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

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Here is the source code for org.springframework.beans.factory.support.SimpleInstantiationStrategy.java

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/*
 * Copyright 2002-2006 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.beans.factory.support;

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

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.BeanDefinitionStoreException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.util.StringUtils;

/**
 * Simple object instantiation strategy for use in a BeanFactory.
 *
 * <p>Does not support Method Injection, although it provides hooks for subclasses
 * to override to add Method Injection support, for example by overriding methods.
 *
 * @author Rod Johnson
 * @since 1.1
 */
public class SimpleInstantiationStrategy implements InstantiationStrategy {

    /** Logger available to subclasses */
    protected final Log logger = LogFactory.getLog(getClass());

    public Object instantiate(RootBeanDefinition beanDefinition, String beanName, BeanFactory owner) {

        // Don't override the class with CGLIB if no overrides.
        if (beanDefinition.getMethodOverrides().isEmpty()) {
            return BeanUtils.instantiateClass(beanDefinition.getBeanClass());
        } else {
            // Must generate CGLIB subclass.
            return instantiateWithMethodInjection(beanDefinition, beanName, owner);
        }
    }

    /**
     * Subclasses can override this method, which is implemented to throw
     * UnsupportedOperationException, if they can instantiate an object with
     * the Method Injection specified in the given RootBeanDefinition.
     * Instantiation should use a no-arg constructor.
     */
    protected Object instantiateWithMethodInjection(RootBeanDefinition beanDefinition, String beanName,
            BeanFactory owner) {

        throw new UnsupportedOperationException("Method Injection not supported in SimpleInstantiationStrategy");
    }

    public Object instantiate(RootBeanDefinition beanDefinition, String beanName, BeanFactory owner,
            Constructor ctor, Object[] args) {

        if (beanDefinition.getMethodOverrides().isEmpty()) {
            return BeanUtils.instantiateClass(ctor, args);
        } else {
            return instantiateWithMethodInjection(beanDefinition, beanName, owner, ctor, args);
        }
    }

    /**
     * Subclasses can override this method, which is implemented to throw
     * UnsupportedOperationException, if they can instantiate an object with
     * the Method Injection specified in the given RootBeanDefinition.
     * Instantiation should use the given constructor and parameters.
     */
    protected Object instantiateWithMethodInjection(RootBeanDefinition beanDefinition, String beanName,
            BeanFactory owner, Constructor ctor, Object[] args) {

        throw new UnsupportedOperationException("Method Injection not supported in SimpleInstantiationStrategy");
    }

    public Object instantiate(RootBeanDefinition beanDefinition, String beanName, BeanFactory owner,
            Object factoryBean, Method factoryMethod, Object[] args) {

        try {
            // It's a static method if the target is null.
            if (!Modifier.isPublic(factoryMethod.getModifiers())
                    || !Modifier.isPublic(factoryMethod.getDeclaringClass().getModifiers())) {
                factoryMethod.setAccessible(true);
            }
            return factoryMethod.invoke(factoryBean, args);
        } catch (IllegalArgumentException ex) {
            throw new BeanDefinitionStoreException("Illegal arguments to factory method [" + factoryMethod + "]; "
                    + "args: " + StringUtils.arrayToCommaDelimitedString(args));
        } catch (IllegalAccessException ex) {
            throw new BeanDefinitionStoreException(
                    "Cannot access factory method [" + factoryMethod + "]; is it public?");
        } catch (InvocationTargetException ex) {
            String msg = "Factory method [" + factoryMethod + "] threw exception";
            // We want to log this one, as it may be a config error:
            // the method may match, but may have been given incorrect arguments.
            logger.warn(msg, ex.getTargetException());
            throw new BeanDefinitionStoreException(msg, ex.getTargetException());
        }
    }

}