/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jdbi.v3.core.mapper.reflect;
import java.lang.reflect.Constructor;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;
/**
* Utilities for {@link JdbiConstructor} annotation.
*/
public class JdbiConstructors {
/**
* Find an invokable constructor. Prefer an {@link JdbiConstructor} annotated
* one if present. Throws if multiple or zero candidates are found.
* @param type
* @return
*/
public static <T> Constructor<T> findConstructorFor(Class<T> type) {
@SuppressWarnings("unchecked")
final Constructor<T>[] constructors = (Constructor<T>[]) type.getDeclaredConstructors();
List<Constructor<T>> annotatedConstructors = Stream.of(constructors)
.filter(c -> c.isAnnotationPresent(JdbiConstructor.class))
.collect(Collectors.toList());
if (annotatedConstructors.size() > 1) {
throw new IllegalArgumentException(type + " must have at most one constructor annotated @JdbiConstructor");
} else if (annotatedConstructors.size() == 1) {
return annotatedConstructors.get(0);
}
if (constructors.length != 1) {
throw new IllegalArgumentException(type + " must have exactly one constructor, or specify it with @JdbiConstructor");
}
return constructors[0];
}
}