/*
* 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.internal;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.util.Collections;
import java.util.Set;
import java.util.function.Supplier;
import java.util.stream.Collector;
import java.util.stream.Collectors;
import org.jdbi.v3.core.internal.exceptions.Unchecked;
@SuppressWarnings("rawtypes")
public final class CollectionCollectors {
private static final Supplier<Collector> SET_COLLECTOR = setFactory();
private CollectionCollectors() {}
private static Supplier<Collector> setFactory() {
try {
MethodHandle mh = MethodHandles.publicLookup()
.findStatic(Collectors.class, "toUnmodifiableSet", MethodType.methodType(Collector.class));
return Unchecked.supplier(() -> (Collector) mh.invokeExact());
} catch (final ReflectiveOperationException ignore) {
// ignored for java 8+9 compat
}
return () -> Collectors.collectingAndThen(
Collectors.toSet(),
Collections::unmodifiableSet);
}
@SuppressWarnings("unchecked")
public static <T> Collector<T, ?, Set<T>> toUnmodifiableSet() {
return SET_COLLECTOR.get();
}
}