/**
* Locate a constructor on the type. There are three kinds of match that might occur:
*
* <ol>
* <li>An exact match where the types of the arguments match the types of the constructor
* <li>An in-exact match where the types we are looking for are subtypes of those defined on the
* constructor
* <li>A match where we are able to convert the arguments into those expected by the
* constructor, according to the registered type converter.
* </ol>
*/
@Override
public ConstructorExecutor resolve(
EvaluationContext context, String typename, List<TypeDescriptor> argumentTypes)
throws AccessException {
try {
TypeConverter typeConverter = context.getTypeConverter();
Class<?> type = context.getTypeLocator().findType(typename);
Constructor<?>[] ctors = type.getConstructors();
Arrays.sort(
ctors,
new Comparator<Constructor<?>>() {
@Override
public int compare(Constructor<?> c1, Constructor<?> c2) {
int c1pl = c1.getParameterTypes().length;
int c2pl = c2.getParameterTypes().length;
return (new Integer(c1pl)).compareTo(c2pl);
}
});
Constructor<?> closeMatch = null;
for (Constructor<?> ctor : ctors) {
Class<?>[] paramTypes = ctor.getParameterTypes();
List<TypeDescriptor> paramDescriptors = new ArrayList<TypeDescriptor>(paramTypes.length);
for (int i = 0; i < paramTypes.length; i++) {
paramDescriptors.add(new TypeDescriptor(new MethodParameter(ctor, i)));
}
ReflectionHelper.ArgumentsMatchInfo matchInfo = null;
if (ctor.isVarArgs() && argumentTypes.size() >= paramTypes.length - 1) {
// *sigh* complicated
// Basically.. we have to have all parameters match up until the varargs one, then the
// rest of what is
// being provided should be
// the same type whilst the final argument to the method must be an array of that (oh, how
// easy...not) -
// or the final parameter
// we are supplied does match exactly (it is an array already).
matchInfo =
ReflectionHelper.compareArgumentsVarargs(
paramDescriptors, argumentTypes, typeConverter);
} else if (paramTypes.length == argumentTypes.size()) {
// worth a closer look
matchInfo =
ReflectionHelper.compareArguments(paramDescriptors, argumentTypes, typeConverter);
}
if (matchInfo != null) {
if (matchInfo.isExactMatch()) {
return new ReflectiveConstructorExecutor(ctor);
} else if (matchInfo.isCloseMatch() || matchInfo.isMatchRequiringConversion()) {
closeMatch = ctor;
}
}
}
return (closeMatch != null ? new ReflectiveConstructorExecutor(closeMatch) : null);
} catch (EvaluationException ex) {
throw new AccessException("Failed to resolve constructor", ex);
}
}
