[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);

}





....