SimpleInstantiationStrategy.java

package org.theonefx.wcframework.ioc;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedExceptionAction;

import org.theonefx.wcframework.core.ClassWrapper;
import org.theonefx.wcframework.core.exception.BeanDefinitionStoreException;
import org.theonefx.wcframework.ioc.exception.BeanInstantiationException;
import org.theonefx.wcframework.utils.BeanUtils;
import org.theonefx.wcframework.utils.ReflectionUtils;
import org.theonefx.wcframework.utils.StringUtils;

public class SimpleInstantiationStrategy implements InstantiationStrategy {

	@Override
	public Object instantiate(ClassWrapper<?> classWrapper, RootBeanDefinition beanDefinition, String beanName) {
		Constructor<?> constructorToUse;
		synchronized (beanDefinition.constructorArgumentLock) {
			constructorToUse = (Constructor<?>) beanDefinition.resolvedConstructorOrFactoryMethod;
			if (constructorToUse == null) {
				final Class<?> clazz = classWrapper.getWrapperedClass();
				if (clazz.isInterface()) {
					throw new BeanInstantiationException(clazz, "给定的Class是一个Interface");
				}
				try {
					if (System.getSecurityManager() != null) {
						constructorToUse = AccessController.doPrivileged(new PrivilegedExceptionAction<Constructor<?>>() {
							public Constructor<?> run() throws Exception {
								return clazz.getDeclaredConstructor((Class[]) null);
							}
						});
					} else {
						constructorToUse = clazz.getDeclaredConstructor((Class[]) null);
					}
					beanDefinition.resolvedConstructorOrFactoryMethod = constructorToUse;
				} catch (Exception ex) {
					throw new BeanInstantiationException(clazz, "没有找到无参构造函数", ex);
				}
			}
		}
		return BeanUtils.instantiateClass(constructorToUse);
	}

	@Override
	public Object instantiate(ClassWrapper<?> classWrapper, RootBeanDefinition beanDefinition, String beanName, BeanFactory owner, final Constructor<?> ctor, Object[] args) {
		if (System.getSecurityManager() != null) {
			AccessController.doPrivileged(new PrivilegedAction<Object>() {
				public Object run() {
					ReflectionUtils.makeAccessible(ctor);
					return null;
				}
			});
		}
		return BeanUtils.instantiateClass(ctor, args);
	}

	@Override
	public Object instantiate(ClassWrapper<?> classWrapper, RootBeanDefinition beanDefinition, String beanName, BeanFactory owner, Object factoryBean, final Method factoryMethod, Object[] args) {
		try {
			if (System.getSecurityManager() != null) {
				AccessController.doPrivileged(new PrivilegedAction<Object>() {
					public Object run() {
						ReflectionUtils.makeAccessible(factoryMethod);
						return null;
					}
				});
			} else {
				ReflectionUtils.makeAccessible(factoryMethod);
			}

			// 如果factoryBean是null的话那么这个factoryMethod就必须是static的
			return factoryMethod.invoke(factoryBean, args);
		} catch (IllegalArgumentException ex) {
			throw new BeanDefinitionStoreException("应用于工厂方法 [" + factoryMethod + "]的参数非法; " + "参数: "
					+ StringUtils.arrayToCommaDelimitedString(args));
		} catch (IllegalAccessException ex) {
			throw new BeanDefinitionStoreException("方法 [" + factoryMethod + "]无法访问，你确定这个是public的吗？");
		} catch (InvocationTargetException ex) {
			throw new BeanDefinitionStoreException("调用工厂方法 [" + factoryMethod + "] 时发生异常", ex.getTargetException());
		}
	}
}