<!--$Id: remove.html,v 1.2 2004/03/30 01:22:46 jtownsen Exp $--> <!--Copyright 1997-2003 by Sleepycat Software, Inc.--> <!--All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB Reference Guide: Serializable Entity - Removing the redundant value classes</title> <meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> <meta name="keywords" content="embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> </head> <body bgcolor=white> <a name="2"><!--meow--></a> <table width="100%"><tr valign=top> <td><h3><dl><dt>Berkeley DB Reference Guide:<dd>Java API Tutorial - Serializable Entity</dl></h3></td> <td align=right><a href="../bdb_sentity/binding.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../bdb_tut/summary.html"><img src="../../images/next.gif" alt="Next"></a> </td></tr></table> <p> <h3 align=center>Serializable Entity - Removing the redundant value classes</h3> <p>The <b>PartValue</b>, <b>SupplierValue</b> and <b>ShipmentValue</b> classes have been removed in this example, and the <b>Part</b>, <b>Supplier</b> and <b>Shipment</b> entity classes are used in their place.</p> <hr size=1 noshade> <p>The serial formats are created with the entity classes.</p> <blockquote><pre> public class SampleDatabase { ... public SampleDatabase(String homeDirectory, boolean runRecovery) throws DbException, FileNotFoundException { ... partKeyFormat = new TupleFormat(); partValueFormat = new SerialFormat(javaCatalog, <b>Part</b>.class); supplierKeyFormat = new TupleFormat(); supplierValueFormat = new SerialFormat(javaCatalog, <b>Supplier</b>.class); shipmentKeyFormat = new TupleFormat(); shipmentValueFormat = new SerialFormat(javaCatalog, <b>Shipment</b>.class); cityKeyFormat = new TupleFormat(); ... } } </pre></blockquote> <hr size=1 noshade> <p>The index key extractor uses the entity class as well.</p> <blockquote><pre> public class SampleDatabase { ... private static class SupplierByCityExtractor extends TupleSerialKeyExtractor { private SupplierByCityExtractor(TupleFormat primaryKeyFormat, SerialFormat valueFormat, TupleFormat indexKeyFormat) { super(primaryKeyFormat, valueFormat, indexKeyFormat); } <p> public void extractIndexKey(TupleInput primaryKeyInput, Object valueInput, TupleOutput indexKeyOutput) throws IOException { <b>Supplier</b> supplierValue = (<b>Supplier</b>) valueInput; indexKeyOutput.writeString(supplierValue.getCity()); } <p> public void clearIndexKey(Object valueInputOutput) throws IOException { throw new UnsupportedOperationException(); } } <p> } </pre></blockquote> <table width="100%"><tr><td><br></td><td align=right><a href="../bdb_sentity/binding.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../bdb_tut/summary.html"><img src="../../images/next.gif" alt="Next"></a> </td></tr></table> <p><font size=1><a href="../../sleepycat/legal.html">Copyright (c) 1996-2003</a> <a href="http://www.sleepycat.com">Sleepycat Software, Inc.</a> - All rights reserved.</font> </body> </html>