Apache Struts 2 Documentation > Home > Guides > Core Developers Guide > Interceptors > Validation Interceptor
#editReport()

This interceptor runs the action through the standard validation framework, which in turn checks the action against any validation rules (found in files such as ActionClass-validation.xml) and adds field-level and action-level error messages (provided that the action implements com.opensymphony.xwork2.ValidationAware). This interceptor is often one of the last (or second to last) interceptors applied in a stack, as it assumes that all values have already been set on the action.

This interceptor does nothing if the name of the method being invoked is specified in the excludeMethods parameter. excludeMethods accepts a comma-delimited list of method names. For example, requests to foo!input.action and foo!back.action will be skipped by this interceptor if you set the excludeMethods parameter to "input, back".

The workflow of the action request does not change due to this interceptor. Rather, this interceptor is often used in conjuction with the workflow interceptor.

NOTE: As this method extends off MethodFilterInterceptor, it is capable of deciding if it is applicable only to selective methods in the action class. See MethodFilterInterceptor for more info.

Parameters

  • alwaysInvokeValidate - Defaults to true. If true validate() method will always be invoked, otherwise it will not.
  • programmatic - Defaults to true. If true and the action is Validateable call validate(), and any method that starts with "validate".
  • declarative - Defaults to true. Perform validation based on xml or annotations.

Extending the Interceptor

There are no known extension points for this interceptor.

Examples

<action name="someAction" class="com.examples.SomeAction">
    <interceptor-ref name="params"/>
    <interceptor-ref name="validation"/>
    <interceptor-ref name="workflow"/>
    <result name="success">good_result.ftl</result>
</action>

<-- in the following case myMethod of the action class will not
       get validated -->
<action name="someAction" class="com.examples.SomeAction">
    <interceptor-ref name="params"/>
    <interceptor-ref name="validation">
        <param name="excludeMethods">myMethod</param>
    </interceptor-ref>
    <interceptor-ref name="workflow"/>
    <result name="success">good_result.ftl</result>
</action>

<-- in the following case only annotated methods of the action class will
       be validated -->
<action name="someAction" class="com.examples.SomeAction">
    <interceptor-ref name="params"/>
    <interceptor-ref name="validation">
        <param name="validateAnnotatedMethodOnly">true</param>
    </interceptor-ref>
    <interceptor-ref name="workflow"/>
    <result name="success">good_result.ftl</result>
</action>