org.springframework.objenesis.ObjenesisBase Maven / Gradle / Ivy
/*
* Copyright 2006-2022 the original author or authors.
*
* 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.springframework.objenesis;
import org.springframework.objenesis.instantiator.ObjectInstantiator;
import org.springframework.objenesis.strategy.InstantiatorStrategy;
import java.util.concurrent.ConcurrentHashMap;
/**
* Base class to extend if you want to have a class providing your own default strategy. Can also be
* instantiated directly.
*
* @author Henri Tremblay
*/
public class ObjenesisBase implements Objenesis {
/** Strategy used by this Objenesis implementation to create classes */
protected final InstantiatorStrategy strategy;
/** Strategy cache. Key = Class, Value = InstantiatorStrategy */
protected ConcurrentHashMap> cache;
/**
* Constructor allowing to pick a strategy and using cache
*
* @param strategy Strategy to use
*/
public ObjenesisBase(InstantiatorStrategy strategy) {
this(strategy, true);
}
/**
* Flexible constructor allowing to pick the strategy and if caching should be used
*
* @param strategy Strategy to use
* @param useCache If {@link ObjectInstantiator}s should be cached
*/
public ObjenesisBase(InstantiatorStrategy strategy, boolean useCache) {
if(strategy == null) {
throw new IllegalArgumentException("A strategy can't be null");
}
this.strategy = strategy;
this.cache = useCache ? new ConcurrentHashMap<>() : null;
}
@Override
public String toString() {
return getClass().getName() + " using " + strategy.getClass().getName()
+ (cache == null ? " without" : " with") + " caching";
}
/**
* Will create a new object without any constructor being called
*
* @param clazz Class to instantiate
* @return New instance of clazz
*/
public T newInstance(Class clazz) {
return getInstantiatorOf(clazz).newInstance();
}
/**
* Will pick the best instantiator for the provided class. If you need to create a lot of
* instances from the same class, it is way more efficient to create them from the same
* ObjectInstantiator than calling {@link #newInstance(Class)}.
*
* @param clazz Class to instantiate
* @return Instantiator dedicated to the class
*/
@SuppressWarnings("unchecked")
public ObjectInstantiator getInstantiatorOf(Class clazz) {
if(clazz.isPrimitive()) {
throw new IllegalArgumentException("Primitive types can't be instantiated in Java");
}
if(cache == null) {
return strategy.newInstantiatorOf(clazz);
}
ObjectInstantiator instantiator = cache.get(clazz.getName());
if(instantiator == null) {
ObjectInstantiator newInstantiator = strategy.newInstantiatorOf(clazz);
instantiator = cache.putIfAbsent(clazz.getName(), newInstantiator);
if(instantiator == null) {
instantiator = newInstantiator;
}
}
return (ObjectInstantiator) instantiator;
}
}