lightning-core/src/main/java/org/apache/directmemory/lightning/internal/instantiator/basic/ObjectStreamClassInstantiator.java

/*
 * 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.apache.directmemory.lightning.internal.instantiator.basic;

import java.io.ObjectStreamClass;
import java.lang.reflect.Method;

import org.apache.directmemory.lightning.instantiator.ObjectInstantiator;
import org.apache.directmemory.lightning.internal.instantiator.ObjenesisException;

/**
 * Instantiates a class by using reflection to make a call to private method ObjectStreamClass.newInstance, present in
 * many JVM implementations. This instantiator will create classes in a way compatible with serialization, calling the
 * first non-serializable superclass' no-arg constructor.
 * 
 * @author Leonardo Mesquita
 * @see ObjectInstantiator
 * @see java.io.Serializable
 */
public class ObjectStreamClassInstantiator
    implements ObjectInstantiator
{

    private static Method newInstanceMethod;

    private static void initialize()
    {
        if ( newInstanceMethod == null )
        {
            try
            {
                newInstanceMethod = ObjectStreamClass.class.getDeclaredMethod( "newInstance", new Class[] {} );
                newInstanceMethod.setAccessible( true );
            }
            catch ( RuntimeException e )
            {
                throw new ObjenesisException( e );
            }
            catch ( NoSuchMethodException e )
            {
                throw new ObjenesisException( e );
            }
        }
    }

    private final ObjectStreamClass objStreamClass;

    public ObjectStreamClassInstantiator( Class<?> type )
    {
        initialize();
        objStreamClass = ObjectStreamClass.lookup( type );
    }

    @Override
    public Object newInstance()
    {
        try
        {
            return newInstanceMethod.invoke( objStreamClass, new Object[] {} );
        }
        catch ( Exception e )
        {
            throw new ObjenesisException( e );
        }
    }
}