Template / Automation Engine

Background

The template engine is based on the transformation's renderer approach and uses different renderers and condition to perform the different tasks. For this, the default available tasks are configured in the template-config.xml spring configuration file.

How to use the template engine

Basically the template engine uses the GeneratorTemplateRenderer class to do the rendering. For this, by default the bean generatorTemplateRenderer can be used. This class can be executed using a GeneratorTemplate which has to be instantiated using the GeneratorTemplateFactory and a TemplateResource. To add custom data to the process the template can be enhanced by a Properties element. Thus, the base process that is required to execute a task are the following:

GeneratorTemplateFactory generatorTemplateFactory = ...;
GeneratorTemplateRenderer<GeneratorTemplate, Void> generatorTemplateRenderer = ...;
TemplateResource templateResource = new TemplateResource("pathToTemplateFile.yaml");

Properties myProperties = new Properties();
// add custom properties

GeneratorTemplate template = generatorTemplateFactory.loadGeneratorTemplate(templateResource);
generatorTemplateRenderer.renderElement(myProperties, null); // the second value is ignore for this type

With that base definition a given template is rendered. Of course this requires to configure a template resource yaml file. An example file is provided here (this of course requires configuration of the properties, etc. and should only give an idea of how the syntax looks and how the different task types are used):

templateName: generateDocumentation
templateTasks:
  - name: createGraphWizDir
    type: createDirectory
    properties:
      path: ${project}/src/site/resources/js/fhir2bpmn

  - name: createMarkdownDir
    type: createDirectory
    properties:
      path: ${project}/src/site/markdown/fhir2bpmn/

  - name: createMarkdown
    type: instantiateTemplate
    properties:
      template: classpath:/template/fhir2bpmndoc.ftl
      dest: ${project}/src/site/markdown/fhir2bpmn/${filename}.md

  - name: unzipAutoLayout
    type: unzip
    properties:
      src: classpath:/bpmn-auto-layout.zip
      dest: ${project}/target/

  - name: createBpmn
    type: instantiateTemplate
    properties:
      template: classpath:/template/bpmn.ftl
      dest: ${project}/target/bpmn-auto-layout/test/fixtures/transform.bpmn

  - name: processNpm
    type: shell
    properties:
      commands:
        - cmd /c npm install
        - cmd /c npm run all
      workdir: ${project}/target/bpmn-auto-layout/
      timeout: 60000 # ms --> 1 min (for each command)

  - name: deleteBpmnJs
    type: deleteFile
    properties:
      path: ${project}/src/site/resources/js/fhir2bpmn/${filename}.js

  - name: copyBpmnJs
    type: copyFile
    properties:
      src: ${project}/target/bpmn-auto-layout/test/generated/transform.bpmn
      dest: ${project}/src/site/resources/js/fhir2bpmn/${filename}.js

Each template task inside the template needs to have an unique name over the file. The type of the template task specifies what the task is doing, therefore different types are available which are described in the section blow. The properties which are required differ from type to type. For each property placeholders can be defined. These are using the ${placeholder_name} syntax. These placeholders are replaced with the Properties defined in the java code. Meaning if we define a property: myProperties.setProperty("placeholder_name", "myCustomValue"); that each time ${placeholder_name} is used inside the yaml file it gets replaced by myCustomValue.

Template tasks and configuration

The following Tasks are currently supported:

• Delete File
• Copy Directory
• Create Directory
• Copy File
• GraphViz
• Template
• Unzip
• Shell

As we already defined, each task needs a name and type as well as a list of properties, that is described in this section.