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178 lines
6.3 KiB
HTML
178 lines
6.3 KiB
HTML
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
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<title>Using Transient Fields in an Entity Binding</title>
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<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
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<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
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<link rel="start" href="index.html" title="Berkeley DB Java Edition Collections Tutorial" />
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<link rel="up" href="SerializableEntity.html" title="Chapter 6. Using Serializable Entities" />
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<link rel="prev" href="SerializableEntity.html" title="Chapter 6. Using Serializable Entities" />
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<link rel="next" href="removingredundantvalueclasses.html" title="Removing the Redundant Value Classes" />
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</head>
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<body>
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<div xmlns="" class="navheader">
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<div class="libver">
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<p>Library Version 12.2.7.5</p>
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</div>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">
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Using Transient Fields in an Entity Binding
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</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="SerializableEntity.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 6.
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Using Serializable Entities
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="removingredundantvalueclasses.html">Next</a></td>
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</tr>
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</table>
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<hr />
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</div>
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<div class="sect1" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="transientfieldsinbinding"></a>
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Using Transient Fields in an Entity Binding
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</h2>
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</div>
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</div>
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</div>
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<p>
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The entity bindings from the prior example have been changed in
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this example to use the entity object both as a value object and an
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entity object.
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</p>
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<p>
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Before, the <code class="methodname">entryToObject()</code> method combined the
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deserialized value object with the key fields to create a new
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entity object. Now, this method uses the deserialized object
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directly as an entity, and initializes its key using the fields
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read from the key tuple.
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</p>
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<p>
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Before, the <code class="methodname">objectToData()</code> method constructed a new value
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object using information in the entity. Now it simply returns the
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entity. Nothing needs to be changed in the entity, since the
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transient key fields won't be serialized.
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</p>
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<a id="sentity_partbinding"></a>
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<pre class="programlisting">import com.sleepycat.bind.serial.ClassCatalog;
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...
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public class SampleViews
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{
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...
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private static class PartBinding extends TupleSerialBinding
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{
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private PartBinding(ClassCatalog classCatalog, Class dataClass)
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{
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super(classCatalog, dataClass);
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}
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public Object entryToObject(TupleInput keyInput, Object dataInput)
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{
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String number = keyInput.readString();
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<strong class="userinput"><code> Part part = (Part) dataInput;
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part.setKey(number);
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return part;</code></strong>
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}
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public void objectToKey(Object object, TupleOutput output)
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{
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Supplier supplier = (Supplier) object;
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output.writeString(supplier.getNumber());
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}
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public Object objectToData(Object object)
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{
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<strong class="userinput"><code> return object;</code></strong>
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}
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}
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private static class SupplierBinding extends TupleSerialBinding
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{
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private SupplierBinding(ClassCatalog classCatalog, Class dataClass)
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{
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super(classCatalog, dataClass);
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}
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public Object entryToObject(TupleInput keyInput, Object dataInput)
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{
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String number = keyInput.readString();
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<strong class="userinput"><code> Supplier supplier = (Supplier) dataInput;
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supplier.setKey(number);
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return supplier;</code></strong>
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}
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public void objectToKey(Object object, TupleOutput output)
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{
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Supplier supplier = (Supplier) object;
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output.writeString(supplier.getNumber());
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}
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public Object objectToData(Object object)
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{
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<strong class="userinput"><code> return object;</code></strong>
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}
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}
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private static class ShipmentBinding extends TupleSerialBinding
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{
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private ShipmentBinding(ClassCatalog classCatalog, Class dataClass)
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{
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super(classCatalog, dataClass);
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}
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public Object entryToObject(TupleInput keyInput, Object dataInput)
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{
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String partNumber = keyInput.readString();
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String supplierNumber = keyInput.readString();
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<strong class="userinput"><code> Shipment shipment = (Shipment) dataInput;
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shipment.setKey(partNumber, supplierNumber);
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return shipment;</code></strong>
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}
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public void objectToKey(Object object, TupleOutput output)
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{
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Shipment shipment = (Shipment) object;
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output.writeString(shipment.getPartNumber());
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output.writeString(shipment.getSupplierNumber());
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}
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public Object objectToData(Object object)
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{
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<strong class="userinput"><code> return object;</code></strong>
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}
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}
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} </pre>
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</div>
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<div class="navfooter">
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<hr />
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<table width="100%" summary="Navigation footer">
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||
<tr>
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||
<td width="40%" align="left"><a accesskey="p" href="SerializableEntity.html">Prev</a> </td>
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||
<td width="20%" align="center">
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<a accesskey="u" href="SerializableEntity.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="removingredundantvalueclasses.html">Next</a></td>
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</tr>
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<tr>
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<td width="40%" align="left" valign="top">Chapter 6.
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Using Serializable Entities
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</td>
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<td width="20%" align="center">
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<a accesskey="h" href="index.html">Home</a>
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</td>
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<td width="40%" align="right" valign="top">
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Removing the Redundant Value Classes
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</td>
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</tr>
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</table>
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</div>
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</body>
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</html>
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