Template / Automation Engine

The template/automation engine is a concept that allows executing different tasks by just providing a simple yaml-based configuration file.


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

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

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

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

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

  - name: processNpm
    type: shell
        - 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
      path: ${project}/src/site/resources/js/fhir2bpmn/${filename}.js

  - name: copyBpmnJs
    type: copyFile
      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.

Delete File

Property Description
path The path to the file that should be deleted. (Required)
errorNoExist If an error should be thrown if the file does not exist, else the error is ignored but logged. (Optional. Default: true)

Copy Directory

Property Description
src The path of the source directory (Required.)
dest The path of the target directory (Required.)

Create Directory

Property Description
path The path of the directory that should be created (Required.)

Copy File

Property Description
src The path of the source file (Required.)
dest The path of the target file (Required.)


Property Description
src The path of the source graphwiz file (Required.)
dest The path of the target png image (Required.)


Property Description
template The path to the template file that should be used for the template engine. (Required.) Per Default the FreeMarker template engine is used. If there is no other bean configured. Thus you have to make sure, that the template file is a valid freemarker template.
dest The path of the resulting file (Required.)
append Boolean Flag if the content should be appended to the file or overwriting the file, if it already exists. (Optional. Default: false)


Property Description
src The path of the zip file (Required.)
dest The path of the destination folder (Required.)


Property Description
command The command that should be executed (Required. Not allowed when commands is used)
commands A list of commands that should be executed (Required. Not allowed when command is used)
environment A list of environment strings. This value is used for the envp parameter of the Runtime.exec command. (Optional. Default: not set)
workdir The workdir where the command should be executed. This value is used for the dir parameter of the Runtime.exec command. (Optional. Default: not set)
timeout A timeout in ms, after which the method returns if the process has not yet finished. (Optional. Default: no timeout)