[Portal参考手册]Portlet服务框架

Poetlet服务封装了portlet中的可重用的商业和逻辑操作。Portlet服务有利于将逻辑操作最小化，便于重用。另一方面，portlet服务还有下面的好处：

内建的持久化框架有有利于将对象持久化到关系数据库中。

内建的访问控制权限有利于安全控制

集成测试框架

Spirit服务接口借用了websphere的接口。下面时服务的UML图：

<!--[if !vml]--><!--[endif]-->



PortletServiceFactory负责产生、初始化、销毁portlet服务。PortletService定义了一个空的服务接口，而PortletServiceProvider定义了增加了生命周期，当服务初始化和销毁的时候调用init和destroy方法。服务描述文件定义了服务和初始化参数。通过PortletServiceConfig这个类可以得到初始化参数。

              一个portlet可以通过PortletContext对象得到服务。getService()方法返回一个服务对象PortletService。

ExampleService =        (ExampleService)getPortletConfig().getContext().getService(ExampleService.class);

    用户服务时带有权限的服务，例如UserManagerService服务中的方法deleteUser(User user)只有超级用户才能执行，其他用户才会抛出PortletServiceAuthorizationException异常。



核心portlet服务

Spirit包含几个核心服务，这些服务有基本的portlet所调用。仅有LoginService不是用户服务。UserManagerService和AccessControlService都是用户服务。



    Portlet服务举例

    下面列举一个股票报价的服务StockQuoteService，这个服务只有一个方法getStockQuotes，返回从quote.com服务得到的股票报价列表。

    定义服务

    在WEB-INF/PortletServices.xml文件中定义一个服务实体：

    ...



        <service>

            <name>Stock Quote Service</name>

            <description>Provides Stock Quotes</description>

            <interface>org.myorg.services.StockQuoteService</interface>  

            <implementation>org.myorg.services.impl.StockQuoteServiceImpl</implementation>

            <service-config>

                <param-name>quote_service</param-name>

                <param-value>quote.com</param-value>

            </service-config>

        </service>

    定义服务接口

       package org.myorg.services.StockQuoteService;



    import com.kuaff.spirit.portlet.service;

    import java.util.List;



    public interface StockQuoteService extends PortletService { <!--[if !vml]--><!--[endif]-->



        public List getStockQuotes();  <!--[if !vml]--><!--[endif]-->



    }

<!--[if !vml]--><!--[endif]-->
StockQuoteService必须继承PortletService

<!--[if !vml]--><!--[endif]-->
定义了一个方法：getStockQuotes


   

    定义服务实现

    package org.myorg.services.impl.StockQuoteServiceImpl;



    import org.myorg.services.StockQuoteService;

    import com.kuaff.spirit.portlet.service.*;

    import com.kuaff.spirit.portlet.service.spi.PortletServiceProvider;

    import java.util.List;



    public class StockQuoteServiceImpl implements PortletServiceProvider, StockQuoteService {

        public void init(PortletServiceConfig config)      

                    throws PortletServiceUnavailableException {

            // 初始化

        }

        public void destroy() {                      

            // 销毁

        }

        public List getStockQuotes() {

            // 得到股票报价列表

        }

    }



    Portlet中访问服务

    package org.myorg.portlets.StockQuotePortlet;



    // 这里忽略了import



    public class StockQuotePortlet extends AbstractPortlet {



        public void actionPerformed(ActionEvent event) {

            PortletContext ctx = getPortletConfi().getContext();

            StockQuoteService quoteService = null;

            try {

                StockQuoteService quoteService = (StockQuoteService)ctx.getService(StockQuoteService.class);

            } catch (PortletServiceException e) {

                getPortletLog().error("Couldn't get quote service instance", e);

                return;

            }



            // 得到股票报价列表，并放到request中

            List quotes = quoteService.getStockQuotes();

            req.setAttribute("stocks", quotes);

        }



        public void doView(PortletRequest req, PortletResponse res) {



            // 显示股票报价

            List quotes = req.getAttribute("stocks");

            ...

        }



    }



    用户服务举例

    还是以上一个例子为例，假定只有管理员可以配置股票，这样StockQuoteService将变成了用户服务。

       定义用户服务

       仅仅增加了user-required元素

       <service>

            <name>Stock Quote Service</name>

            <user-required>true</user-required>

            <description>Provides Stock Quotes</description>

            <interface>org.myorg.services.StockQuoteService</interface>  

            <implementation>org.myorg.services.impl.StockQuoteServiceImpl</implementation>

            <service-config>

                <param-name>quote_service</param-name>

                <param-value>quote.com</param-value>

            </service-config>

        </service>

必须设置<user-required>true</user-required>

   

    编辑用户接口

    ...



        setQuoteService(String quoteService);



        ....

   

    定义用户服务实现

    package org.myorg.services.impl.StockQuoteServiceFactory;



    import org.myorg.services.StockQuoteService;

    import com.kuaff.spirit.portlet.service.*;

    import com.kuaff.spirit.portlet.service.spi.PortletServiceProvider;

    import java.util.List;



    public class StockQuoteServiceFactory implements PortletServiceProvider, StockQuoteService {



        // 产生单例

        private instance = new StockQuoteFactory();



        private StockQuoteServiceFactory() {}             



        public static StockQuoteServiceFactory getInstance() {

            return instance;

        }



        public void init(PortletServiceConfig config)

                throws PortletServiceUnavailableException {

            // 初始化

        }



        public void destroy() {

            // 销毁

        }



        public List getStockQuotes() {

            // 得到股票列表

        }



        public void setStockQuoteService(String quoteService) {

            // 设置股票服务

        }



    }

   

下一步就是对StockQuoteServiceImpl增加权限检查。

    package org.myorg.services.impl.StockQuoteServiceImpl;



    import org.myorg.services.StockQuoteService;

    import com.kuaff.spirit.portlet.services.*;

    import com.kuaff.spirit.portlet.services.spi.PortletServiceProvider;

    import java.util.List;



    public class StockQuoteServiceImpl implements PortletServiceProvider, StockQuoteService {



        private StockQuoteServiceFactory quoteServiceFactory = null;



        private PortletServiceAuthorizer authorizer = null;



        public UserManagerServiceImpl(PortletServiceAuthorizer authorizer) {

           this.authorizer = authorizer;

        }



        public void init(PortletServiceConfig config)

                    throws PortletServiceUnavailableException {

            // 使用StockQuoteServiceFactory配置

            quoteServiceFactory = StockQuoteServiceFactory.getInstance();

            quoteServiceFactory.init();

        }



        public void destroy() {

            // 销毁

            quoteServiceFactory.destroy();

        }



        public List getStockQuotes() {

            quoteServiceFactory.getStockQuotes();

        }



        public void setStockQuoteService(String quoteService) {     <!--[if !vml]--><!--[endif]-->

            // 设置股票服务



            //检查权限

            authorizer.authorizeSuperUser();



            quoteServiceFactory.setStockQuoteService(quoteService);

        }



    }

   

Portlet中访问用户服务

    ...



        public void actionPerformed(ActionEvent event) {

            PortletContext ctx = getPortletConfig().getContext();

            PortletRequest req = event.getPortletRequest();

            User user = req.getUser();

            StockQuoteService quoteService = null;

            try {

                StockQuoteService quoteService = (StockQuoteService)ctx.getService(StockQuoteService.class, user);

            } catch (PortletServiceException e) {

                getPortletLog().error("不能得到服务实例", e);

                return;

       

            List quotes = quoteService.getStockQuotes();

            req.setAttribute("stocks", quotes);

        }





        ....