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Feature Request
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Resolution: Done
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L3 - Default
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None
Currently users have to write code in order to enable java 8 date/time types in Spin
The idea behind this feature request would be to provide spring boot auto configuration that did this - triggered by a maven dependency.
The exact configuration could then be done be done as (spring boot) yaml parameters.
For reference, this is what a user would do:
1 - add the maven dependency
<dependency> <groupId>org.camunda.spin</groupId> <artifactId>camunda-spin-dataformat-json-jackson</artifactId> <version>1.6.5</version> </dependency>
2 - register javatimemodule through a DataFormatConfigurator
@Component public class CamundaJacksonFormatConfigurator implements DataFormatConfigurator<JacksonJsonDataFormat> { @Override public Class<JacksonJsonDataFormat> getDataFormatClass() { return JacksonJsonDataFormat.class; } @Override public void configure(JacksonJsonDataFormat dataFormat) { final ObjectMapper mapper = dataFormat.getObjectMapper(); final JavaTimeModule javaTimeModule = new JavaTimeModule(); mapper.registerModule(javaTimeModule); } }
3 - create file entry in META-INF/services/org.camunda.spin.spi.DataFormatConfigurator in order to register component (CamundaJacksonFormatConfigurator )
This is the controller panel for Smart Panels app
[CAM-9972] Auto Configuration for Java8/JSR-310 Date-Time types in Spring Boot
Design decisions:
- Add the camunda-spin-dataformat-json-jackson dependency as optional. This way, the user will need to explicitly declare it for the dependency to be added on the classpath;
- Create a CamundaJacksonFormatConfigurator bean on the condition that the JacksonJsonDataFormat class is present on the classpath. The class is available from the above-mentioned dependency;
- Register the Jackson Java8 modules in the new CamundaJacksonFormatConfigurator class.
- We don't need to use SPI since the configuration will be registered through the CamundaBpmAutoConfiguration class in the spring.factories file. See the spring docs [here](https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-developing-auto-configuration.html#boot-features-class-conditions) for why a separate class with a Configuration annotation is needed.
- Spring Boot already provides Jackson configuration properties. See [here](https://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#howto-customize-the-jackson-objectmapper) for more details.
Design decisions:
Spin uses the Java SPI ServiceLoader class to load additional DataFormat configurations (through the org.camunda.spin.spi.DataFormatConfigurator interface). The loading is performed through the DataFormats class, in a singleton instance, which makes extending the DataFormats class complicated. In addition, the ServiceLoader class is incompatible with the META-INF/spring.factories file, and we can't use "Spring" syntax to ensure auto-configuration.
To resolve the problem, the following things were performed:
- Modify the Spin#DataFormats class to accept a list of DataFormatConfigurator instances when loading DataFormats;
- Extend the SpinProcessEnginePlugin to pass the above mentioned list;
- Provide separate DataFormatConfigurator beans for the Jackson Java 8 modules, in the Spring Boot auto-configuration classes. These are then passed as arguments when the DataFormats are loaded in the SpringBootSpinProcessEnginePlugin.
Implemented the review hints.
- The getAvailableDataFormatsMap getter method was added for a previous solution that wasn't used. Since it remained unused, I removed it now;
- The new applyConfigurators method is protected, and only used internally by the methods of the DataFormats class. We shouldn't cover it in tests explicitly;
- I added tests for the new registerDataFormats and loadDataFormats methods.
- The registerDataFormats method is only used by the new loadDataFormats method. However, since the other variant is Public API, I decided to make it public as well.
Consider also using the other Java8 modules for Jackson out of the box, see https://github.com/FasterXML/jackson-modules-java8