Permalink
Fetching contributors…
Cannot retrieve contributors at this time
58 lines (52 sloc) 2.27 KB

Configure SPI Providers

The specifics of each configuration setting is discussed elsewhere in context with that setting. However, it is useful to understand the format used to declare settings on SPI providers.

{project_name} is a highly modular system that allows great flexibility. There are more than 50 service provider interfaces (SPIs), and you are allowed to swap out implementations of each SPI. An implementation of an SPI is known as a provider.

All elements in an SPI declaration are optional, but a full SPI declaration looks like this:

<spi name="myspi">
    <default-provider>myprovider</default-provider>
    <provider name="myprovider" enabled="true">
        <properties>
            <property name="foo" value="bar"/>
        </properties>
    </provider>
    <provider name="mysecondprovider" enabled="true">
        <properties>
            <property name="foo" value="foo"/>
        </properties>
    </provider>
</spi>

Here we have two providers defined for the SPI myspi. The default-provider is listed as myprovider. However it is up to the SPI to decide how it will treat this setting. Some SPIs allow more than one provider and some do not. So default-provider can help the SPI to choose.

Also notice that each provider defines its own set of configuration properties. The fact that both providers above have a property called foo is just a coincidence.

The type of each property value is interpreted by the provider. However, there is one exception. Consider the jpa provider for the eventsStore SPI:

<spi name="eventsStore">
    <provider name="jpa" enabled="true">
        <properties>
            <property name="exclude-events" value="[&quot;EVENT1&quot;,
                                                    &quot;EVENT2&quot;]"/>
        </properties>
    </provider>
</spi>

We see that the value begins and ends with square brackets. That means that the value will be passed to the provider as a list. In this example, the system will pass the provider a list with two element values EVENT1 and EVENT2. To add more values to the list, just separate each list element with a comma. Unfortunately, you do need to escape the quotes surrounding each list element with &quot;.