1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
<?xml version="1.0" encoding="ISO-8859-1" 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=ISO-8859-1" />
<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="Chapter6. 		Using Serializable Entities 	" />
<link rel="previous" href="transientfieldsinbinding.html" title=" 		Using Transient Fields in an Entity Binding 	" />
<link rel="next" href="Summary.html" title="Chapter7. 		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">Chapter6.
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">Chapter7.
Summary
</td>
</tr>
</table>
</div>
</body>
</html>
|
