/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.vertexium.security;
import java.lang.reflect.Constructor;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
* General reflection utils
*/
class ReflectionUtils {
private static final Class<?>[] EMPTY_ARRAY = new Class[]{};
/**
* Cache of constructors for each class. Pins the classes so they
* can't be garbage collected until ReflectionUtils can be collected.
*/
private static final Map<Class<?>, Constructor<?>> CONSTRUCTOR_CACHE =
new ConcurrentHashMap<Class<?>, Constructor<?>>();
/**
* Create an object for the given class and initialize it from conf
*
* @param theClass class of which an object is created
* @return a new object
*/
@SuppressWarnings("unchecked")
public static <T> T newInstance(Class<T> theClass) {
T result;
try {
Constructor<T> meth = (Constructor<T>) CONSTRUCTOR_CACHE.get(theClass);
if (meth == null) {
meth = theClass.getDeclaredConstructor(EMPTY_ARRAY);
meth.setAccessible(true);
CONSTRUCTOR_CACHE.put(theClass, meth);
}
result = meth.newInstance();
} catch (Exception e) {
throw new RuntimeException(e);
}
return result;
}
}