code: public final void execute() throws MojoExecutionException,
  			MojoFailureException {
  
  		// If skip flag set then omit image generation
  		if (isSkip()) {
  			getLog().info("Skipping creation of image files");
  		} else {
  
  			// Run the dot command only if dot files have been changed
  			Set<String> changedDotFiles = getChangedDotFiles();
  			if (changedDotFiles != null && !changedDotFiles.isEmpty()) {
  				if (!executeDot(changedDotFiles)) {
  					throw new MojoExecutionException("Executing '" + command
  							+ "' command failed");
  				}
  			}
  		}
  	}
docs: Strategy implementation of running the command line tool <code>dot</code>
  :
  <ol>
  <li>check the <code>skip</code> flag
  <li>get a list of modified dot files from the StatusFile
  <li>run the dot command
  </ol>