/*
* 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 com.facebook.presto.operator.window;
import com.facebook.presto.metadata.Signature;
import com.facebook.presto.operator.Description;
import com.facebook.presto.spi.type.Type;
import com.google.common.base.Throwables;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.List;
import static com.google.common.base.Preconditions.checkNotNull;
public class ReflectionWindowFunctionSupplier<T extends WindowFunction>
extends AbstractWindowFunctionSupplier
{
private final Constructor<T> constructor;
public ReflectionWindowFunctionSupplier(String name, Type returnType, List<? extends Type> argumentTypes, Class<T> type)
{
this(new Signature(name, returnType, argumentTypes, false), type);
}
public ReflectionWindowFunctionSupplier(Signature signature, Class<T> type)
{
super(signature, getDescription(checkNotNull(type, "type is null")));
try {
if (signature.getArgumentTypes().isEmpty()) {
constructor = type.getConstructor();
}
else {
constructor = type.getConstructor(List.class);
}
}
catch (NoSuchMethodException e) {
throw Throwables.propagate(e);
}
}
@Override
protected T newWindowFunction(List<Integer> inputs)
{
try {
if (getSignature().getArgumentTypes().isEmpty()) {
return constructor.newInstance();
}
else {
return constructor.newInstance(inputs);
}
}
catch (InvocationTargetException e) {
throw Throwables.propagate(e.getCause());
}
catch (Exception e) {
throw Throwables.propagate(e);
}
}
private static String getDescription(AnnotatedElement annotatedElement)
{
Description description = annotatedElement.getAnnotation(Description.class);
return (description == null) ? null : description.value();
}
}