libdb/docs/collections/tutorial/tuple-serialentitybindings.html

199 lines
8.5 KiB
HTML
Raw Normal View History

2011-09-13 17:44:24 +00:00
<?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>Creating Tuple-Serial Entity Bindings</title>
<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
<link rel="start" href="index.html" title="Berkeley DB Collections Tutorial" />
<link rel="up" href="Tuple.html" title="Chapter 5.  Using Tuples" />
<link rel="prev" href="tuplekeybindings.html" title="Creating Tuple Key Bindings" />
<link rel="next" href="sortedcollections.html" title="Using Sorted Collections" />
</head>
<body>
<div xmlns="" class="navheader">
<div class="libver">
<p>Library Version 11.2.5.2</p>
</div>
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">
Creating Tuple-Serial Entity Bindings
</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="tuplekeybindings.html">Prev</a> </td>
<th width="60%" align="center">Chapter 5. 
Using Tuples
</th>
<td width="20%" align="right"> <a accesskey="n" href="sortedcollections.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="tuple-serialentitybindings"></a>
Creating Tuple-Serial Entity Bindings
</h2>
</div>
</div>
</div>
<p>
In the prior example serial keys and serial values were used,
and the
<a class="ulink" href="../../java/com/sleepycat/bind/serial/SerialSerialBinding.html" target="_top">SerialSerialBinding</a>
base class was used for entity bindings. In this example, tuple
keys and serial values are used and therefore the
<a class="ulink" href="../../java/com/sleepycat/bind/serial/TupleSerialBinding.html" target="_top">TupleSerialBinding</a>
base class is used for entity bindings.
</p>
<p>
As with any entity binding, a key and value is converted to an
entity in the
<a class="ulink" href="../../java/com/sleepycat/bind/serial/TupleSerialBinding.html#entryToObject(com.sleepycat.bind.tuple.TupleInput,%20java.lang.Object)" target="_top">TupleSerialBinding.entryToObject</a>
method, and from an entity to
a key and value in the
<a class="ulink" href="../../java/com/sleepycat/bind/serial/TupleSerialBinding.html#objectToKey(java.lang.Object,%20com.sleepycat.db.DatabaseEntry)" target="_top">TupleSerialBinding.objectToKey</a>
and
<a class="ulink" href="../../java/com/sleepycat/bind/serial/TupleSerialBinding.html#objectToData(java.lang.Object)" target="_top">TupleSerialBinding.objectToData</a>
methods. But since keys are
stored as tuples, not as serialized objects, key fields are read
and written using the
<a class="ulink" href="../../java/com/sleepycat/bind/tuple/TupleInput.html" target="_top">TupleInput</a>
and
<a class="ulink" href="../../java/com/sleepycat/bind/tuple/TupleOutput.html" target="_top">TupleOutput</a>
parameters.
</p>
<p>
The <code class="classname">SampleViews</code> class contains the modified entity
binding classes that were defined in the prior example:
<code class="classname">PartBinding</code>, <code class="classname">SupplierBinding</code> and
<code class="classname">ShipmentBinding</code>.
</p>
<a id="tuple_partbinding"></a>
<pre class="programlisting"><strong class="userinput"><code>import com.sleepycat.bind.serial.TupleSerialBinding;
import com.sleepycat.bind.tuple.TupleInput;
import com.sleepycat.bind.tuple.TupleOutput;
...</code></strong>
public class SampleViews
{
...
private static class PartBinding extends <strong class="userinput"><code>TupleSerialBinding</code></strong>
{
private PartBinding(ClassCatalog classCatalog, <strong class="userinput"><code>Class dataClass</code></strong>)
{
super(classCatalog, dataClass);
}
public Object entryToObject(<strong class="userinput"><code>TupleInput</code></strong> keyInput, Object dataInput)
{
<strong class="userinput"><code> String number = keyInput.readString();</code></strong>
PartData data = (PartData) dataInput;
return new Part(<strong class="userinput"><code>number</code></strong>, data.getName(), data.getColor(),
data.getWeight(), data.getCity());
}
public void objectToKey(Object object, TupleOutput output)
{
Part part = (Part) object;
<strong class="userinput"><code> output.writeString(part.getNumber());</code></strong>
}
public Object objectToData(Object object)
{
Part part = (Part) object;
return new PartData(part.getName(), part.getColor(),
part.getWeight(), part.getCity());
}
}
...
private static class SupplierBinding extends <strong class="userinput"><code>TupleSerialBinding</code></strong>
{
private SupplierBinding(ClassCatalog classCatalog, <strong class="userinput"><code>Class dataClass</code></strong>)
{
super(classCatalog, dataClass);
}
public Object entryToObject(<strong class="userinput"><code>TupleInput</code></strong> keyInput, Object dataInput)
{
<strong class="userinput"><code> String number = keyInput.readString();</code></strong>
SupplierData data = (SupplierData) dataInput;
return new Supplier(<strong class="userinput"><code>number</code></strong>, data.getName(),
data.getStatus(), data.getCity());
}
public void objectToKey(Object object, TupleOutput output)
{
Supplier supplier = (Supplier) object;
<strong class="userinput"><code> output.writeString(supplier.getNumber());</code></strong>
}
public Object objectToData(Object object)
{
Supplier supplier = (Supplier) object;
return new SupplierData(supplier.getName(),
supplier.getStatus(),
supplier.getCity());
}
}
...
private static class ShipmentBinding extends <strong class="userinput"><code>TupleSerialBinding</code></strong>
{
private ShipmentBinding(ClassCatalog classCatalog, <strong class="userinput"><code>Class dataClass</code></strong>)
{
super(classCatalog, dataClass);
}
public Object entryToObject(<strong class="userinput"><code>TupleInput</code></strong> keyInput, Object dataInput)
{
<strong class="userinput"><code> String partNumber = keyInput.readString();
String supplierNumber = keyInput.readString();</code></strong>
ShipmentData data = (ShipmentData) dataInput;
return new Shipment(<strong class="userinput"><code>partNumber, supplierNumber</code></strong>,
data.getQuantity());
}
public void objectToKey(Object object, TupleOutput output)
{
Shipment shipment = (Shipment) object;
<strong class="userinput"><code> output.writeString(shipment.getPartNumber());
output.writeString(shipment.getSupplierNumber());</code></strong>
}
public Object objectToData(Object object)
{
Shipment shipment = (Shipment) object;
return new ShipmentData(shipment.getQuantity());
}
}
...
} </pre>
</div>
<div class="navfooter">
<hr />
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left"><a accesskey="p" href="tuplekeybindings.html">Prev</a> </td>
<td width="20%" align="center">
<a accesskey="u" href="Tuple.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="sortedcollections.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">
Creating Tuple Key Bindings
 </td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
</td>
<td width="40%" align="right" valign="top"> 
Using Sorted Collections
</td>
</tr>
</table>
</div>
</body>
</html>