io.datarouter.binarydto.internal.BinaryDtoAllocator Maven / Gradle / Ivy
/*
* Copyright © 2009 HotPads ([email protected])
*
* 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 io.datarouter.binarydto.internal;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import io.datarouter.binarydto.dto.BaseBinaryDto;
/**
* Borrowed from Gson's UnsafeAllocator
*
* Allows instantiation of BinaryDtos without a no-arg constructor. A no-arg constructor complicates the encouraged use
* of final fields.
*/
public class BinaryDtoAllocator{
private static final UnsafeAllocator ALLOCATOR = new UnsafeAllocator();
public static > T allocate(Class cls){
return ALLOCATOR.allocate(cls);
}
private static class UnsafeAllocator{
private final Object unsafe;
private final Method allocateInstance;
public UnsafeAllocator(){
try{
Class unsafeClass = Class.forName("sun.misc.Unsafe");
Field theUnsafeField = unsafeClass.getDeclaredField("theUnsafe");
theUnsafeField.setAccessible(true);
unsafe = theUnsafeField.get(null);
allocateInstance = unsafeClass.getMethod("allocateInstance", Class.class);
}catch(Exception e){
throw new RuntimeException(e);
}
}
@SuppressWarnings("unchecked")
public T allocate(Class cls){
try{
return (T)allocateInstance.invoke(unsafe, cls);
}catch(Exception e){
throw new RuntimeException(e);
}
}
}
}