// Copyright 2012 Google Inc. All Rights Reserved.
package com.google.inject.throwingproviders;
import com.google.inject.Binder;
import com.google.inject.TypeLiteral;
import com.google.inject.internal.Annotations;
import com.google.inject.internal.Errors;
import com.google.inject.spi.Message;
import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Constructor;
/**
* Utilities for the throwing provider module.
*
* @author sameb@google.com (Sam Berlin)
*/
class CheckedProvideUtils {
private CheckedProvideUtils() {}
private static final String CONSTRUCTOR_RULES =
"Classes must have either one (and only one) constructor annotated with @ThrowingInject.";
@SuppressWarnings("unchecked") // safe because it's a constructor of the typeLiteral
static <T> Constructor<? extends T> findThrowingConstructor(
TypeLiteral<? extends T> typeLiteral, Binder binder) {
Class<?> rawType = typeLiteral.getRawType();
Errors errors = new Errors(rawType);
Constructor<?> cxtor = null;
for (Constructor<?> constructor : rawType.getDeclaredConstructors()) {
if (constructor.isAnnotationPresent(ThrowingInject.class)) {
if (cxtor != null) {
errors.addMessage("%s has more than one constructor annotated with @ThrowingInject. "
+ CONSTRUCTOR_RULES, rawType);
}
cxtor = constructor;
Annotation misplacedBindingAnnotation = Annotations.findBindingAnnotation(
errors, cxtor, ((AnnotatedElement) cxtor).getAnnotations());
if (misplacedBindingAnnotation != null) {
errors.misplacedBindingAnnotation(cxtor, misplacedBindingAnnotation);
}
}
}
if (cxtor == null) {
errors.addMessage(
"Could not find a suitable constructor in %s. " + CONSTRUCTOR_RULES, rawType);
}
for (Message msg : errors.getMessages()) {
binder.addError(msg);
}
return (Constructor<? extends T>) cxtor;
}
/** Adds errors to the binder if the exceptions aren't valid. */
static void validateExceptions(Binder binder,
Iterable<TypeLiteral<?>> actualExceptionTypes,
Iterable<Class<? extends Throwable>> expectedExceptionTypes,
Class<? extends CheckedProvider> checkedProvider) {
// Validate the exceptions in the method match the exceptions
// in the CheckedProvider.
for (TypeLiteral<?> exType : actualExceptionTypes) {
Class<?> exActual = exType.getRawType();
// Ignore runtime exceptions & errors.
if (RuntimeException.class.isAssignableFrom(exActual)
|| Error.class.isAssignableFrom(exActual)) {
continue;
}
boolean notAssignable = true;
for (Class<? extends Throwable> exExpected : expectedExceptionTypes) {
if (exExpected.isAssignableFrom(exActual)) {
notAssignable = false;
break;
}
}
if (notAssignable) {
binder.addError(
"%s is not compatible with the exceptions (%s) declared in "
+ "the CheckedProvider interface (%s)",
exActual, expectedExceptionTypes, checkedProvider);
}
}
}
}