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218 lines
8.6 KiB
HTML
218 lines
8.6 KiB
HTML
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<?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>Chapter 1. Introduction</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 Collections Tutorial" />
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<link rel="up" href="index.html" title="Berkeley DB Collections Tutorial" />
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<link rel="prev" href="moreinfo.html" title="For More Information" />
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<link rel="next" href="developing.html" title="Developing a DB Collections Application" />
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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 11.2.5.2</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">Chapter 1.
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Introduction
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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="moreinfo.html">Prev</a> </td>
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<th width="60%" align="center"> </th>
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<td width="20%" align="right"> <a accesskey="n" href="developing.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="chapter" 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"><a id="intro"></a>Chapter 1.
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Introduction
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</h2>
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</div>
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</div>
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</div>
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<div class="toc">
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<p>
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<b>Table of Contents</b>
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</p>
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<dl>
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<dt>
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<span class="sect1">
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<a href="intro.html#features">Features</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="developing.html">Developing a DB Collections Application</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="tutorialintroduction.html">Tutorial Introduction</a>
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</span>
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</dt>
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</dl>
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</div>
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<p>
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The DB Java Collections API is a Java framework that extends
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the well known
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<a class="ulink" href="http://download.oracle.com/javase/1.5.0/docs/guide/collections/" target="_top">Java Collections</a>
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design pattern such that collections can now be
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stored, updated and queried in a transactional manner. The
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DB Java Collections API is a layer on top of DB.
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</p>
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<p>
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Together the DB Java Collections API and Berkeley DB provide an
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embedded data management solution with all the benefits of a full
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transactional storage and the simplicity of a well known Java API.
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Java programmers who need fast, scalable, transactional data
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management for their projects can quickly adopt and deploy the
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DB Java Collections API with confidence.
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</p>
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<p>
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This framework was first known as
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<a class="ulink" href="http://greybird-db.sourceforge.net/" target="_top">Greybird DB</a>
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written by Mark Hayes. Mark collaborated with us to
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permanently incorporate his excellent work into our distribution
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and to support it as an ongoing part of Berkeley DB and Berkeley DB Java
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Edition. The repository of source code that remains at SourceForge at version 0.9.0 is
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considered the last version before incorporation and will remain
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intact but will not be updated to reflect changes made as part of
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Berkeley DB or Berkeley DB Java Edition.
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</p>
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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="features"></a>Features</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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<span>Berkeley DB has always provided a Java API which can be roughly
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described as a map and cursor interface, where the keys and values
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are represented as byte arrays. This API is a Java (JNI) interface
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to the C API and it closely modeled the Berkeley DB C API's
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interface.</span>
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The DB Java Collections API is a layer on top of
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<span>that
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thin JNI mapping of the C API to Berkeley DB.</span>
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It adds significant new functionality in several ways.
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</p>
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<div class="itemizedlist">
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<ul type="disc">
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<li>
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<p>
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An implementation of the Java Collections interfaces (Map,
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SortedMap, Set, SortedSet,
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<span>List</span>
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and Iterator) is provided.
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</p>
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</li>
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<li>
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<p>
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Transactions are supported using the conventional Java
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transaction-per-thread model, where the current transaction is
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implicitly associated with the current thread.
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</p>
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</li>
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<li>
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<p>
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Transaction runner utilities are provided that automatically
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perform transaction retry and exception handling.
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</p>
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</li>
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<li>
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<p>
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Keys and values are represented as Java objects rather than
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byte arrays. Bindings are used to map between Java objects and the
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stored byte arrays.
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</p>
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</li>
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<li>
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<p>
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The tuple data format is provided as the simplest data
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representation, and is useful for keys as well as simple compact
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values.
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</p>
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</li>
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<li>
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<p>
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The serial data format is provided for storing arbitrary Java
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objects without writing custom binding code. Java serialization is
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extended to store the class descriptions separately, making the
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data records much more compact than with standard Java
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serialization.
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</p>
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</li>
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<li>
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<p>
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Custom data formats and bindings can be easily added. XML data
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format and XML bindings could easily be created using this feature,
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for example.
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</p>
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</li>
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<li>
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<p>
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The DB Java Collections API insulates the application
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from minor differences in the use of the Berkeley DB Data Store,
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Concurrent Data Store, and Transactional Data Store products.
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This allows for development with one and deployment with another
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without significant changes to code.
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</p>
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</li>
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</ul>
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</div>
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<p>
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Note that the DB Java Collections API does not support caching
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of programming language objects nor does it keep track of their stored
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status. This is in contrast to "persistent object" approaches such
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as those defined by
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<a class="ulink" href="http://www.odmg.org/odmg.html" target="_top">ODMG</a>
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and JDO
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(<a class="ulink" href="http://www.jcp.org/en/jsr/detail?id=12" target="_top">JSR 12</a>).
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Such approaches have benefits but also require sophisticated object
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caching. For simplicity the DB Java Collections API treats data
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objects by value, not by reference, and does not perform object
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caching of any kind. Since the DB Java Collections API is a thin
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layer, its reliability and performance characteristics are roughly
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equivalent to those of Berkeley DB, and database tuning is
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accomplished in the same way as for any Berkeley DB database.
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</p>
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</div>
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</div>
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<div class="navfooter">
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<hr />
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|||
|
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<table width="100%" summary="Navigation footer">
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|||
|
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<tr>
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|||
|
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<td width="40%" align="left"><a accesskey="p" href="moreinfo.html">Prev</a> </td>
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|||
|
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<td width="20%" align="center"> </td>
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|||
|
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<td width="40%" align="right"> <a accesskey="n" href="developing.html">Next</a></td>
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</tr>
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|
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<tr>
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|||
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<td width="40%" align="left" valign="top">For More Information </td>
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|||
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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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|
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</td>
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<td width="40%" align="right" valign="top"> Developing a DB Collections Application</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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