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/* |
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* Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved. |
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* Copyright (c) 2003, 2020, 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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@@ -25,84 +25,84 @@ |
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/** |
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* |
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* Repository for the <code>RowSet</code> reference implementations of the |
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* <code>SyncProvider</code> abstract class. These implementations provide a |
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* disconnected <code>RowSet</code> |
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* Repository for the {@code RowSet} reference implementations of the |
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* {@code SyncProvider} abstract class. These implementations provide a |
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* disconnected {@code RowSet} |
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* object with the ability to synchronize the data in the underlying data |
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* source with its data. These implementations are provided as |
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* the default <code>SyncProvider</code> implementations and are accessible via the |
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* <code>SyncProvider</code> SPI managed by the <code>SyncFactory</code>. |
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* the default {@code SyncProvider} implementations and are accessible via the |
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* {@code SyncProvider} SPI managed by the {@code SyncFactory}. |
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* |
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* <h2>1.0 <code>SyncProvider</code> Reference Implementations</h2> |
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* The main job of a <code>SyncProvider</code> implementation is to manage |
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* <h2>1.0 {@code SyncProvider} Reference Implementations</h2> |
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* The main job of a {@code SyncProvider} implementation is to manage |
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* the reader and writer mechanisms. |
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* The <code>SyncProvider</code> SPI, as specified in the <code>javax.sql.rowset.spi</code> |
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* package, provides a pluggable mechanism by which <code>javax.sql.RowSetReader</code> |
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* and <code>javax.sql.RowSetWriter</code> implementations can be supplied to a disconnected |
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* <code>RowSet</code> object. |
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* The {@code SyncProvider} SPI, as specified in the {@code javax.sql.rowset.spi} |
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* package, provides a pluggable mechanism by which {@code javax.sql.RowSetReader} |
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* and {@code javax.sql.RowSetWriter} implementations can be supplied to a disconnected |
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* {@code RowSet} object. |
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* <P> |
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* A reader, a <code>javax.sql.RowSetReader</code> |
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* object, does the work necessary to populate a <code>RowSet</code> object with data. |
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* A writer, a <code>javax.sql.RowSetWriter</code> object, does the work necessary for |
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* synchronizing a <code>RowSet</code> object's data with the data in the originating |
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* source of data. Put another way, a writer writes a <code>RowSet</code> |
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* A reader, a {@code javax.sql.RowSetReader} |
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* object, does the work necessary to populate a {@code RowSet} object with data. |
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* A writer, a {@code javax.sql.RowSetWriter} object, does the work necessary for |
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* synchronizing a {@code RowSet} object's data with the data in the originating |
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* source of data. Put another way, a writer writes a {@code RowSet} |
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* object's data back to the data source. |
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* <P> |
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* Generally speaking, the course of events is this. The reader makes a connection to |
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* the data source and reads the data from a <code>ResultSet</code> object into its |
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* <code>RowSet</code> object. Then it closes the connection. While |
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* the <code>RowSet</code> object is disconnected, an application makes some modifications |
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* to the data and calls the method <code>acceptChanges</code>. At this point, the |
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* the data source and reads the data from a {@code ResultSet} object into its |
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* {@code RowSet} object. Then it closes the connection. While |
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* the {@code RowSet} object is disconnected, an application makes some modifications |
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* to the data and calls the method {@code acceptChanges}. At this point, the |
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* writer is called to write the changes back to the database table or view |
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* from which the original data came. This is called <i>synchronization</i>. |
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* <P> |
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* If the data in the originating data source has not changed, there is no problem |
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* with just writing the <code>RowSet</code> object's new data to the data source. |
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* with just writing the {@code RowSet} object's new data to the data source. |
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* If it has changed, however, there is a conflict that needs to be resolved. One |
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* way to solve the problem is not to let the data in the data source be changed in |
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* the first place, which can be done by setting locks on a row, a table, or the |
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* whole data source. Setting locks is a way to avoid conflicts, but it can be |
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* very expensive. Another approach, which is at the other end of the spectrum, |
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* is simply to assume that no conflicts will occur and thus do nothing to avoid |
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* conflicts. |
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* Different <code>SyncProvider</code> implementations may handle synchronization in |
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* Different {@code SyncProvider} implementations may handle synchronization in |
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* any of these ways, varying from doing no checking for |
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* conflicts, to doing various levels of checking, to guaranteeing that there are no |
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* conflicts. |
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* <P> |
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* The <code>SyncProvider</code> class offers methods to help a <code>RowSet</code> |
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* The {@code SyncProvider} class offers methods to help a {@code RowSet} |
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* object discover and manage how a provider handles synchronization. |
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* The method <code>getProviderGrade</code> returns the |
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* The method {@code getProviderGrade} returns the |
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* grade of synchronization a provider offers. An application can |
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* direct the provider to use a particular level of locking by calling |
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* the method <code>setDataSourceLock</code> and specifying the level of locking desired. |
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* If a <code>RowSet</code> object's data came from an SQL <code>VIEW</code>, an |
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* application may call the method <code>supportsUpdatableView</code> to |
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* find out whether the <code>VIEW</code> can be updated. |
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* the method {@code setDataSourceLock} and specifying the level of locking desired. |
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* If a {@code RowSet} object's data came from an SQL {@code VIEW}, an |
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* application may call the method {@code supportsUpdatableView} to |
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* find out whether the {@code VIEW} can be updated. |
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* <P> |
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* Synchronization is done completely behind the scenes, so it is third party vendors of |
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* synchronization provider implementations who have to take care of this complex task. |
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* Application programmers can decide which provider to use and the level of locking to |
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* be done, but they are free from having to worry about the implementation details. |
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* <P> |
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* The JDBC <code>RowSet</code> Implementations reference implementation provides two |
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* implementations of the <code>SyncProvider</code> class: |
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* The JDBC {@code RowSet} Implementations reference implementation provides two |
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* implementations of the {@code SyncProvider} class: |
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* |
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* <UL> |
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* <LI> |
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* <b><code>RIOptimisticProvider</code></b> - provides the <code>javax.sql.RowSetReader</code> |
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* and <code>javax.sql.RowSetWriter</code> interface implementations and provides |
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* <b>{@code RIOptimisticProvider}</b> - provides the {@code javax.sql.RowSetReader} |
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* and {@code javax.sql.RowSetWriter} interface implementations and provides |
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* an optimistic concurrency model for synchronization. This model assumes that there |
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* will be few conflicts and therefore uses a relatively low grade of synchronization. |
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* If no other provider is available, this is the default provider that the |
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* <code>SyncFactory</code> will supply to a <code>RowSet</code> object. |
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* {@code SyncFactory} will supply to a {@code RowSet} object. |
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* <br> |
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* <LI> |
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* <b><code>RIXMLProvider</code></b> - provides the <code>XmlReader</code> (an extension |
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* of the <code>javax.sql.RowSetReader</code> interface) and the <code>XmlWriter</code> |
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* (an extension of the <code>javax.sql.RowSetWriter</code> interface) to enable |
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* <code>WebRowSet</code> objects to write their state to a |
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* well formed XML document according to the <code>WebRowSet</code> XML schema |
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* <b>{@code RIXMLProvider}</b> - provides the {@code XmlReader} (an extension |
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* of the {@code javax.sql.RowSetReader} interface) and the {@code XmlWriter} |
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* (an extension of the {@code javax.sql.RowSetWriter} interface) to enable |
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* {@code WebRowSet} objects to write their state to a |
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* well formed XML document according to the {@code WebRowSet} XML schema |
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* definition.<br> |
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* </UL> |
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* |
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@@ -117,12 +117,12 @@ |
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* properties. The general rule is that a RowSet is required to set only the |
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* properties that it uses.<br> |
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* <br> |
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* The <code>command</code> property contains the query that determines what |
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* data a <code>RowSet</code> will contain. Rowsets have methods for setting a query's |
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* The {@code command} property contains the query that determines what |
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* data a {@code RowSet} will contain. Rowsets have methods for setting a query's |
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* parameter(s), which means that a query can be executed multiple times with |
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* different parameters to produce different result sets. Or the query can be |
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* changed to something completely new to get a new result set. |
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* <p>Once a rowset contains the rows from a <code>ResultSet</code> object or some |
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* <p>Once a rowset contains the rows from a {@code ResultSet} object or some |
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* other data source, its column values can be updated, and its rows can be |
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* inserted or deleted. Any method that causes a change in the rowset's values |
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* or cursor position also notifies any object that has been registered as |
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@@ -134,23 +134,23 @@ |
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* source to keep the rowset and its data source synchronized. Although this |
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* involves many operations behind the scenes, it is completely transparent |
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* to the application programmer and remains the concern of the RowSet provider |
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* developer. All an application has to do is invoke the method <code>acceptChanges</code>, |
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* developer. All an application has to do is invoke the method {@code acceptChanges}, |
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* and the data source backing the rowset will be updated to match the current |
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* values in the rowset. </p> |
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* |
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* <p>A disconnected rowset, such as a <code>CachedRowSet</code> or <code>WebRowSet</code> |
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* <p>A disconnected rowset, such as a {@code CachedRowSet} or {@code WebRowSet} |
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* object, establishes a connection to populate itself with data from a database |
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* and then closes the connection. The <code>RowSet</code> object will remain |
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* and then closes the connection. The {@code RowSet} object will remain |
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* disconnected until it wants to propagate changes back to its database table, |
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* which is optional. To write its changes back to the database (synchronize with |
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* the database), the rowset establishes a connection, write the changes, and then |
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* once again disconnects itself.<br> |
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* </p> |
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* |
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* <h2> 3.0 Other Possible Implementations</h2> |
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* There are many other possible implementations of the <code>SyncProvider</code> abstract |
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* There are many other possible implementations of the {@code SyncProvider} abstract |
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* class. One possibility is to employ a more robust synchronization model, which |
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* would give a <code>RowSet</code> object increased trust in the provider's |
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* would give a {@code RowSet} object increased trust in the provider's |
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* ability to get any updates back to the original data source. Another possibility |
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* is a more formal synchronization mechanism such as SyncML |
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* (<a href="http://www.syncml.org/">http://www.syncml.org/</a>) <br> |
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