supplementing-from-source-code.md

Supplementing the model from source code

Most of the component finder strategies included in Structurizr for Java find components using reflection against the compiled bytecode. Some useful information exists in the source code though; including:

• The type-level doc comment (/** ... */, typically extracted using the javadoc tool). This can be used to populate the description property of components.
• The number of lines of source code. This can be a used to calculate the "size" of a component.

A pre-built SourceCodeComponentFinderStrategy is provided to do this, which uses the standard javadoc tool. You will need to include JAVA_HOME/lib/tools.jar on your classpath.

Example

Here's an example of how to use the SourceCodeComponentFinderStrategy, taken from the Spring PetClinic example.

File sourceRoot = new File("/some/path");

ComponentFinder componentFinder = new ComponentFinder(
    webApplication, "org.springframework.samples.petclinic",
    new SpringComponentFinderStrategy(
            new ReferencedTypesSupportingTypesStrategy(false)
    ),
    new SourceCodeComponentFinderStrategy(new File(sourceRoot, "/src/main/java/"), 150));

componentFinder.findComponents();

For every CodeElement that belongs to every Component in the Container passed to the ComponentFinder, the SourceCodeComponentFinderStrategy will:

• Set the description property, based on the type-level doc comment. The doc comment will be truncated if necessary (e.g. to 150 characters in the example above).
• Set the size property to be the number of lines of the file that the type was found in.

Additionally, the description property of the Component will be set to be that of the primary CodeElement, if a description has not been set on the Component already.