jdk/src/share/classes/javax/sql/rowset/package.html

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  <title>javax.sql.rowset Package</title>
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<!-- Description clause -->
Standard interfaces and base classes for JDBC <code>RowSet</code>
implementations. This package contains interfaces and classes 
that a standard <code>RowSet</code> implementation either implements or extends.


<h2>Table of Contents</h2>
<ul>
<li><a href="#pkgspec">1.0 Package Specification</a>
<li><a href="#stdrowset">2.0 Standard RowSet Definitions</a>
<li><a href="#impl">3.0 Implementer's Guide</a>
<li><a href="#relspec">4.0 Related Specifications</a>
<li><a href="#reldocs">5.0 Related Documentation</a>
</ul>

<h3><a name="pkgspec">1.0 Package Specification</a></h3>
This package specifies five standard JDBC <code>RowSet</code> interfaces.
 All five extend the 
<a href="../RowSet.html">RowSet</a> interface described in the JDBC 3.0
specification.  It is anticipated that additional definitions
of more specialized JDBC <code>RowSet</code> types will emerge as this technology 
matures. Future definitions <i>should</i> be specified as subinterfaces using 
inheritance similar to the way it is used in this specification.
<p>
<i>Note:</i> The interface definitions provided in this package form the basis for
all compliant JDBC <code>RowSet</code> implementations. Vendors and more advanced
developers who intend to provide their own compliant <code>RowSet</code> implementations 
should pay particular attention to the assertions detailed in specification
interfaces. 

<h3><a name="stdrowset">2.0 Standard RowSet Definitions</a></h3>
<ul>
<li><a href="JdbcRowSet.html"><b><code>JdbcRowSet</code></b></a> - A wrapper around 
a <tt>ResultSet</tt> object that makes it possible to use the result set as a 
JavaBeans&trade; component. Thus,
a <tt>JdbcRowSet</tt> object can be a Bean that any tool
makes available for assembling an application as part of a component based
architecture . A <tt>JdbcRowSet</tt> object is a connected <code>RowSet</code>
object, that is, it 
<b>must</b> continually maintain its connection to its data source using a JDBC
technology-enabled driver ("JDBC driver"). In addition, a <code>JdbcRowSet</code>
object provides a fully updatable and scrollable tabular 
data structure as defined in the JDBC 3.0 specification.
<p>
<li><a href="CachedRowSet.html">
<b><code>CachedRowSet</code>&trade;</b></a>
 - A <tt>CachedRowSet</tt> object is a JavaBeans&trade;
 component that is scrollable, updatable, serializable, and generally disconnected from
 the source of its data. A <tt>CachedRowSet</tt> object
typically contains rows from a result set, but it can also contain rows from any
file with a tabular format, such as a spreadsheet. <tt>CachedRowSet</tt> implementations 
<b>must</b> use the <tt>SyncFactory</tt> to manage and obtain pluggable
<code>SyncProvider</code> objects to provide synchronization between the
disconnected <code>RowSet</code> object and the originating data source. 
Typically a <code>SyncProvider</code> implementation relies upon a JDBC
driver to obtain connectivity to a particular data source.
Further details on this mechanism are discussed in the <a
href="spi/package-summary.html"><code>javax.sql.rowset.spi</code></a> package
specification.
<p>
<li><a href="WebRowSet.html"><b><code>WebRowSet</code></b></a> - A 
<code>WebRowSet</code> object is an extension of <tt>CachedRowSet</tt>
that can read and write a <code>RowSet</code> object in a well formed XML format.
This class calls an <a href="spi/XmlReader.html"><code>XmlReader</code></a> object 
(an extension of the <a href="../RowSetReader.html"><code>RowSetReader</code></a>
interface) to read a rowset in XML format. It calls an 
<a href="spi/XmlWriter.html"><code>XmlWriter</code></a> object (an extension of the 
<a href="../RowSetWriter.html"><code>RowSetWriter</code></a> interface) 
to write a rowset in XML format. The reader and writer required by
<code>WebRowSet</code> objects are provided by the
<code>SyncFactory</code> in the form of <code>SyncProvider</code>
implementations. In order to ensure well formed XML usage, a standard generic XML
Schema is defined and published at
<a href="http://java.sun.com/xml/ns/jdbc/webrowset.xsd">
<code>http://java.sun.com/xml/ns/jdbc/webrowset.xsd</code></a>.
<p>   
<li><a href="FilteredRowSet.html"><b><code>FilteredRowSet</code></b></a> - A
<tt>FilteredRowSet</tt> object provides filtering functionality in a programmatic
and extensible way. There are many instances when a <tt>RowSet</tt> <code>object</code>
has a need to provide filtering in its contents without sacrificing the disconnected
environment, thus saving the expense of having to create a connection to the data source.
Solutions to this need vary from providing heavyweight full scale 
SQL query abilities, to portable components, to more lightweight 
approaches. A <code>FilteredRowSet</code> object consumes
an implementation of the <a href="Predicate.html"><code>Predicate</code></a> 
interface, which <b>may</b> define a filter at run time. In turn, a
<code>FilteredRowSet</code> object is tasked with enforcing the set filter for both
inbound and outbound read and write operations. That is, all filters can be
considered as bi-directional. No standard filters are defined;
however, sufficient mechanics are specified to permit any required filter to be
implemented.
<p>
<li><a href="JoinRowSet.html"><b><code>JoinRowSet</code></b></a> - The <tt>JoinRowSet</tt>
interface  describes a mechanism by which relationships can be established between 
two or more standard <code>RowSet</code> implementations. Any number of <tt>RowSet</tt>
 objects can be added to a <tt>JoinRowSet</tt> object provided  the <tt>RowSet</tt>objects 
can be related  in a SQL <tt>JOIN</tt> like fashion. By definition, the SQL <tt>JOIN</tt> 
statement  is used to combine the data contained in two (<i>or more</i>) relational
database tables based upon a common attribute. By establishing and then enforcing
column matches, a <tt>JoinRowSet</tt> object establishes relationships between
<tt>RowSet</tt> instances without the need to touch the originating data source.     
</ul>

<h3><a name="impl">3.0 Implementer's Guide</a></h3>
Compliant implementations of JDBC <code>RowSet</code> Implementations 
<b>must</b> follow the assertions described in this specification. In accordance
with the terms of the <a href="http://www.jcp.org">Java Community Process</a>, a
Test Compatibility Kit (TCK) can be licensed to ensure compatibility with the
specification. The following paragraphs outline a number of starting points for
implementers of the standard JDBC <code>RowSet</code> definitions. Implementers
should also consult the <i>Implementer's Guide</i> in the <a
href="spi/package-summary.html">javax.sql.rowset.spi</a> package for guidelines
on <a href="spi/SyncProvider.html"><code>SyncProvider</code></a> implementations.
<p>
<ul>
<li><b>3.1 Constructor</b>
<p>
    All <code>RowSet</code> implementations <strong>must</strong> provide a
no-argument constructor.
</li>
<li><b>3.2 Role of the <code>BaseRowSet</code> Class</b>
<p>
A compliant JDBC <code>RowSet</code> implementation <b>must</b> implement one or more 
standard interfaces specified in this package and and <b>may</b> extend the 
<a href="BaseRowSet.html"><code>BaseRowSet</code></a> abstract class. For example, a 
<code>CachedRowSet</code> implementation must implement the <code>CachedRowSet</code>
interface and extend the <code>BaseRowSet</code> abstract class. The
<code>BaseRowSet</code> class provides the standard architecture on which all
<code>RowSet</code> implementations should be built, regardless of whether the
<code>RowSet</code> objects exist in a connected or disconnected environment.
The <tt>BaseRowSet</tt> abstract class provides any <tt>RowSet</tt> implementation
with its base functionality, including property manipulation and event notification
that is fully compliant with <a href="http://java.sun.com/products/javabeans">JavaBeans</a> 
component requirements. As an example, all implementations provided in the
reference implementations (contained in the <tt>com.sun.rowset</tt> package) use
the <tt>BaseRowSet</tt> class as a basis for their implementations.            
<P>
The following table illustrates the features that the <code>BaseRowSet</code>
abstract class provides.
  <blockquote>                    
    <table cellpadding="2" cellspacing="2" border="1" width="75%">
          <tbody>
            <tr>
              <td valign="top"><b>Feature</b><br>
              </td>
              <td valign="top"><b>Details</b><br>
              </td>
            </tr>
            <tr>
              <td valign="top">Properties<br>
              </td>
              <td valign="top">Provides standard JavaBeans property manipulation
  mechanisms to allow applications to get and set <code>RowSet</code> command and
property  values. Refer to the   documentation of the <tt>javax.sql.RowSet</tt>
interface  (available in the JDBC 3.0 specification) for more details on
the standard  <code>RowSet</code> properties.<br>
              </td>
            </tr>
            <tr>
              <td valign="top">Event notification<br>
              </td>
              <td valign="top">Provides standard JavaBeans event notifications
  to registered event listeners. Refer to the documentation of <tt>javax.sql.RowSetEvent
           </tt> interface (available in the JDBC 3.0 specification) for
more  details on how  to register and handle standard RowSet events generated
by  compliant implementations.<br>
              </td>
            </tr>
            <tr>
              <td valign="top">Setters for a RowSet object's command<br>
              </td>
              <td valign="top">Provides a complete set of setter methods
                 for setting RowSet command parameters.<br>
              </td>
            </tr>
            <tr>
              <td valign="top">Streams<br>
              </td>
              <td valign="top">Provides fields for storing of stream instances
  in addition to providing a set of constants for stream type designation.<br>
              </td>
            </tr>
                               
      </tbody>                    
    </table>
    </blockquote>
<p>
<li><b>3.3 Connected RowSet Requirements</b>
<p>
The <code>JdbcRowSet</code> describes a <code>RowSet</code> object that <b>must</b> always
be connected to the originating data source. Implementations of the <code>JdbcRowSet</code>
should ensure that this connection is provided solely by a JDBC driver. 
Furthermore, <code>RowSet</code> objects that are implementations of the 
<code>JdbcRowSet</code> interface and are therefore operating in a connected environment
do not use the <code>SyncFactory</code> to obtain a <code>RowSetReader</code> object
or a <code>RowSetWriter</code> object. They can safely rely on the JDBC driver to
supply their needs by virtue of the presence of an underlying updatable and scrollable
<code>ResultSet</code> implementation.
<p>

<li>
<b>3.4 Disconnected RowSet Requirements</b>
<p> 
A disconnected <code>RowSet</code> object, such as a <code>CachedRowSet</code> object, 
<b>should</b> delegate  
connection management to a <code>SyncProvider</code> object provided by the 
<code>SyncFactory</code>. To ensure fully disconnected semantics, all 
disconnected <code>RowSet</code> objects <b>must</b> ensure
that the original connection made to the data source to populate the <code>RowSet</code> 
object is closed to permit the garbage collector to recover and release resources. The
<code>SyncProvider</code> object ensures that the critical JDBC properties are 
maintained in order to re-establish a connection to the data source when a 
synchronization is required. A disconnected <code>RowSet</code> object should 
therefore ensure that no 
extraneous references remain on the <code>Connection</code> object.
<p>
<li><b>3.5 Role of RowSetMetaDataImpl</b>
<p>
The <code>RowsetMetaDataImpl</code> class is a utility class that provides an implementation of the
<a href="../RowSetMetaData.html">RowSetMetaData</a> interface, supplying standard setter
method implementations for metadata for both connected and disconnected 
<code>RowSet</code> objects. All implementations are free to use this standard
implementation but are not required to do so.
<p>
<li><b>3.6 RowSetWarning Class</b>
<p>
The <code>RowSetWarning</code> class provides warnings that can be set
on <code>RowSet</code> implementations.
Similar to <a href="../../../java/sql/SQLWarning.html">SQLWarning</a> objects,
<code>RowSetWarning</code>  objects are silently chained to the object whose method
caused the warning to be thrown. All <code>RowSet</code> implementations <b>should</b>  
ensure that this chaining occurs if a warning is generated and also ensure that the
warnings are available via the <code>getRowSetWarnings</code> method defined in either
the <code>JdbcRowSet</code> interface or the <code>CachedRowSet</code> interface. 
After a warning has been retrieved with one of the
<code>getRowSetWarnings</code> methods, the <code>RowSetWarning</code> method
<code>getNextWarning</code> can be called on it to retrieve any warnings that might
be chained on it.  If a warning is returned, <code>getNextWarning</code> can be called
on it, and so on until there are no more warnings.


<P>
<li><b>3.7 The Joinable Interface</b>
<P>
The <code>Joinable</code> interface provides both connected and disconnected 
<code>RowSet</code> objects with the capability to be added to a 
<code>JoinRowSet</code> object in an SQL <code>JOIN</code> operation.
A <code>RowSet</code> object that has  implemented the <code>Joinable</code> 
interface can set a match column, retrieve a match column, or unset a match column.
A <code>JoinRowSet</code> object can then use the <code>RowSet</code> object's
match column as a basis for adding the <code>RowSet</code> object.
</li>

<li><b>3.8 The RowSetFactory Interface</b>
    <p>
        A <code>RowSetFactory</code> implementation <strong>must</strong>
        be provided.
</li>
</ul>

<h3><a name="relspec">4.0 Related Specifications</a></h3>
<ul>
<li><a href="http://java.sun.com/products/jdbc">JDBC 3.0 Specification</a>
<li><a href="http://www.w3.org/XML/Schema">XML Schema</a>
<li><a href="http://www.syncml.org">SyncML</a>
</ul>

<h3><a name="reldocs">5.0 Related Documentation</a></h3>
<ul>
<li><a href="http://java.sun.com/developer/Books/JDBCTutorial/chapter5.html">
JDBC RowSet Tutorial</a>      
</ul>
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