADE_LOCK_WHEN_MODIFIED |
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* <LI>SyncProvider.GRADE_LOCK_WHEN_LOADED |
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* </UL> |
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* <LI>Constants to indicate what locks are set on the data source |
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* <UL> |
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* <LI>SyncProvider.DATASOURCE_NO_LOCK |
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* <LI>SyncProvider.DATASOURCE_ROW_LOCK |
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* <LI>SyncProvider.DATASOURCE_TABLE_LOCK |
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* <LI>SyncProvider.DATASOURCE_DB_LOCK |
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* </UL> |
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* <LI>Constants to indicate whether a <code>SyncProvider</code> object can |
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* perform updates to an SQL <code>VIEW</code> <BR> |
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* These constants are explained in the preceding section (4.0). |
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* <UL> |
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* <LI>SyncProvider.UPDATABLE_VIEW_SYNC |
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* <LI>SyncProvider.NONUPDATABLE_VIEW_SYNC |
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* </UL> |
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* </OL> |
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* |
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* @author Jonathan Bruce |
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* @see javax.sql.rowset.spi.SyncFactory |
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* @see javax.sql.rowset.spi.SyncFactoryException |
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*/ |
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public abstract class SyncProvider { |
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/** |
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* Creates a default <code>SyncProvider</code> object. |
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*/ |
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public SyncProvider() { |
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} |
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/** |
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* Returns the unique identifier for this <code>SyncProvider</code> object. |
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* |
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* @return a <code>String</code> object with the fully qualified class name of |
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* this <code>SyncProvider</code> object |
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*/ |
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public abstract String getProviderID(); |
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/** |
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* Returns a <code>javax.sql.RowSetReader</code> object, which can be used to |
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* populate a <code>RowSet</code> object with data. |
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* |
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* @return a <code>javax.sql.RowSetReader</code> object |
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*/ |
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public abstract RowSetReader getRowSetReader(); |
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/** |
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* Returns a <code>javax.sql.RowSetWriter</code> object, which can be |
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* used to write a <code>RowSet</code> object's data back to the |
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* underlying data source. |
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* |
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* @return a <code>javax.sql.RowSetWriter</code> object |
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*/ |
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public abstract RowSetWriter getRowSetWriter(); |
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/** |
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* Returns a constant indicating the |
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* grade of synchronization a <code>RowSet</code> object can expect from |
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* this <code>SyncProvider</code> object. |
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* |
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* @return an int that is one of the following constants: |
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* SyncProvider.GRADE_NONE, |
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* SyncProvider.GRADE_CHECK_MODIFIED_AT_COMMIT, |
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* SyncProvider.GRADE_CHECK_ALL_AT_COMMIT, |
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* SyncProvider.GRADE_LOCK_WHEN_MODIFIED, |
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* SyncProvider.GRADE_LOCK_WHEN_LOADED |
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*/ |
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public abstract int getProviderGrade(); |
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/** |
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* Sets a lock on the underlying data source at the level indicated by |
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* <i>datasource_lock</i>. This should cause the |
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* <code>SyncProvider</code> to adjust its behavior by increasing or |
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* decreasing the level of optimism it provides for a successful |
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* synchronization. |
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* |
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* @param datasource_lock one of the following constants indicating the severity |
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* level of data source lock required: |
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* <pre> |
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* SyncProvider.DATASOURCE_NO_LOCK, |
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* SyncProvider.DATASOURCE_ROW_LOCK, |
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* SyncProvider.DATASOURCE_TABLE_LOCK, |
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* SyncProvider.DATASOURCE_DB_LOCK, |
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* </pre> |
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* @throws SyncProviderException if an unsupported data source locking level |
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* is set. |
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* @see #getDataSourceLock |
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*/ |
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public abstract void setDataSourceLock(int datasource_lock) |
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throws SyncProviderException; |
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/** |
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* Returns the current data source lock severity level active in this |
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* <code>SyncProvider</code> implementation. |
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* |
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* @return a constant indicating the current level of data source lock |
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* active in this <code>SyncProvider</code> object; |
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* one of the following: |
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* <pre> |
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* SyncProvider.DATASOURCE_NO_LOCK, |
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* SyncProvider.DATASOURCE_ROW_LOCK, |
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* SyncProvider.DATASOURCE_TABLE_LOCK, |
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* SyncProvider.DATASOURCE_DB_LOCK |
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* </pre> |
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* @throws SyncProviderException if an error occurs determining the data |
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* source locking level. |
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* @see #setDataSourceLock |
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*/ |
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public abstract int getDataSourceLock() |
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throws SyncProviderException; |
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/** |
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* Returns whether this <code>SyncProvider</code> implementation |
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* can perform synchronization between a <code>RowSet</code> object |
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* and the SQL <code>VIEW</code> in the data source from which |
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* the <code>RowSet</code> object got its data. |
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* |
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* @return an <code>int</code> saying whether this <code>SyncProvider</code> |
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* object supports updating an SQL <code>VIEW</code>; one of the |
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* following: |
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* SyncProvider.UPDATABLE_VIEW_SYNC, |
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* SyncProvider.NONUPDATABLE_VIEW_SYNC |
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*/ |
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public abstract int supportsUpdatableView(); |
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/** |
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* Returns the release version of this <code>SyncProvider</code> instance. |
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* |
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* @return a <code>String</code> detailing the release version of the |
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* <code>SyncProvider</code> implementation |
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*/ |
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public abstract String getVersion(); |
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/** |
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* Returns the vendor name of this <code>SyncProvider</code> instance |
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* |
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* @return a <code>String</code> detailing the vendor name of this |
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* <code>SyncProvider</code> implementation |
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*/ |
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public abstract String getVendor(); |
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/* |
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* Standard description of synchronization grades that a SyncProvider |
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* could provide. |
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*/ |
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/** |
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* Indicates that no synchronization with the originating data source is |
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* provided. A <code>SyncProvider</code> |
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* implementation returning this grade will simply attempt to write |
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* updates in the <code>RowSet</code> object to the underlying data |
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* source without checking the validity of any data. |
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* |
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*/ |
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public static final int GRADE_NONE = 1; |
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/** |
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* Indicates a low level optimistic synchronization grade with |
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* respect to the originating data source. |
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* |
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* A <code>SyncProvider</code> implementation |
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* returning this grade will check only rows that have changed. |
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* |
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*/ |
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public static final int GRADE_CHECK_MODIFIED_AT_COMMIT = 2; |
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/** |
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* Indicates a high level optimistic synchronization grade with |
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* respect to the originating data source. |
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* |
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* A <code>SyncProvider</code> implementation |
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* returning this grade will check all rows, including rows that have not |
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* changed. |
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*/ |
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public static final int GRADE_CHECK_ALL_AT_COMMIT = 3; |
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/** |
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* Indicates a pessimistic synchronization grade with |
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* respect to the originating data source. |
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* |
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* A <code>SyncProvider</code> |
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* implementation returning this grade will lock the row in the originating |
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* data source. |
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*/ |
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public static final int GRADE_LOCK_WHEN_MODIFIED = 4; |
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/** |
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* Indicates the most pessimistic synchronization grade with |
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* respect to the originating |
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* data source. A <code>SyncProvider</code> |
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* implementation returning this grade will lock the entire view and/or |
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* table affected by the original statement used to populate a |
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* <code>RowSet</code> object. |
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*/ |
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public static final int GRADE_LOCK_WHEN_LOADED = 5; |
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/** |
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* Indicates that no locks remain on the originating data source. This is the default |
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* lock setting for all <code>SyncProvider</code> implementations unless |
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* otherwise directed by a <code>RowSet</code> object. |
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*/ |
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public static final int DATASOURCE_NO_LOCK = 1; |
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/** |
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* Indicates that a lock is placed on the rows that are touched by the original |
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* SQL statement used to populate the <code>RowSet</code> object |
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* that is using this <code>SyncProvider</code> object. |
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*/ |
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public static final int DATASOURCE_ROW_LOCK = 2; |
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/** |
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* Indicates that a lock is placed on all tables that are touched by the original |
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* SQL statement used to populate the <code>RowSet</code> object |
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* that is using this <code>SyncProvider</code> object. |
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*/ |
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public static final int DATASOURCE_TABLE_LOCK = 3; |
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/** |
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* Indicates that a lock is placed on the entire data source that is the source of |
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* data for the <code>RowSet</code> object |
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* that is using this <code>SyncProvider</code> object. |
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*/ |
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public static final int DATASOURCE_DB_LOCK = 4; |
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/** |
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* Indicates that a <code>SyncProvider</code> implementation |
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* supports synchronization between a <code>RowSet</code> object and |
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* the SQL <code>VIEW</code> used to populate it. |
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*/ |
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public static final int UPDATABLE_VIEW_SYNC = 5; |
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/** |
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* Indicates that a <code>SyncProvider</code> implementation |
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* does <B>not</B> support synchronization between a <code>RowSet</code> |
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* object and the SQL <code>VIEW</code> used to populate it. |
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*/ |
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public static final int NONUPDATABLE_VIEW_SYNC = 6; |
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} |