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clarified flow controller vs flow handler

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Scott Andrews
2008-04-11 14:06:10 +00:00
parent e6a6862698
commit 875b4c304a
1 changed files with 32 additions and 22 deletions
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54
spring-webflow-reference/src/spring-mvc.xml
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@@ -55,19 +55,30 @@
]]></programlisting>
<para>
For this example both a standard MVC controller and a Web Flow handler are configured.
The controller supports the free navigation aspects of searching and viewing hotels.
The flow handler supports the controlled navigation aspect of booking a hotel room.
The <code>hotelsController</code> supports the free navigation aspects of searching and viewing hotels.
The <code>bookingFlowHandler</code> supports the controlled navigation aspect of booking a hotel room.
</para>
</sect2>
<sect2 id="spring-mvc-config-spring-flow-controllers">
<title>Flow Controllers</title>
<para>
Flow controllers provide a basic hook from Spring MVC into Web Flow.
The <code>FlowController</code> class is an implementation of an MVC Controller.
</para>
<programlisting language="xml"><![CDATA[
<bean id="flowController" class="org.springframework.webflow.mvc.servlet.FlowController">
<constructor-arg ref="flowExecutor"/>
</bean>
]]></programlisting>
<para>
Web Flow 1.0 used controllers as the only way to hook Web Flow into Spring MVC.
With Web Flow 2.0 flow controllers should be used when the flow is self contained and does not need to interact with the environment.
</para>
</sect2>
<sect2 id="spring-mvc-config-spring-flow-adapters">
<title>Flow Adapters</title>
<para>
The recommended way to bridge Spring MVC requests to Web Flow is via a flow adapter.
</para>
<programlisting language="xml"><![CDATA[
<bean id="bookingFlowHandler" class="org.springframework.webflow.samples.booking.BookingFlowHandler" />
]]></programlisting>
<para>
Flow adapters provide a richer integration point between Spring MVC and Web Flow.
The flow adapter provides hooks into the flow execution that can:
<itemizedlist>
<listitem>
@@ -83,30 +94,29 @@
<para>handle any exceptions</para>
</listitem>
</itemizedlist>
</para>
<para>
A flow handler should be used whenever integration with any of these hooks is desired.
</para>
<para>
The <code>AbstractFlowHandler</code> class is an implementation of <code>FlowHandler</code> that provides default implementations for these hooks.
</para>
<para>
A common pattern to handle a flow outcome is to redirect to a new page instead of rendering a view in the <code>end-state</code>.
This allows the URL to be refreshed without throwing an exception.
</para>
<programlisting language="xml"><![CDATA[
<bean id="bookingFlowHandler"
class="org.springframework.webflow.samples.booking.BookingFlowHandler" />
]]></programlisting>
<programlisting language="java"><![CDATA[
public class BookingFlowHandler extends AbstractFlowHandler {
public ModelAndView handleExecutionOutcome(String outcome, AttributeMap output, HttpServletRequest request, HttpServletResponse response) {
return new ModelAndView(new RedirectView("/spring/hotels/index", true));
}
public ModelAndView handleExecutionOutcome(String outcome, AttributeMap output,
HttpServletRequest request, HttpServletResponse response) {
return new ModelAndView(new RedirectView("/spring/hotels/index", true));
}
}
]]></programlisting>
</sect2>
<sect2 id="spring-mvc-config-spring-flow-controllers">
<title>Flow Controllers</title>
<para>
Flow controllers provide a direct hook from Spring MVC into Web Flow.
The <code>FlowController</code> class is an implementation of an MVC Controller.
</para>
<para>
Web Flow 1.0 used controllers as the only way to hook Web Flow into Spring MVC.
In Web Flow 2.0 flow handler adapters are recommended instead of controllers as they provide much richer hooks into the web flow engine.
</para>
</sect2>
</sect1>
</chapter>