core/src/main/java/org/apache/commons/proxy2/provider/BeanProvider.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.commons.proxy2.provider;

import java.io.Serializable;

import org.apache.commons.lang3.Validate;
import org.apache.commons.proxy2.ObjectProvider;
import org.apache.commons.proxy2.exception.ObjectProviderException;

/**
 * Uses <code>Class.newInstance()</code> to instantiate an object.
 * 
 * @author James Carman
 * @since 1.0
 */
public class BeanProvider<T> implements ObjectProvider<T>, Serializable
{
    /** Serialization version */
    private static final long serialVersionUID = 1L;

    //******************************************************************************************************************
    // Fields
    //******************************************************************************************************************

    private final Class<? extends T> beanClass;

    //******************************************************************************************************************
    // Constructors
    //******************************************************************************************************************

    /**
     * Constructs a provider which instantiates objects of the specified bean class.
     * 
     * @param beanClass
     *            the bean class
     */
    public BeanProvider(Class<? extends T> beanClass)
    {
        Validate.notNull(beanClass, "Bean class cannot be null.");
        this.beanClass = beanClass;
    }

    //******************************************************************************************************************
    // ObjectProvider Implementation
    //******************************************************************************************************************

    /**
     * {@inheritDoc}
     */
    @Override
    public T getObject()
    {
        try
        {
            return beanClass.newInstance();
        }
        catch (InstantiationException e)
        {
            throw new ObjectProviderException(e, "%s is not concrete.", beanClass);
        }
        catch (IllegalAccessException e)
        {
            throw new ObjectProviderException(e, "Constructor for %s is not accessible.", beanClass);
        }
    }
}