| <html><head> |
| <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> |
| <title>Chapter 5. Persistent Classes</title><base href="display"><link rel="stylesheet" type="text/css" href="css/docbook.css"><meta name="generator" content="DocBook XSL Stylesheets V1.79.1"><link rel="home" href="manual.html" title="Apache OpenJPA 2.4 User's Guide"><link rel="up" href="ref_guide.html" title="Part 3. Reference Guide"><link rel="prev" href="ref_guide_schema_xml.html" title="14. XML Schema Format"><link rel="next" href="ref_guide_pc_enhance.html" title="2. Enhancement"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 5. |
| Persistent Classes |
| </th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ref_guide_schema_xml.html">Prev</a> </td><th width="60%" align="center">Part 3. Reference Guide</th><td width="20%" align="right"> <a accesskey="n" href="ref_guide_pc_enhance.html">Next</a></td></tr></table><hr></div><div class="chapter" id="ref_guide_pc"><div class="titlepage"><div><div><h2 class="title">Chapter 5. |
| Persistent Classes |
| </h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl class="toc"><dt><span class="section"><a href="ref_guide_pc.html#ref_guide_pc_pcclasses">1. |
| Persistent Class List |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_enhance.html">2. |
| Enhancement |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_pc_enhance.html#ref_guide_pc_enhance_build">2.1. |
| Enhancing at Build Time |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_enhance.html#ref_guide_pc_enhance_runtime_container">2.2. |
| Enhancing JPA Entities on Deployment |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_enhance.html#ref_guide_pc_enhance_runtime">2.3. |
| Enhancing at Runtime |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_enhance.html#ref_guide_pc_enhance_dynamic">2.4. |
| Enhancing Dynamically at Runtime |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_enhance.html#ref_guide_pc_enhance_unenhanced_types">2.5. |
| Omitting the OpenJPA enhancer |
| </a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_pc_interfaces.html">3. Managed Interfaces</a></span></dt><dt><span class="section"><a href="ref_guide_pc_oid.html">4. |
| Object Identity |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_pc_oid.html#ref_guide_pc_oid_datastore">4.1. |
| Datastore Identity |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_oid.html#ref_guide_pc_oid_entitypk">4.2. |
| Entities as Identity Fields |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_oid.html#ref_guide_pc_oid_application">4.3. |
| Application Identity Tool |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_oid.html#ref_guide_pc_oid_pkgen_autoinc">4.4. |
| Autoassign / Identity Strategy Caveats |
| </a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_inverses.html">5. |
| Managed Inverses |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_scos.html">6. |
| Persistent Fields |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_pc_scos.html#ref_guide_pc_scos_restore">6.1. |
| Restoring State |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_scos.html#ref_guide_pc_scos_order">6.2. |
| Typing and Ordering |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_scos.html#ref_guide_pc_calendar_timezone">6.3. |
| Calendar Fields and TimeZones |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_scos.html#ref_guide_pc_scos_proxy">6.4. |
| Proxies |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_pc_scos.html#ref_guide_pc_scos_proxy_smart">6.4.1. |
| Smart Proxies |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_scos.html#ref_guide_pc_scos_proxy_lrs">6.4.2. |
| Large Result Set Proxies |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_scos.html#ref_guide_pc_scos_proxy_custom">6.4.3. |
| Custom Proxies |
| </a></span></dt><dt><span class="section"><a href="ref_guide_pc_scos.html#ref_guide_pc_scos_proxy_serial">6.4.4. |
| Serialization |
| </a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_pc_scos.html#ref_guide_pc_extern">6.5. |
| Externalization |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_pc_scos.html#ref_guide_pc_extern_values">6.5.1. |
| External Values |
| </a></span></dt></dl></dd></dl></dd><dt><span class="section"><a href="ref_guide_fetch.html">7. |
| Fetch Groups |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_fetch.html#ref_guide_fetch_custom">7.1. |
| Custom Fetch Groups |
| </a></span></dt><dt><span class="section"><a href="ref_guide_fetch.html#ref_guide_fetch_conf">7.2. |
| Custom Fetch Group Configuration |
| </a></span></dt><dt><span class="section"><a href="ref_guide_fetch.html#ref_guide_fetch_single_field">7.3. |
| Per-field Fetch Configuration |
| </a></span></dt><dt><span class="section"><a href="ref_guide_fetch.html#ref_guide_fetch_impl">7.4. |
| Implementation Notes |
| </a></span></dt></dl></dd><dt><span class="section"><a href="ref_guide_perfpack_eager.html">8. |
| Eager Fetching |
| </a></span></dt><dd><dl><dt><span class="section"><a href="ref_guide_perfpack_eager.html#ref_guide_perfpack_eager_conf">8.1. |
| Configuring Eager Fetching |
| </a></span></dt><dt><span class="section"><a href="ref_guide_perfpack_eager.html#ref_guide_perfpack_eager_consider">8.2. |
| Eager Fetching Considerations and Limitations |
| </a></span></dt></dl></dd></dl></div> |
| |
| <a class="indexterm" name="d5e12108"></a> |
| <p> |
| Persistent class basics are covered in <a class="xref" href="jpa_overview_pc.html" title="Chapter 4. Entity">Chapter 4, <i> |
| Entity |
| </i></a> |
| of the JPA Overview. This chapter details the persistent class features OpenJPA |
| offers beyond the core JPA specification. |
| </p> |
| <div class="section" id="ref_guide_pc_pcclasses"><div class="titlepage"><div><div><h2 class="title" style="clear: both">1. |
| Persistent Class List |
| </h2></div></div></div> |
| |
| <a class="indexterm" name="d5e12114"></a> |
| <a class="indexterm" name="d5e12117"></a> |
| <p> |
| Unlike many ORM products, OpenJPA does not need to know about all of your |
| persistent classes at startup. OpenJPA discovers new persistent classes |
| automatically as they are loaded into the JVM; in fact you can introduce new |
| persistent classes into running applications under OpenJPA. However, there are |
| certain situations in which providing OpenJPA with a persistent class list is |
| helpful: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| <p> |
| OpenJPA must be able to match entity names in JPQL queries to persistent |
| classes. OpenJPA automatically knows the entity names of any persistent classes |
| already loaded into the JVM. To match entity names to classes that have not been |
| loaded, however, you must supply a persistent class list. |
| </p> |
| </li><li class="listitem"> |
| <p> |
| When OpenJPA manipulates classes in a persistent inheritance hierarchy, OpenJPA |
| must be aware of all the classes in the hierarchy. If some of the classes have |
| not been loaded into the JVM yet, OpenJPA may not know about them, and queries |
| may return incorrect results. |
| </p> |
| </li><li class="listitem"> |
| <p> |
| If you configure OpenJPA to create the needed database schema on startup (see |
| <a class="xref" href="ref_guide_mapping.html#ref_guide_mapping_synch" title="1.3. Runtime Forward Mapping">Section 1.3, “ |
| Runtime Forward Mapping |
| ”</a>), OpenJPA must know all of your |
| persistent classes up-front. |
| </p> |
| </li></ul></div> |
| <p> |
| When any of these conditions are a factor in your JPA application, use the |
| <code class="literal">class</code>, <code class="literal">mapping-file</code>, and <code class="literal"> |
| jar-file</code> elements of JPA's standard XML format to list your persistent |
| classes. See <a class="xref" href="jpa_overview_persistence.html#jpa_overview_persistence_xml" title="1. persistence.xml">Section 1, “ |
| persistence.xml |
| ”</a> for details. |
| </p> |
| <p> |
| Alternately, you can tell OpenJPA to search through your classpath for |
| persistent types. This is described in more detail in |
| <a class="xref" href="ref_guide_meta.html#ref_guide_meta_factory" title="1. Metadata Factory">Section 1, “ |
| Metadata Factory |
| ”</a>. |
| </p> |
| <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3> |
| <p> |
| Listing persistent classes (or their metadata or jar files) is an all-or-nothing |
| endeavor. If your persistent class list is non-empty, OpenJPA will assume that |
| any unlisted class is not persistent. |
| </p> |
| </div> |
| </div> |
| |
| |
| |
| |
| |
| |
| |
| </div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ref_guide_schema_xml.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ref_guide.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ref_guide_pc_enhance.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">14. |
| XML Schema Format |
| </td><td width="20%" align="center"><a accesskey="h" href="manual.html">Home</a></td><td width="40%" align="right" valign="top"> 2. |
| Enhancement |
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