blob: 49c2cf23ad034952573c51a421116447593c392d [file] [log] [blame]
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii" />
<meta http-equiv="Content-Style-Type" content="text/css" />
<meta http-equiv="Content-Script-Type" content="text/javascript" />
<title>Object-XML Descriptor Concepts | EclipseLink 2.5.x Understanding EclipseLink</title>
<meta name="generator" content="Oracle DARB XHTML Converter (Mode = document) - Version 1.0.17" />
<meta name="date" content="2013-10-03T10:37:15Z" />
<meta name="robots" content="noarchive" />
<meta name="doctitle" content="Object-XML Descriptor Concepts" />
<meta name="relnum" content="2.5" />
<link rel="stylesheet" type="text/css" href="../../dcommon/style.css" media="screen" />
<link rel="copyright" href="../../dcommon/html/cpyr.htm" title="Copyright" type="text/html" />
<link rel="start" href="../../index.htm" title="Home" type="text/html" />
<link rel="contents" href="toc.htm" title="Contents" type="text/html" />
<link rel="prev" href="descriptors002.htm" title="Previous" type="text/html" />
<link rel="next" href="descriptors004.htm" title="Next" type="text/html" />
<!-- START: Disqus --><script type="text/javascript"> var disqus_developer = 0; </script><!-- END: Disqus --><!-- START: Sharethis --><script type="text/javascript">var switchTo5x=true;</script><script type="text/javascript" src="http://w.sharethis.com/button/buttons.js"></script><script type="text/javascript" src="http://s.sharethis.com/loader.js"></script> <!-- END: Sharethis --></head>
<body bgcolor="#FFFFFF"><iframe id="docheader" frameborder="0" framemargin="0" scrolling="no" src="../../dcommon/header.html"></iframe><script src="http://www.google.com/jsapi" type="text/javascript"></script><script type="text/javascript"> google.load('search', '1', {language : 'en'}); google.setOnLoadCallback(function() { var customSearchOptions = {}; var googleAnalyticsOptions = {}; googleAnalyticsOptions['queryParameter'] = 'q'; googleAnalyticsOptions['categoryParameter'] = ''; customSearchOptions['googleAnalyticsOptions'] = googleAnalyticsOptions; var customSearchControl = new google.search.CustomSearchControl( '016171230611334810008:mdbgdwjv8zu', customSearchOptions); customSearchControl.setResultSetSize(google.search.Search.FILTERED_CSE_RESULTSET); var options = new google.search.DrawOptions(); options.setSearchFormRoot('cse-search-form'); customSearchControl.draw('cse', options); }, true);</script><link rel="stylesheet" href="http://www.google.com/cse/style/look/default.css" type="text/css" /><div id="cse" style="width:100%;"></div>
<div class="header"><a id="top" name="top"></a>
<table class="simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100%">
<tr>
<td align="left" valign="top"><div class="booktitle">Understanding EclipseLink,
<b>2.5</b><br /></font></td>
<td valign="bottom" align="right" width="144">
<table class="simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100%">
<tr>
<td>&nbsp;</td>
<td align="center" valign="top"><a href="toc.htm"><img src="../../dcommon/images/contents.png" alt="Go To Table Of Contents" border="0" height="16" width="16" /><br />
</td><td>&nbsp;</td><td align="center"><a href="../../" target="_top" class="external text" title="Search" rel="nofollow"><img src="../../dcommon/images/search.png" alt="Search" style="border:0;" /><br /><span class="mini"></span></a></td><td>&nbsp;</td><td align="center"><a href="../eclipselink_otlcg.pdf" title="PDF" target="_blank"><img src="../../dcommon/images/pdf_icon.png" style="padding-right:5px;border:0" alt="PDF"></a></td>
</tr>
</table>
</td>
</tr>
</table>
<hr />
<table class="navigation simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100" align="center">
<tr>
<td align="center"><a href="descriptors002.htm"><img src="../../dcommon/images/larrow.png" alt="Previous" border="0" height="16" width="16" /></a></td>
<td align="center"><a href="descriptors004.htm"><img src="../../dcommon/images/rarrow.png" alt="Next" border="0" height="16" width="16" /></a></td>
<td>&nbsp;</td>
</tr>
</table>
</div>
<!-- class="header" -->
<div class="ind"><!-- End Header --><a id="CHDHJDAD" name="CHDHJDAD"></a>
<div class="sect1"><!-- infolevel="all" infotype="General" -->
<h1 class="sect1"><font face="arial, helvetica, sans-serif" color="#330099">Object-XML Descriptor Concepts</font></h1>
<p>The following section describes the use of default root elements in Object-XML descriptors.</p>
<a id="CHEIGDGI" name="CHEIGDGI"></a><a id="OTLCG92067" name="OTLCG92067"></a>
<div class="sect2"><!-- infolevel="all" infotype="General" -->
<h2 class="sect2"><font face="arial, helvetica, sans-serif" color="#330099">Default Root Element</font></h2>
<p>You configure XML descriptors with a default root element so that the EclipseLink runtime knows the data source data type associated with the class the descriptor describes.</p>
<div align="center">
<div class="inftblnote"><br />
<table class="Note oac_no_warn" summary="" border="1" width="80%" frame="hsides" rules="groups" cellpadding="3" cellspacing="0">
<tbody>
<tr>
<td align="left">
<p class="note"><img src="../../dcommon/images/note_icon.png" width="16" height="16" alt="Note" style="vertical-align:middle;padding-right:5px;" />Note:</p>
<p>The undefined document root element of a referenced object is ignored during marshalling with an any collection mapping and object mapping.</p>
</td>
</tr>
</tbody>
</table>
<br /></div>
<!-- class="inftblnote" --></div>
<p>This section describes what a default root element is and how EclipseLink uses it.</p>
<p>Consider the <code>Customer</code> and <code>Address</code> classes and their mappings, shown in <a href="#CHEIIJHF">Example 6-2</a>.</p>
<div class="example"><a id="CHEIIJHF" name="CHEIIJHF"></a><a id="OTLCG92068" name="OTLCG92068"></a>
<p><strong><em><font face="arial, helvetica, sans-serif">Example 6-2 Customer and Address Classes</font></em></strong></p>
<pre xml:space="preserve" class="oac_no_warn">
<strong><code>Class:</code></strong> Customer
<strong><code>Default Root:</code></strong> customer
<strong><code>Attributes and Mappings:</code></strong>
name:String Direct Mapping name/text()
billingAddress:Address Composite Object Mapping to billing-address
shippingAddress:Address Composite Object Mapping to shipping-address
<strong><code>Class:</code></strong> Address
<strong><code>Default Root:</code></strong> address
<strong><code>Attributes and Mappings:</code></strong>
street:String Direct Mapping to street/text()
city:String Direct Mapping to city/text()
</pre></div>
<!-- class="example" -->
<p>These classes correspond to the XML schema, shown in <a href="#CHEDADEA">Example 6-3</a>.</p>
<div class="example"><a id="CHEDADEA" name="CHEDADEA"></a><a id="OTLCG92069" name="OTLCG92069"></a>
<p><strong><em><font face="arial, helvetica, sans-serif">Example 6-3 Customer and Address Schema</font></em></strong></p>
<pre xml:space="preserve" class="oac_no_warn">
&lt;xsd:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"&gt;
&lt;xsd:complexType name="address-type"&gt;
&lt;xsd:sequence&gt;
&lt;element name="street" type="xsd:string"/&gt;
&lt;element name="city" type="xsd:string"/&gt;
&lt;/xsd:sequence&gt;
&lt;/xsd:complexType&gt;
&lt;xsd:element name="customer" type="customer-type"/&gt;
&lt;xsd:complexType name="customer-type"&gt;
&lt;xsd:sequence&gt;
&lt;xsd:element name="name" type="xsd:string"/&gt;
&lt;xsd:element name="billing-address" type="address-type"/&gt;
&lt;xsd:element name="shipping-address" type="address-type"/&gt;
&lt;/xsd:sequence&gt;
&lt;/xsd:complexType&gt;
&lt;/xsd:schema&gt;
</pre></div>
<!-- class="example" -->
<p>When an instance of the <code>Customer</code> class is persisted to XML, the EclipseLink runtime performs the following:</p>
<ol>
<li>
<p>Gets the default root element.</p>
<p>The <code>Customer</code> class instance corresponds to the root of the XML document. The EclipseLink runtime uses the default root element specified on the descriptor (<code>customer</code>) to start the XML document. EclipseLink then uses the mappings on the descriptor to marshal the object's attributes:</p>
<pre xml:space="preserve" class="oac_no_warn">
&lt;customer&gt;
&lt;name&gt;&hellip;&lt;/name&gt;
&lt;/customer&gt;
</pre></li>
<li>
<p>When the EclipseLink runtime encounters an object attribute such as <code>billingAddress</code>, it checks the mapping associated with it to determine with what element (<code>billing-address</code>) to continue:</p>
<pre xml:space="preserve" class="oac_no_warn">
&lt;customer&gt;
&lt;name&gt;&hellip;&lt;/name&gt;
&lt;billing-address/&gt;
&lt;/customer&gt;
</pre>
<p>The EclipseLink runtime checks the mapping's reference descriptor (<code>Address</code>) to determine what attributes to persist:</p>
<pre xml:space="preserve" class="oac_no_warn">
&lt;customer&gt;
&lt;name&gt;&hellip;&lt;/name&gt;
&lt;billing-address&gt;
&lt;street&gt;&hellip;&lt;/street&gt;
&lt;city&gt;&hellip;&lt;/city&gt;
&lt;/billing-address&gt;
&lt;/customer&gt;
</pre></li>
</ol>
</div>
<!-- class="sect2" --></div>
<!-- class="sect1" --></div>
<!-- class="ind" -->
<!-- Start Footer -->
<div class="footer">
<hr />
<table class="simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100%">
<col width="33%" />
<col width="*" />
<col width="33%" />
<tr>
<td valign="bottom">
<table class="navigation simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100" align="center">
<col width="*" />
<col width="48%" />
<col width="48%" />
<tr>
<td>&nbsp;</td>
<td align="center"><a href="descriptors002.htm"><img src="../../dcommon/images/larrow.png" alt="Previous" border="0" height="16" width="16" /></a></td>
<td align="center"><a href="descriptors004.htm"><img src="../../dcommon/images/rarrow.png" alt="Next" border="0" height="16" width="16" /></a></td>
</tr>
</table>
</td>
<td align="center" width="34%"><a href="http://www.eclipse.org/eclipselink/" title="EclipseLink home"><img src="../../dcommon/images/ellogo.png" alt="EclipseLink" width="150" border="0" /></a><br />
<td valign="bottom" align="right">
<table class="simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="225">
<tr>
<td>&nbsp;</td>
<td align="center" valign="top"><a href="toc.htm"><img src="../../dcommon/images/contents.png" alt="Go To Table Of Contents" border="0" height="16" width="16" /><br />
</td><td>&nbsp;</td><td align="center"><a href="../../" target="_top" class="external text" title="Search" rel="nofollow"><img src="../../dcommon/images/search.png" alt="Search" style="border:0;" /><br /><span class="mini"></span></a></td><td>&nbsp;</td><td align="center"><a href="../eclipselink_otlcg.pdf" title="PDF" target="_blank"><img src="../../dcommon/images/pdf_icon.png" style="padding-right:5px;border:0" alt="PDF"></a></td>
</tr>
</table>
</td>
</tr>
</table>
</div>
<!-- class="footer" -->
<div id="copyright">Copyright &copy; 2012 by The Eclipse Foundation under the <a href="http://www.eclipse.org/org/documents/epl-v10.php">Eclipse Public License (EPL)</a><br /> <script type="text/javascript">var LastUpdated = document.lastModified;document.writeln ("Updated: " + LastUpdated);</script> </div><!-- START: Analytics --><script type="text/javascript"> var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-1608008-2']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); </script><!-- END: Analytics --><!-- START: Sharethis --><script>var options={ "publisher": "e2fe9e07-fab6-4f84-83ea-0991b429842c", "position": "right", "ad": { "visible": false, "openDelay": 5, "closeDelay": 0}};var st_hover_widget = new sharethis.widgets.hoverbuttons(options);</script><!-- END: Sharethis --></body>
</html>