sakai项目中chat子模块解读

1、首先根据Sakai开发说明.pdf上面说的所有逻辑都必须都必须打包在sakai容器中，而打包到sakai容器中则是靠pack包来实现的，所以最开始先看一下components.xml文件，所在位置是chat/chat-impl/pack/src/webapp/WEB-INF/components.xml，也是spring框架需要的。

    <bean id="org.sakaiproject.chat2.model.ChatHibernateBean"
        class="org.sakaiproject.springframework.orm.hibernate.impl.AdditionalHibernateMappingsImpl">
        <property name="mappingResources">
            <list>
                <value>
                    org/sakaiproject/chat2/model/impl/ChatImpl.hbm.xml
                </value>
            </list>
        </property>
    </bean>

1.1、hibernate数据库映射，ChatImpl.hbm.xml主要包含内容：

<hibernate-mapping package="org.sakaiproject.chat2.model"
	default-lazy="true">

	<class name="ChatChannel" table="CHAT2_CHANNEL" lazy="true">

		<id name="id" length="99" column="CHANNEL_ID">
			<generator class="org.sakaiproject.id.hbm.IdGenerator"/>
		</id>

		<property name="title" type="string" length="64" />
		<property name="description" type="string" length="255" />
<span style="white-space:pre">		</span>...
		<property name="migratedChannelId" type="string" length="99" />

	</class>
	
	<class name="ChatMessage" table="CHAT2_MESSAGE" lazy="true">

		<id name="id" length="99" column="MESSAGE_ID">
			<generator class="org.sakaiproject.id.hbm.IdGenerator"/>
		</id>
		<property name="body" column="BODY" type="text" not-null="true" />
		...
	</class>

	<query name="findChannelsInContext">
		from ChatChannel c WHERE c.context=? order by c.title

主要包含两个bean（POJO）和一些sql查询语句的定义，其中ChatChannel和ChatMessage是数据库映射关系bean类，这两个java文件可以在chat/chat-api/src/.../model中找到，至于这些查询语句？？？

1.2、Spring中TransactionproxyFactoryBean生成事务代理

    <bean id="org.sakaiproject.chat2.model.ChatManager"
        class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">
        <property name="transactionManager">
            <ref bean="org.sakaiproject.springframework.orm.hibernate.GlobalTransactionManager" />
        </property>
        <property name="target">
            <ref bean="org.sakaiproject.chat2.model.impl.ChatManagerImpl" />
        </property>
        <property name="transactionAttributes">
            <props>
                <prop key="*">PROPAGATION_REQUIRED</prop>
            </props>
        </property>
    </bean>

    <bean id="org.sakaiproject.chat2.model.impl.ChatManagerImpl"
    	class="org.sakaiproject.chat2.model.impl.ChatManagerImpl"
    	singleton="true" init-method="init" destroy-method="destroy">
    	<property name="sessionFactory">
    		<ref
    			bean="org.sakaiproject.springframework.orm.hibernate.GlobalSessionFactory" />
    	</property>
    	<property name="entityManager">
    		<ref bean="org.sakaiproject.entity.api.EntityManager" />
    	</property>
    	<property name="defaultChannelSettings">
    		<ref bean="defaultChatChannelSettings" />
    	</property>
    </bean>

可以看出生成事务代理需要两个bean，一个是代理类TransactionproxyFactoryBean，另外一个是被代理类ChatManagerImpl，该被代理类可以在chat/chat-impl/impl/src/.../impl/下找到

1.3、其他逻辑类

	<bean id="org.sakaiproject.chat2.model.impl.ChatChannelEntityProvider"
		class="org.sakaiproject.chat2.model.impl.ChatChannelEntityProvider">
      <property name="chatManager"><ref bean="org.sakaiproject.chat2.model.ChatManager"/></property>
	</bean>

	<bean id="org.sakaiproject.chat2.model.impl.ChatMessageEntityProvider"
		class="org.sakaiproject.chat2.model.impl.ChatMessageEntityProvider">
      <property name="chatManager"><ref bean="org.sakaiproject.chat2.model.ChatManager"/></property>
	</bean>

这些类都可以在chat/chat-impl/impl/src/.../impl/下找到

1.4、为什么bean类（api中）

    <bean id="defaultChatChannelSettings" 
    		class="org.sakaiproject.chat2.model.ChatChannel"
    		singleton="true">
    	<property name="filterType">
    		<bean id="org.sakaiproject.chat2.model.ChatChannel.FILTER_ALL"
               class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean">
         </bean>
      </property>
    	<property name="filterParam"><value>3</value></property>
    	<property name="timeParam"><value>3</value></property>
    	<property name="numberParam"><value>10</value></property>
    	<property name="enableUserOverride"><value>true</value></property>
    </bean>

这个是干嘛的暂时还不知道

1.5、总结

chat/chat-impl/pack/src中只有一个一个components.xml文件，所以在将所有逻辑放到sakai容器中的时候会根据该文件进行，它包含的内容主要是api和impl中的内容

2、chat-tools主要是将war文件部署在webapp上，所以除了业务逻辑之外还需要处理页面关系等内容，他的大致结构图如下：

2.1、第①部分，主要是一些java工具类，一般供JSF使用？？？

2.2、第②部分主要是注册工具，例如sakai.chat.xml文件内容如下

<registration>

	<tool
			id="sakai.chat"
			title="Chat Room"
			description="For real-time conversations in written form.">

		<configuration name="display-date" value="false" />
		<configuration name="display-time" value="true" />
		<configuration name="display-user" value="true" />
		<configuration name="sound-alert" value="true" />
		<configuration name="filter-type" value="SelectMessagesByTime" />
		<configuration name="filter-param" value="3" />
		<configuration name="channel" value="" />

		<category name="course" />
		<category name="project" />

		<configuration name="functions.require" value="chat.read" /> 

	</tool>

</registration>

其中最主要的是id/title，还有category，其中category表示该工具在哪个site下面展现

2.3、第③部分faces.config.xml文件，因为sakai使用的JSF框架，该文件就是JSF框架的关键配置文件。

2.3.1、application，指的是用于管理JSF应用的相关配置，ChatNavigationHandler就是2.1中的内容

  <application>
    <message-bundle>chat</message-bundle>
    <locale-config>
      <default-locale>en</default-locale>
    </locale-config>
    <navigation-handler>
    	org.sakaiproject.chat2.tool.ChatNavigationHandler
    </navigation-handler>
  </application>

2.3.2、managed-bean，JSF中所有托管的bean，其中的ChatTool也是2.1中的内容

<managed-bean>
        <description>ChatTool</description>
        <managed-bean-name>ChatTool</managed-bean-name>
        <managed-bean-class>org.sakaiproject.chat2.tool.ChatTool</managed-bean-class>
        <managed-bean-scope>session</managed-bean-scope>

        <managed-property>
            <description>chatManager</description>
            <property-name>chatManager</property-name>
            <value>#{Components["org.sakaiproject.chat2.model.ChatManager"]}</value>
        </managed-property>

      	<managed-property>
      	   <description>Service Dependency: toolManager</description>
           <property-name>toolManager</property-name>
           <value>#{Components["org.sakaiproject.tool.api.ActiveToolManager"]}</value>
        </managed-property>
    </managed-bean>

2.3.3、navigation-rule，管理JSF应用的导航规则

<navigation-rule>
    <from-view-id>*</from-view-id>
    <navigation-case>
      <from-outcome>room</from-outcome>
      <to-view-id>/jsp/room.jsp</to-view-id>
      <redirect/>
    </navigation-case>
    <navigation-case><!-- not needed if using the courier -->
      <from-outcome>roomActions</from-outcome>
      <to-view-id>/jsp/roomActions.jsp</to-view-id>
      <redirect/>
    </navigation-case>
    ...
  </navigation-rule>

2.4、第④部分，web.xml

2.4.1、filter-mapping内容，有3个，刚好对应第②部分

     <filter-mapping>
        <filter-name>sakai.request</filter-name>
        <servlet-name>sakai.chat</servlet-name>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
        <dispatcher>INCLUDE</dispatcher>
    </filter-mapping>
    
    <filter-mapping>
        <filter-name>sakai.request</filter-name>
        <servlet-name>sakai.synoptic.chat</servlet-name>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
        <dispatcher>INCLUDE</dispatcher>
    </filter-mapping>
    
    <filter-mapping>
        <filter-name>sakai.request</filter-name>
        <servlet-name>sakai.chat.deleteMessage</servlet-name>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
        <dispatcher>INCLUDE</dispatcher>
    </filter-mapping>

2.4.2、servlet内容，也有4个，其中有3个也是对应于第②部分

     <servlet>
      <servlet-name>sakai.synoptic.chat</servlet-name>
      <servlet-class>org.sakaiproject.jsf.util.HelperAwareJsfTool</servlet-class>
        <init-param>
            <param-name>path</param-name>
            <param-value>/jsp</param-value>
        </init-param>

        <init-param>
            <param-name>default</param-name>
            <!-- the path is inserted before and .jsp inserted after -->
            <param-value>synoptic</param-value>
        </init-param>
         <init-param>
            <param-name>default.last.view</param-name>
            <param-value>false</param-value>
        </init-param>
      <load-on-startup>1</load-on-startup>
   </servlet>

另外一个如下：

    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup> 2 </load-on-startup>
    </servlet>

FacesServlet是JSF核心控制器

2.5、最后部署的war文件