mirror of
https://github.com/berkeleydb/libdb.git
synced 2024-11-17 01:26:25 +00:00
221 lines
8.3 KiB
HTML
221 lines
8.3 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>Creating Tuple Key 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="tupleswithkeycreators.html" title="Using Tuples with Key Creators" />
|
|||
|
|
<link rel="next" href="tuple-serialentitybindings.html" title="Creating Tuple-Serial Entity Bindings" />
|
|||
|
|
</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 Key Bindings
|
|||
|
|
</th>
|
|||
|
|
</tr>
|
|||
|
|
<tr>
|
|||
|
|
<td width="20%" align="left"><a accesskey="p" href="tupleswithkeycreators.html">Prev</a> </td>
|
|||
|
|
<th width="60%" align="center">Chapter 5.
|
|||
|
|
Using Tuples
|
|||
|
|
</th>
|
|||
|
|
<td width="20%" align="right"> <a accesskey="n" href="tuple-serialentitybindings.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="tuplekeybindings"></a>
|
|||
|
|
Creating Tuple Key Bindings
|
|||
|
|
</h2>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<p>
|
|||
|
|
Serial bindings were used in prior examples as key bindings, and
|
|||
|
|
keys were stored as serialized objects. In this example, a tuple
|
|||
|
|
binding is used for each key since keys will be stored as tuples.
|
|||
|
|
Because keys are no longer stored as serialized objects, the
|
|||
|
|
<code class="classname">PartKey</code>, <code class="classname">SupplierKey</code> and <code class="classname">ShipmentKey</code> classes
|
|||
|
|
no longer implement the
|
|||
|
|
<a class="ulink" href="http://download.oracle.com/javase/1.5.0/docs/api/java/io/Serializable.html" target="_top">Serializable</a>
|
|||
|
|
|
|||
|
|
interface (this is the only change to these classes and is not
|
|||
|
|
shown below).
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
For the <code class="classname">Part</code> key, <code class="classname">Supplier</code> key,
|
|||
|
|
and <code class="classname">Shipment</code> key, the
|
|||
|
|
<code class="classname">SampleViews</code> class was changed in this example to create a
|
|||
|
|
custom
|
|||
|
|
<a class="ulink" href="../../java/com/sleepycat/bind/tuple/TupleBinding.html" target="_top">TupleBinding</a>
|
|||
|
|
|
|||
|
|
instead of a
|
|||
|
|
<a class="ulink" href="../../java/com/sleepycat/bind/serial/SerialBinding.html" target="_top">SerialBinding</a>.
|
|||
|
|
The custom tuple key binding classes are defined further below.
|
|||
|
|
</p>
|
|||
|
|
<a id="tuple_sampleviews"></a>
|
|||
|
|
<pre class="programlisting"><strong class="userinput"><code>import com.sleepycat.bind.tuple.TupleBinding;
|
|||
|
|
...</code></strong>
|
|||
|
|
public class SampleViews
|
|||
|
|
{
|
|||
|
|
...
|
|||
|
|
public SampleViews(SampleDatabase db)
|
|||
|
|
{
|
|||
|
|
...
|
|||
|
|
ClassCatalog catalog = db.getClassCatalog();
|
|||
|
|
<strong class="userinput"><code> EntryBinding partKeyBinding =
|
|||
|
|
new PartKeyBinding();
|
|||
|
|
EntityBinding partDataBinding =
|
|||
|
|
new PartBinding(catalog, PartData.class);
|
|||
|
|
EntryBinding supplierKeyBinding =
|
|||
|
|
new SupplierKeyBinding();
|
|||
|
|
EntityBinding supplierDataBinding =
|
|||
|
|
new SupplierBinding(catalog, SupplierData.class);
|
|||
|
|
EntryBinding shipmentKeyBinding =
|
|||
|
|
new ShipmentKeyBinding();
|
|||
|
|
EntityBinding shipmentDataBinding =
|
|||
|
|
new ShipmentBinding(catalog, ShipmentData.class);
|
|||
|
|
EntryBinding cityKeyBinding =
|
|||
|
|
TupleBinding.getPrimitiveBinding(String.class);</code></strong>
|
|||
|
|
...
|
|||
|
|
}
|
|||
|
|
} </pre>
|
|||
|
|
<p>
|
|||
|
|
For the City key, however, a custom binding class is not needed
|
|||
|
|
because the key class is a primitive Java type,
|
|||
|
|
<a class="ulink" href="http://download.oracle.com/javase/1.5.0/docs/api/java/lang/String.html" target="_top">String</a>.
|
|||
|
|
For any primitive Java type, a tuple binding may be created using the
|
|||
|
|
<a class="ulink" href="../../java/com/sleepycat/bind/tuple/TupleBinding.html#getPrimitiveBinding(java.lang.Class)" target="_top">TupleBinding.getPrimitiveBinding</a>
|
|||
|
|
|
|||
|
|
static method.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
The custom key binding classes, <code class="classname">PartKeyBinding</code>,
|
|||
|
|
<code class="classname">SupplierKeyBinding</code> and <code class="classname">ShipmentKeyBinding</code>, are
|
|||
|
|
defined by extending the
|
|||
|
|
<a class="ulink" href="../../java/com/sleepycat/bind/tuple/TupleBinding.html" target="_top">TupleBinding</a>
|
|||
|
|
|
|||
|
|
class. The
|
|||
|
|
<a class="ulink" href="../../java/com/sleepycat/bind/tuple/TupleBinding.html" target="_top">TupleBinding</a>
|
|||
|
|
|
|||
|
|
abstract class implements the
|
|||
|
|
<a class="ulink" href="../../java/com/sleepycat/bind/EntryBinding.html" target="_top">EntryBinding</a>
|
|||
|
|
|
|||
|
|
interface, and is used for one-to-one bindings between tuples and
|
|||
|
|
objects. Each binding class implements two methods for converting
|
|||
|
|
between tuples and objects. Tuple fields are read using the
|
|||
|
|
<a class="ulink" href="../../java/com/sleepycat/bind/tuple/TupleInput.html" target="_top">TupleInput</a>
|
|||
|
|
|
|||
|
|
parameter and written using the
|
|||
|
|
<a class="ulink" href="../../java/com/sleepycat/bind/tuple/TupleOutput.html" target="_top">TupleOutput</a>
|
|||
|
|
|
|||
|
|
parameter.
|
|||
|
|
</p>
|
|||
|
|
<a id="tuple_partkeybinding"></a>
|
|||
|
|
<pre class="programlisting"><strong class="userinput"><code>import com.sleepycat.bind.tuple.TupleBinding;
|
|||
|
|
import com.sleepycat.bind.tuple.TupleInput;
|
|||
|
|
import com.sleepycat.bind.tuple.TupleOutput;
|
|||
|
|
...</code></strong>
|
|||
|
|
public class SampleViews
|
|||
|
|
{
|
|||
|
|
...
|
|||
|
|
|
|||
|
|
<strong class="userinput"><code>private static class PartKeyBinding extends TupleBinding
|
|||
|
|
{
|
|||
|
|
private PartKeyBinding()
|
|||
|
|
{
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public Object entryToObject(TupleInput input)
|
|||
|
|
{
|
|||
|
|
String number = input.readString();
|
|||
|
|
return new PartKey(number);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public void objectToEntry(Object object, TupleOutput output)
|
|||
|
|
{
|
|||
|
|
PartKey key = (PartKey) object;
|
|||
|
|
output.writeString(key.getNumber());
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
...
|
|||
|
|
private static class SupplierKeyBinding extends TupleBinding
|
|||
|
|
{
|
|||
|
|
private SupplierKeyBinding()
|
|||
|
|
{
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public Object entryToObject(TupleInput input)
|
|||
|
|
{
|
|||
|
|
String number = input.readString();
|
|||
|
|
return new SupplierKey(number);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public void objectToEntry(Object object, TupleOutput output)
|
|||
|
|
{
|
|||
|
|
SupplierKey key = (SupplierKey) object;
|
|||
|
|
output.writeString(key.getNumber());
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
...
|
|||
|
|
private static class ShipmentKeyBinding extends TupleBinding
|
|||
|
|
{
|
|||
|
|
private ShipmentKeyBinding()
|
|||
|
|
{
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public Object entryToObject(TupleInput input)
|
|||
|
|
{
|
|||
|
|
String partNumber = input.readString();
|
|||
|
|
String supplierNumber = input.readString();
|
|||
|
|
return new ShipmentKey(partNumber, supplierNumber);
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public void objectToEntry(Object object, TupleOutput output)
|
|||
|
|
{
|
|||
|
|
ShipmentKey key = (ShipmentKey) object;
|
|||
|
|
output.writeString(key.getPartNumber());
|
|||
|
|
output.writeString(key.getSupplierNumber());
|
|||
|
|
}
|
|||
|
|
}</code></strong>
|
|||
|
|
...
|
|||
|
|
} </pre>
|
|||
|
|
</div>
|
|||
|
|
<div class="navfooter">
|
|||
|
|
<hr />
|
|||
|
|
<table width="100%" summary="Navigation footer">
|
|||
|
|
<tr>
|
|||
|
|
<td width="40%" align="left"><a accesskey="p" href="tupleswithkeycreators.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="tuple-serialentitybindings.html">Next</a></td>
|
|||
|
|
</tr>
|
|||
|
|
<tr>
|
|||
|
|
<td width="40%" align="left" valign="top">
|
|||
|
|
Using Tuples with Key Creators
|
|||
|
|
</td>
|
|||
|
|
<td width="20%" align="center">
|
|||
|
|
<a accesskey="h" href="index.html">Home</a>
|
|||
|
|
</td>
|
|||
|
|
<td width="40%" align="right" valign="top">
|
|||
|
|
Creating Tuple-Serial Entity Bindings
|
|||
|
|
</td>
|
|||
|
|
</tr>
|
|||
|
|
</table>
|
|||
|
|
</div>
|
|||
|
|
</body>
|
|||
|
|
</html>
|