private static String getDescription(AnnotatedElement annotatedElement) {
Description description = annotatedElement.getAnnotation(Description.class);
return (description == null) ? null : description.value();
}
public static SqlScalarFunction parseDefinition(Class<?> clazz) {
ScalarFunction scalarAnnotation = clazz.getAnnotation(ScalarFunction.class);
ScalarOperator operatorAnnotation = clazz.getAnnotation(ScalarOperator.class);
Description descriptionAnnotation = clazz.getAnnotation(Description.class);
checkArgument(
scalarAnnotation != null || operatorAnnotation != null, "Missing parametric annotation");
checkArgument(
scalarAnnotation == null || operatorAnnotation == null,
"%s annotated as both an operator and a function",
clazz.getSimpleName());
if (scalarAnnotation != null) {
requireNonNull(
descriptionAnnotation,
format("%s missing @Description annotation", clazz.getSimpleName()));
}
String name;
String description = descriptionAnnotation == null ? "" : descriptionAnnotation.value();
boolean hidden;
boolean deterministic;
if (scalarAnnotation != null) {
name = scalarAnnotation.value();
hidden = scalarAnnotation.hidden();
deterministic = scalarAnnotation.deterministic();
} else {
name = mangleOperatorName(operatorAnnotation.value());
hidden = true;
deterministic = true;
}
ImmutableMap.Builder<Signature, Implementation> exactImplementations = ImmutableMap.builder();
ImmutableList.Builder<Implementation> specializedImplementations = ImmutableList.builder();
ImmutableList.Builder<Implementation> implementations = ImmutableList.builder();
Signature signature = null;
Map<Set<TypeParameter>, Constructor<?>> constructors = findConstructors(clazz);
for (Method method : findPublicMethodsWithAnnotation(clazz, SqlType.class)) {
Implementation implementation = new ImplementationParser(name, method, constructors).get();
if (implementation.getSignature().getTypeParameterRequirements().isEmpty()) {
exactImplementations.put(implementation.getSignature(), implementation);
continue;
}
if (signature == null) {
signature = implementation.getSignature();
} else {
checkArgument(
implementation.getSignature().equals(signature),
"Implementations with type parameters must all have matching signatures. %s does not match %s",
implementation.getSignature(),
signature);
}
if (implementation.hasSpecializedTypeParameters()) {
specializedImplementations.add(implementation);
} else {
implementations.add(implementation);
}
}
requireNonNull(signature, format("No implementations found for %s", name));
return new ReflectionParametricScalar(
signature,
description,
hidden,
exactImplementations.build(),
specializedImplementations.build(),
implementations.build(),
deterministic);
}