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| <title>2. Custom Providers and Instruments</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_instrumentation.html" title="Chapter 16. Instrumentation"><link rel="prev" href="ref_guide_instrumentation.html" title="Chapter 16. Instrumentation"><link rel="next" href="appendices.html" title="Part 4. Appendices"></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">2. | |
| Custom Providers and Instruments | |
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| Instrumentation | |
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| Custom Providers and Instruments | |
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| <p> | |
| OpenJPA includes built-in support for a JMX Platform MBean provider, but a custom instrumentation | |
| providers can be created by implementing the | |
| <a class="ulink" href="../javadoc/org/apache/openjpa/lib/instrumentation/InstrumentationProvider.html" target="_top"> | |
| <code class="classname">InstrumentationProvider</code></a> interface or more simply by extending | |
| <a class="ulink" href="../javadoc/org/apache/openjpa/lib/instrumentation/AbstractInstrumentationProvider.html" target="_top"> | |
| <code class="classname">AbstractInstrumentationProvider</code></a>. To use the custom instrumentation provider, | |
| include the class in your classpath and specify the class name as the base value on the | |
| <a class="link" href="ref_guide_conf_openjpa.html#openjpa.Instrumentation" title="5.40. openjpa.Instrumentation"><code class="literal">openjpa.Instrumentation</code></a> configuration property. | |
| </p> | |
| <p> | |
| OpenJPA includes instruments for various caches, but you can also create your own instruments. To | |
| create a custom instrument you need to implement the | |
| <a class="ulink" href="../javadoc/org/apache/openjpa/lib/instrumentation/Instrument.html" target="_top"> | |
| <code class="classname">Instrument</code></a> interface or more simply extend | |
| <a class="ulink" href="../javadoc/org/apache/openjpa/lib/instrumentation/AbstractInstrument.html" target="_top"> | |
| <code class="classname">AbstractInstrument</code></a>. If you are building a Platform MBean JMX-based | |
| instrument this effort can be simplified by extending | |
| <a class="ulink" href="../javadoc/org/apache/openjpa/instrumentation/jmx/JMXInstrument.html" target="_top"> | |
| <code class="classname">JMXInstrument</code></a>. If you create your own custom | |
| provider, class name aliases can be registered within the provider to simplify configuration. For example, | |
| the instrument <code class="classname">com.my.app.MySQLInstrument</code> could be aliased as | |
| <code class="classname">MySQLInstrument</code> within custom provider | |
| <code class="classname">com.my.app.InstrumentationProvider</code>. | |
| </p> | |
| <p> | |
| OpenJPA provides the ability to plug in custom instruments and gives instruments direct access to the | |
| configuration, but it is up to the creator of the instrument to add the internal monitoring. This often | |
| requires modifying or extending base OpenJPA classes (such as the Broker) or using a byte-code weaving | |
| tool such as AspectJ to produce aspect-based instruments. | |
| </p> | |
| <p> | |
| Here is an example of how a custom instrumentation provider could be enabled with an instrument class | |
| aliased by the provider as <code class="classname">MySQLInstrument</code>. | |
| </p> | |
| <pre class="programlisting"> | |
| <!-- Enable custom provider and instrument --> | |
| <property name="openjpa.Instrumentation" value="com.my.app.InstrumentationProvider(Instrument='MySQLInstrument')"/> | |
| </pre> | |
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| Instrumentation | |
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