Demystifying Butterknife

ButterKnifeProcessor-parseBindView.java

private void parseBindView(Element element, Map<TypeElement, BindingSet.Builder> builderMap,
    Set<TypeElement> erasedTargetNames) {
  TypeElement enclosingElement = (TypeElement) element.getEnclosingElement();
  ...
  // Assemble information on the field.
  int id = element.getAnnotation(BindView.class).value();

  BindingSet.Builder builder = builderMap.get(enclosingElement);
  QualifiedId qualifiedId = elementToQualifiedId(element, id);
  if (builder != null) {
    String existingBindingName = builder.findExistingBindingName(getId(qualifiedId));      
    ...
  } else {
    builder = getOrCreateBindingBuilder(builderMap, enclosingElement);
  }

  String name = simpleName.toString();
  TypeName type = TypeName.get(elementType);
  boolean required = isFieldRequired(element);

  builder.addField(getId(qualifiedId), new FieldViewBinding(name, type, required));

  // Add the type-erased version to the valid binding targets set.
  erasedTargetNames.add(enclosingElement);
}