netstoreservicefactory.java

网上商店 新增功能： 1

package netstore.service;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import org.apache.struts.action.PlugIn;
import org.apache.struts.action.ActionServlet;
import org.apache.struts.config.ModuleConfig;
import netstore.framework.util.IConstants;

/**
 * 实现工厂
 * 初始化参数默认从ServiceContext上下文获取，否则类中默认指定值
 * 注意此处使用了struts插件
 */
/**
 * A factory for creating Netstore Service Implementations. The specific service
 * to instantiate is determined from the initialization parameter of the
 * ServiceContext. Otherwise, a default implementation is used.
 * 
 * @see netstore.service.NetstoreDebugServiceImpl
 */
public class NetstoreServiceFactory implements INetstoreServiceFactory, PlugIn {
	// Hold onto the servlet for the destroy method
	private ActionServlet servlet = null;

	// The default is to use the debug implementation
	String serviceClassname = "netstore.service.NetstoreServiceImpl";

	String serviceOrderClassname = "netstore.service.OrderServiceImpl";

	String serviceCustClassname = "netstore.service.CustServiceImpl";

	String serviceProdClassname = "netstore.service.ProdServiceImpl";

	/**
	 * 上层类通过调用该方法，实际上就能得到业务代理实现类的对象 netstore.service.NetstoreServiceImpl
	 */
	public INetstoreService createService() throws ClassNotFoundException,
			IllegalAccessException, InstantiationException {
		// 以servlet中定义为准，如定义，则改写默认值
		String className = servlet
				.getInitParameter(IConstants.SERVICE_CLASS_KEY);
		if (className != null) {
			serviceClassname = className;
		}

		try {
			// java反射机制
			INetstoreService instance = (INetstoreService) Class.forName(
					serviceClassname).newInstance();

			instance.setServletContext(servlet.getServletContext());

			return instance;
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}

	}

	/**
	 * 获取客户服务类
	 */
	public CustServiceImpl createCustService() throws ClassNotFoundException,
			IllegalAccessException, InstantiationException {

		try {
			// java反射机制
			CustServiceImpl instance = (CustServiceImpl) Class.forName(
					serviceCustClassname).newInstance();

			instance.setServletContext(servlet.getServletContext());

			return instance;
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}

	/**
	 * 获取产品服务类
	 */
	public ProdServiceImpl createProdService() throws ClassNotFoundException,
			IllegalAccessException, InstantiationException {

		try {
			// java反射机制
			ProdServiceImpl instance = (ProdServiceImpl) Class.forName(
					serviceProdClassname).newInstance();

			instance.setServletContext(servlet.getServletContext());

			return instance;
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}

	/**
	 * 获取订单服务类
	 */
	public OrderServiceImpl createOrderService() throws ClassNotFoundException,
			IllegalAccessException, InstantiationException {

		try {
			// java反射机制
			OrderServiceImpl instance = (OrderServiceImpl) Class.forName(
					serviceOrderClassname).newInstance();

			instance.setServletContext(servlet.getServletContext());

			return instance;
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
	}

	public void init(ActionServlet servlet, ModuleConfig config)
			throws ServletException {
		// Store the servlet for later
		// 加载servlet进来
		this.servlet = servlet;

		/*
		 * Store the factory for the application. Any Netstore service factory
		 * must either store itself in the ServletContext at this key, or extend
		 * this class and don't override this method. The Netstore application
		 * assumes that a factory class that implements the
		 * IStorefrtonServiceFactory is stored at the proper key in the
		 * ServletContext. 存储工厂实现于Servlet
		 */
		servlet.getServletContext().setAttribute(
				IConstants.SERVICE_FACTORY_KEY, this);
	}

	public void destroy() {
		// Do nothing for now
	}
}