Features for Cross Cutting Concerns

Features are additions to the expandersExpanderA unit of generation that combines a data tree instance (functional M1 model) with a template to generate an artifact. which aim to add pieces of code to multiple expandersExpanderA unit of generation that combines a data tree instance (functional M1 model) with a template to generate an artifact.. A feature can then be enabled with some option or another condition to add logic to multiple artifactsArtifactA build or deployment result, such as a Docker container image or Java archive, produced by a software project. at once.

That way, crosscutting concerns can be extracted from the expandersExpanderA unit of generation that combines a data tree instance (functional M1 model) with a template to generate an artifact. to provide further decoupling.

Here is an example to paint a clearer image. Let's say we want to expose a new method of the dataElement-bean:

public <F> SearchResult<CityDetails> findAllDetails(ParameterContext<F> parameter) {
  ...
}

This method also needs to be added to the Remote interface:

<F> SearchResult<CityDetails> findAllDetails(ParameterContext<F> parameter);

And some more to the Local, Proxy and Agent.

Feature vs. Expander Feature

First, a Feature is defined. Then, for each ExpanderExpanderA unit of generation that combines a data tree instance (functional M1 model) with a template to generate an artifact. that will be modified by the Feature, an ExpanderFeature should be created.

Feature Files

• a {Feature}.xml file containing a condition, which is similar to the isApplicable of the ExpanderExpanderA unit of generation that combines a data tree instance (functional M1 model) with a template to generate an artifact. and a type, which can be custom (each insertion is different for each artifactArtifactA build or deployment result, such as a Docker container image or Java archive, produced by a software project.) or uniform (each artifactArtifactA build or deployment result, such as a Docker container image or Java archive, produced by a software project. has the same insertion)
• a {Feature}.md file which contains a description of the feature
• a {Feature}Test.java file which contains the units tests

Expander Feature Files

The ExpanderFeature provides the mapping and templates for the inserted code.

• a {Feature}.{Expander}Mapping.xml file to provide additional mappings for the insertion
• a {Feature}.{Expander}.stg file to provide a template
• a {Feature}{Expander}Test.java file for the units tests
• a {Feature}{Expander}Test.stg file to provide the test templates

The content of the {Feature}.{Expander}.stg file should contain hooks with the insertions:

base() ::= <<
@hook:methods:start
public \<F\> SearchResult\<<dataelement>Details\> findAllDetails(ParameterContext\<F\> parameter) {
  ...
}
@hook:methods:end
>>

The @hook:methods refers to an @anchor:methods feature anchorAnchorA marker within generated source code reserved for adding custom logic during re-expansion. in the original expanderExpanderA unit of generation that combines a data tree instance (functional M1 model) with a template to generate an artifact. template. You can add these feature anchorsAnchorA marker within generated source code reserved for adding custom logic during re-expansion. to your own ExpandersExpanderA unit of generation that combines a data tree instance (functional M1 model) with a template to generate an artifact. to allow for them to be extended.

When expanding, the insertion will be injected into the artifactArtifactA build or deployment result, such as a Docker container image or Java archive, produced by a software project. at the place of the feature anchorAnchorA marker within generated source code reserved for adding custom logic during re-expansion. as follows:

// @anchor:methods:start
public <F> SearchResult<CityDetails> findAllDetails(ParameterContext<F> parameter) {
  ...
}
// @anchor:methods:end

A more elaborate guide on how to set up features using the intelliJ plugin can be found in the developer hub: Features