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Keith Donald
2008-07-28 15:36:37 +00:00
parent 808bdabe6f
commit 6ce86e2712
1 changed files with 101 additions and 4 deletions
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spring-webflow-reference/src/views.xml
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@@ -143,19 +143,22 @@
<title>Binding to a model</title>
<para>
Use the <code>model</code> attribute to declare a model object the view binds to.
This attribute is typically used with views that render data controls, such as forms.
This attribute is typically used in conjunction with views that render data controls, such as forms.
It enables form data binding and validation behaviors to be driven from metadata on your model object.
</para>
<para>
The following example declares an <code>enterBookingDetails</code> state manipulates the <code>booking</code> model:
</para>
<programlisting language="xml"><![CDATA[
<view-state id="enterBookingDetails" model="booking">]]>
</programlisting>
<para>
The model may be in any accessible scope, such as <code>flowScope</code> or <code>viewScope</code>.
The model may an object in any accessible scope, such as <code>flowScope</code> or <code>viewScope</code>.
Specifying a <code>model</code> triggers the following behavior when a view event occurs:
</para>
<orderedlist>
<listitem><para>View-to-model binding. On view postback, form values are bound to model object properties for you.</para></listitem>
<listitem><para>Model validation. After binding, if the model object requires validation, that validation logic will be invoked.</para></listitem>
<listitem><para>View-to-model binding. On view postback, user input values are bound to model object properties for you.</para></listitem>
<listitem><para>Model validation. After binding, if the model object requires validation that validation logic will be invoked.</para></listitem>
</orderedlist>
<para>
For a flow event to be generated that can drive a view state transition, model binding must complete successfully.
@@ -166,6 +169,7 @@
<title>Suppressing binding</title>
<para>
Use the <code>bind</code> attribute to suppress model binding and validation for particular view events.
The following example suppresses binding when the <code>cancel</code> event occurs:
</para>
<programlisting language="xml"><![CDATA[
<view-state id="enterBookingDetails" model="booking">
@@ -174,6 +178,76 @@
</view-state>]]>
</programlisting>
</sect1>
<sect1 id="view-binder">
<title>Specifying bindings explicitly</title>
<para>
Use the <code>binder</code> element to configure the exact set of model bindings usable by the view.
This is particularly useful in a Spring MVC environment for restricting the set of "allowed fields" per view.
</para>
<programlisting language="xml"><![CDATA[
<view-state id="enterBookingDetails" model="booking">
<binder>
<binding property="creditCard" />
<binding property="creditCardName" />
<binding property="creditCardExpiryMonth" />
<binding property="creditCardExpiryYear" />
</binder>
<transition on="proceed" to="reviewBooking" />
<transition on="cancel" to="cancel" bind="false" />
</view-state>
]]>
</programlisting>
<para>
If the binder element is not specified, all public properties of the model are eligible for binding by the view.
With the binder element specified, only the explicitly configured bindings are allowed.
</para>
<para>
Each binding may also apply a converter to format the model property value for display in a custom manner.
If no converter is specified, the default converter for the model property's type will be used.
</para>
<programlisting language="xml"><![CDATA[
<view-state id="enterBookingDetails" model="booking">
<binder>
<binding property="checkinDate" converter="shortDate" />
<binding property="checkoutDate" converter="shortDate" />
<binding property="creditCard" />
<binding property="creditCardName" />
<binding property="creditCardExpiryMonth" />
<binding property="creditCardExpiryYear" />
</binder>
<transition on="proceed" to="reviewBooking" />
<transition on="cancel" to="cancel" bind="false" />
</view-state>
]]>
</programlisting>
<para>
In the example above, the <code>shortDate</code> converter is bound to the
<code>checkinDate</code> and <code>checkoutDate</code> properties.
Custom converters may be registered with the application's ConversionService.
</para>
<para>
Each binding may also apply a required check that will generate a validation error
if the user provided value is null on form postback:
</para>
<programlisting language="xml"><![CDATA[
<view-state id="enterBookingDetails" model="booking">
<binder>
<binding property="checkinDate" converter="shortDate" required="true" />
<binding property="checkoutDate" converter="shortDate" required="true" />
<binding property="creditCard" required="true" />
<binding property="creditCardName" required="true" />
<binding property="creditCardExpiryMonth" required="true" />
<binding property="creditCardExpiryYear" required="true" />
</binder>
<transition on="proceed" to="reviewBooking">
<transition on="cancel" to="bookingCancelled" bind="false" />
</view-state>]]>
</programlisting>
<para>
In the example above, all of the bindings are required.
If one or more blank input values are bound, validation errors will be generated and the view will re-render with those errors.
</para>
</sect1>
<sect1 id="view-validate">
<title>Validating a model</title>
<para>
@@ -238,7 +312,30 @@ public class BookingValidator {
</para>
</sect3>
</sect2>
<sect2 id="view-validation-declarative">
<title>Declarative validation</title>
<para>
Spring Web Flow does not yet ship integration with a declarative validation framework such as Hibernate Validator.
It is expected that integration will be provided in a future Web Flow release.
This integration will allow declarative validation constraints to be defined against model properties.
</para>
</sect2>
</sect1>
<sect1 id="view-validation-suppression">
<title>Suppressing validation</title>
<para>
Use the <code>validate</code> attribute to suppress model validation for particular view events:
</para>
<programlisting language="xml"><![CDATA[
<view-state id="chooseAmenities" model="booking">
<transition on="proceed" to="reviewBooking">
<transition on="back" to="enterBookingDetails" validate="false" />
</view-state>]]>
</programlisting>
<para>
In this example, data binding will still occur on <code>back</code> but validation will be suppressed.
</para>
</sect1>
<sect1 id="transition-actions">
<title>Transition actions</title>
<para>