Question

Can anyone provide me with a code snippet of a simple java annotation processor that just prints “foo” when its process method is called. I’ve been working at this for 2 days and I haven’t been able to get that far

here is my code:

public class ComplexityProcessor extends AbstractProcessor {

    public ComplexityProcessor() {
        super();
    }

    @Override
    public boolean process(Set annotations,
                           RoundEnvironment roundEnv) {
        String message = "annotation found in ";
        processingEnv.getMessager().printMessage(javax.tools.Diagnostic.Kind.NOTE, message);

        try {
            JavaFileObject jfo = processingEnv.getFiler().createSourceFile("Foo");
            BufferedWriter bw = new BufferedWriter(jfo.openWriter());
            bw.append("Bar!!!");
            bw.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        for (Element elem : roundEnv.getElementsAnnotatedWith(Complexity.class)) {
            Complexity complexity = elem.getAnnotation(Complexity.class);
            message = "annotation found in " + elem.getSimpleName()
                           + " with complexity " + complexity.value();
            processingEnv.getMessager().printMessage(javax.tools.Diagnostic.Kind.NOTE, message);
            try {
                JavaFileObject jfo = processingEnv.getFiler().createSourceFile("Foo");
                BufferedWriter bw = new BufferedWriter(jfo.openWriter());
                bw.append("Bar!!!");
                bw.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
        return true; // no further processing of this annotation type
    }

Answer 1

I have discovered the answer

So what you need for the future:

1. A jar with the annotation processor and any mentioned annotations, so that you won’t have a problem with the classpath
2. A text file in META-INF/services/processor file with the name of the processor class. This also goes in the jar above where my processor is
3. Compile using the javac -processor argument. This was what I was looking for that was not mentioned on the 3 or 4 tutorials I was initially using