org.springframework.beans.factory.support.InstantiationStrategy.java Source code

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/*
 * Copyright 2002-2018 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
 *
 *      https://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.beans.factory.support;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.lang.Nullable;

/**
 * Interface responsible for creating instances corresponding to a root bean definition.
 *
 * <p>This is pulled out into a strategy as various approaches are possible,
 * including using CGLIB to create subclasses on the fly to support Method Injection.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @since 1.1
 */
public interface InstantiationStrategy {

    /**
     * Return an instance of the bean with the given name in this factory.
     * @param bd the bean definition
     * @param beanName the name of the bean when it is created in this context.
     * The name can be {@code null} if we are autowiring a bean which doesn't
     * belong to the factory.
     * @param owner the owning BeanFactory
     * @return a bean instance for this bean definition
     * @throws BeansException if the instantiation attempt failed
     */
    Object instantiate(RootBeanDefinition bd, @Nullable String beanName, BeanFactory owner) throws BeansException;

    /**
     * Return an instance of the bean with the given name in this factory,
     * creating it via the given constructor.
     * @param bd the bean definition
     * @param beanName the name of the bean when it is created in this context.
     * The name can be {@code null} if we are autowiring a bean which doesn't
     * belong to the factory.
     * @param owner the owning BeanFactory
     * @param ctor the constructor to use
     * @param args the constructor arguments to apply
     * @return a bean instance for this bean definition
     * @throws BeansException if the instantiation attempt failed
     */
    Object instantiate(RootBeanDefinition bd, @Nullable String beanName, BeanFactory owner, Constructor<?> ctor,
            Object... args) throws BeansException;

    /**
     * Return an instance of the bean with the given name in this factory,
     * creating it via the given factory method.
     * @param bd the bean definition
     * @param beanName the name of the bean when it is created in this context.
     * The name can be {@code null} if we are autowiring a bean which doesn't
     * belong to the factory.
     * @param owner the owning BeanFactory
     * @param factoryBean the factory bean instance to call the factory method on,
     * or {@code null} in case of a static factory method
     * @param factoryMethod the factory method to use
     * @param args the factory method arguments to apply
     * @return a bean instance for this bean definition
     * @throws BeansException if the instantiation attempt failed
     */
    Object instantiate(RootBeanDefinition bd, @Nullable String beanName, BeanFactory owner,
            @Nullable Object factoryBean, Method factoryMethod, Object... args) throws BeansException;

}