131 lines
4.9 KiB
HTML
131 lines
4.9 KiB
HTML
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
|
||
<!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">
|
||
<head>
|
||
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
|
||
<title>
|
||
Removing the Redundant Value Classes
|
||
</title>
|
||
<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
|
||
<meta name="generator" content="DocBook XSL Stylesheets V1.62.4" />
|
||
<link rel="home" href="index.html" title="Berkeley DB Collections Tutorial" />
|
||
<link rel="up" href="SerializableEntity.html" title="Chapter 6. 		Using Serializable Entities 	" />
|
||
<link rel="previous" href="transientfieldsinbinding.html" title=" 		Using Transient Fields in an Entity Binding 	" />
|
||
<link rel="next" href="Summary.html" title="Chapter 7. 		Summary 	" />
|
||
</head>
|
||
<body>
|
||
<div class="navheader">
|
||
<table width="100%" summary="Navigation header">
|
||
<tr>
|
||
<th colspan="3" align="center">
|
||
Removing the Redundant Value Classes
|
||
</th>
|
||
</tr>
|
||
<tr>
|
||
<td width="20%" align="left"><a accesskey="p" href="transientfieldsinbinding.html">Prev</a> </td>
|
||
<th width="60%" align="center">Chapter 6.
|
||
Using Serializable Entities
|
||
</th>
|
||
<td width="20%" align="right"> <a accesskey="n" href="Summary.html">Next</a></td>
|
||
</tr>
|
||
</table>
|
||
<hr />
|
||
</div>
|
||
<div class="sect1" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h2 class="title" style="clear: both"><a id="removingredundantvalueclasses"></a>
|
||
Removing the Redundant Value Classes
|
||
</h2>
|
||
</div>
|
||
</div>
|
||
<div></div>
|
||
</div>
|
||
<p>
|
||
The <tt class="classname">PartData</tt>, <tt class="classname">SupplierData</tt> and <tt class="classname">ShipmentData</tt>
|
||
classes have been removed in this example, and the <tt class="classname">Part</tt>,
|
||
<tt class="classname">Supplier</tt> and <tt class="classname">Shipment</tt> entity classes are used in
|
||
their place.
|
||
</p>
|
||
<p>
|
||
The serial formats are created with the entity classes.
|
||
</p>
|
||
<a id="sentity_sampledatabase"></a>
|
||
<pre class="programlisting">public class SampleDatabase
|
||
{
|
||
...
|
||
public SampleDatabase(String homeDirectory)
|
||
throws DatabaseException, FileNotFoundException
|
||
{
|
||
...
|
||
secConfig.setKeyCreator(new SupplierByCityKeyCreator(javaCatalog,
|
||
<b class="userinput"><tt>Supplier</tt></b>.class));
|
||
...
|
||
secConfig.setKeyCreator(new ShipmentByPartKeyCreator(javaCatalog,
|
||
<b class="userinput"><tt>Shipment</tt></b>.class));
|
||
...
|
||
secConfig.setKeyCreator(new ShipmentBySupplierKeyCreator(javaCatalog,
|
||
<b class="userinput"><tt>Shipment</tt></b>.class));
|
||
...
|
||
}
|
||
} </pre>
|
||
<p>
|
||
The index key creator uses the entity class as well.
|
||
</p>
|
||
<a id="sentity_supplierbycitykeycreator"></a>
|
||
<pre class="programlisting">public class SampleDatabase
|
||
{
|
||
...
|
||
|
||
private static class SupplierByCityKeyCreator
|
||
extends TupleSerialKeyCreator
|
||
{
|
||
private SupplierByCityKeyCreator(ClassCatalog catalog,
|
||
Class valueClass)
|
||
{
|
||
super(catalog, valueClass);
|
||
}
|
||
|
||
public boolean createSecondaryKey(TupleInput primaryKeyInput,
|
||
Object valueInput,
|
||
TupleOutput indexKeyOutput)
|
||
{
|
||
<b class="userinput"><tt>Supplier</tt></b> supplier = (<b class="userinput"><tt>Supplier</tt></b>) valueInput;
|
||
String city = supplier.getCity();
|
||
if (city != null) {
|
||
indexKeyOutput.writeString(supplier.getCity());
|
||
return true;
|
||
} else {
|
||
return false;
|
||
}
|
||
}
|
||
}
|
||
} </pre>
|
||
</div>
|
||
<div class="navfooter">
|
||
<hr />
|
||
<table width="100%" summary="Navigation footer">
|
||
<tr>
|
||
<td width="40%" align="left"><a accesskey="p" href="transientfieldsinbinding.html">Prev</a> </td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="u" href="SerializableEntity.html">Up</a>
|
||
</td>
|
||
<td width="40%" align="right"> <a accesskey="n" href="Summary.html">Next</a></td>
|
||
</tr>
|
||
<tr>
|
||
<td width="40%" align="left" valign="top">
|
||
Using Transient Fields in an Entity Binding
|
||
</td>
|
||
<td width="20%" align="center">
|
||
<a accesskey="h" href="index.html">Home</a>
|
||
</td>
|
||
<td width="40%" align="right" valign="top"> Chapter 7.
|
||
Summary
|
||
</td>
|
||
</tr>
|
||
</table>
|
||
</div>
|
||
</body>
|
||
</html>
|