title: Are Filer's originating elements useful?
body: <p>I'm working on a Java program (<a href="https://github.com/square/dagger" rel="noreferrer">Dagger</a>) that uses the Java annotation processing API to generate code. When our program encounters an annotation in <code>Foo.java</code>, it generates <code>Foo$$InjectAdapter.java</code>. We use the <a href="http://docs.oracle.com/javase/6/docs/api/javax/annotation/processing/Filer.html" rel="noreferrer"><code>Filer</code></a> API to attach the originating <code>Element</code> that triggered the generated code.</p>
  
  <p>The Filer docs say that this is intended to aid incremental builds:</p>
  
  <blockquote>
    <p><em>"This information may be used in an incremental environment to determine the need to rerun processors or remove generated files. Non-incremental environments may ignore the originating element information."</em></p>
  </blockquote>
  
  <p>Does anyone know of an incremental environment that use this information? Does <code>javac</code> or the Eclipse compiler use this information?</p>