samples_guide.xml

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<chapter id="samples_guide">
    <title>
        OpenJPA Sample Code
    </title>
    <para>
The OpenJPA distribution comes with a number of examples that illustrate the
usage of various features.
    </para>
<!--
This is information on the sample application. It will be included
in the documentation (see doc/openjpa/samples-guide.xml). It will also
automatically be converted into a README.txt file in this directory
in the "release.openjpa.releasedocs" build target phase of the release.
-->
    <section id="samples_guide_interop">
        <title>
            JDO - JPA Persistence Interoperability
        </title>
        <para>
This sample demonstrates how to combine JDO and JPA in a single application. The
<filename>MachineMain.java</filename> program uses both <classname>
EntityManager</classname>s and <classname>PersistenceManager</classname>s in a
single transaction including persist, delete and query operations.
        </para>
        <para>
The sample includes both annotated persistent classes as well as JDOR metadata
information. The application can switch to either system simply by changing the
bootstrap mechanism. Depending on which configuration system you use, OpenJPA
will read the corresponding metadata format. You can override some or all of
this behavior using OpenJPA's configuration options, such as
<link linkend="openjpa.MetaDataFactory">openjpa.MetaDataFactory</link>.
        </para>
        <para>
To use this sample, you should ensure that either a <filename>jdo.properties
</filename> or <filename>persistence.xml</filename> are in the <filename>
META-INF</filename> directory in your <envar>CLASSPATH</envar>. The rest of the
files for this sample are located in the <filename>samples/mixed</filename>
directory of the OpenJPA installation. This tutorial requires JDK 5. To run this
tutorial:
        </para>
        <itemizedlist>
            <listitem>
                <para>
Ensure that your environment is set properly as described in the README and that
your current path is in the mixed sample directory.
                </para>
            </listitem>
            <listitem>
                <para>
You may want to edit <literal>ConnectionURL</literal> to point to an absolute
URL (e.g. <filename>C:/openjpa/mixed-sample-db</filename>) if using a
file-based database like <literal>HSQL</literal>.
                </para>
            </listitem>
            <listitem>
                <para>
Include the list of persistent classes in your configuration file. For JPA, you
will want to add the following lines to <filename>persistence.xml</filename>
before the <literal>&lt;property&gt;</literal> lines:
                </para>
<programlisting>
&lt;class&gt;samples.mixed.Machine&lt;/class&gt;
&lt;class&gt;samples.mixed.Crane&lt;/class&gt;
&lt;class&gt;samples.mixed.Bulldozer&lt;/class&gt;
&lt;class&gt;samples.mixed.Operator&lt;/class&gt;
</programlisting>
                <para>
If you are using JDO, point the metadata factory at the <filename>.jdo
</filename> resource containing your persistent classes:
                </para>
<programlisting>
openjpa.MetaDataFactory: Resources=samples/mixed/package.jdo
</programlisting>
            </listitem>
            <listitem>
                <para>
Compile the classes:
                </para>
                <para>
<userinput>javac *.java</userinput>
                </para>
            </listitem>
            <listitem>
                <para>
You should then proceed to pass in the configuration file you are using to the
enhancer:
                </para>
                <para>
<userinput>java org.apache.openjpa.enhance.PCEnhancer -p persistence.xml Machine.java Crane.java Bulldozer.java
Operator.java</userinput>
                </para>
            </listitem>
            <listitem>
                <para>
Similarly, you should pass in the same argument to <literal>org.apache.openjpa.jdbc.meta.MappingTool</literal>:
                </para>
                <para>
<userinput>java org.apache.openjpa.jdbc.meta.MappingTool -p persistence.xml -a buildSchema Machine.java
Crane.java Bulldozer.java Operator.java</userinput>
                </para>
                <para>
or
                </para>
                <para>
<userinput>java org.apache.openjpa.jdbc.meta.MappingTool -p jdo.properties -a buildSchema Machine.java Crane.java
Bulldozer.java Operator.java</userinput>
                </para>
            </listitem>
            <listitem>
                <para>
You can now run the sample application. The first argument is which operation
you want the program to run. The second argument tells the application which
bootstrap system to use:
                </para>
                <para>
<userinput>java samples.mixed.MachineMain &lt;create | delete&gt; &lt;jdo |
jpa&gt;</userinput>
                </para>
            </listitem>
        </itemizedlist>
    </section>
    <section id="samples_guide_jpadiv">
        <title>
            JPA
        </title>
<!--
This is information on the sample application. It will be included
in the documentation (see doc/openjpa/samples-guide.xml). It will also
automatically be converted into a README.txt file in this directory
in the "release.jdo.releasedocs" build target phase of the release.
-->
        <section id="samples_guide_model_humres_jpa">
            <title>
                Sample Human Resources Model
            </title>
            <para>
The files for this sample are located in the <filename>
samples/persistence/models/humres</filename> directory of the OpenJPA
installation. This sample demonstrates the mapping of an example "Human
Resources" schema. The following concepts are illustrated in this sample:
            </para>
            <itemizedlist>
                <listitem>
                    <para>
Value Mappings
                    </para>
                </listitem>
                <listitem>
                    <para>
One to One Mappings
                    </para>
                </listitem>
                <listitem>
                    <para>
One to Many Mappings (with and without inverses)
                    </para>
                </listitem>
            </itemizedlist>
        </section>
    </section>
</chapter>