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Interceptor	Name	Description
Alias Interceptor	alias	Converts similar parameters that may be named differently between requests.
Chaining Interceptor	chain	Makes the previous Action's properties available to the current Action. Commonly used together with <result type="chain"> (in the previous Action).
Checkbox Interceptor	checkbox	Adds automatic checkbox handling code that detect an unchecked checkbox and add it as a parameter with a default (usually 'false') value. Uses a specially named hidden field to detect unsubmitted checkboxes. The default unchecked value is overridable for non-boolean value'd checkboxes.
Cookie Interceptor	cookie	Inject cookie with a certain configurable name / value into action. (Since 2.0.7.)
Conversion Error Interceptor	conversionError	Adds conversion errors from the ActionContext to the Action's field errors
Create Session Interceptor	createSession	Create an HttpSession automatically, useful with certain Interceptors that require a HttpSession to work properly (like the TokenInterceptor)
DebuggingInterceptor	debugging	Provides several different debugging screens to provide insight into the data behind the page.
Execute and Wait Interceptor	execAndWait	Executes the Action in the background and then sends the user off to an intermediate waiting page.
Exception Interceptor	exception	Maps exceptions to a result.
File Upload Interceptor	fileUpload	An Interceptor that adds easy access to file upload support.
I18n Interceptor	i18n	Remembers the locale selected for a user's session.
Logger Interceptor	logger	Outputs the name of the Action.
Message Store Interceptor	store	Store and retrieve action messages / errors / field errors for action that implements ValidationAware interface into session.
Model Driven Interceptor	modelDriven	If the Action implements ModelDriven, pushes the `getModel` Result onto the Value Stack.
Scoped Model Driven Interceptor	scopedModelDriven	If the Action implements ScopedModelDriven, the interceptor retrieves and stores the model from a scope and sets it on the action calling `setModel`.
Parameters Interceptor	params	Sets the request parameters onto the Action.
Prepare Interceptor	prepare	If the Action implements Preparable, calls its `prepare` method.
Scope Interceptor	scope	Simple mechanism for storing Action state in the session or application scope.
Servlet Config Interceptor	servletConfig	Provide access to Maps representing HttpServletRequest and HttpServletResponse.
Static Parameters Interceptor	staticParams	Sets the `struts.xml` defined parameters onto the action. These are the <param> tags that are direct children of the <action> tag.
Roles Interceptor	roles	Action will only be executed if the user has the correct JAAS role.
Timer Interceptor	timer	Outputs how long the Action takes to execute (including nested Interceptors and View)
Token Interceptor	token	Checks for valid token presence in Action, prevents duplicate form submission.
Token Session Interceptor	tokenSession	Same as Token Interceptor, but stores the submitted data in session when handed an invalid token
Validation Interceptor	validation	Performs validation using the validators defined in action-validation.xml
Workflow Interceptor	workflow	Calls the `validate` method in your Action class. If Action errors are created then it returns the `INPUT` view.
Parameter Filter Interceptor	N/A	Removes parameters from the list of those available to Actions
Profiling Interceptor	profiling	Activate profiling through parameter
Multiselect Interceptor	multiselect	Like the checkbox interceptor detects that no value was selected for a field with multiple values (like a select) and adds an empty parameter

Warning
Since 2.0.7, Interceptors and Results with hyphenated names were converted to camelCase. (The former model-driven is now modelDriven.) The original hyphenated names are retained as "aliases" until Struts 2.1.0. For clarity, the hyphenated versions are not listed here, but might be referenced in prior versions of the documentation.

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Interceptor Parameter Overriding

Wiki Markup
{snippet:id=parameterOverriding\|javadoc=true\|url=com.opensymphony.xwork2.interceptor/Interceptor.java}

Interceptor Parameter Overriding Inheritance

Parameters override are not inherited in interceptors, meaning that the last set of overridden parameters will be used. For example, if a stack overrides the parameter "defaultBlock" for the "postPrepareParameterFilter" interceptor as:

Interceptor's parameter could be overriden through the following ways :

Method 1:

Code Block

	xml
	xml


<action name="myAction" class="myActionClass">
    <interceptor-ref name="exception"/>
    <interceptor-ref name="alias"/>
    <interceptor-ref name="params"/>
    <interceptor-ref name="servletConfig"/>
    <interceptor-ref name="prepare"/>
    <interceptor-ref name="i18n"/>
    <interceptor-ref name="chain"/>
    <interceptor-ref name="modelDriven"/>
    <interceptor-ref name="fileUpload"/>
    <interceptor-ref name="staticParams"/>
    <interceptor-ref name="params"/>
    <interceptor-ref name="conversionError"/>
    <interceptor-ref name="validation">
    <param name="excludeMethods">myValidationExcudeMethod</param>
    </interceptor-ref>
    <interceptor-ref name="workflow">
    <param name="excludeMethods">myWorkflowExcludeMethod</param>
    </interceptor-ref>
</action>

Method 2:
{code:xml}
<action name="myAction" class="myActionClass">
  <interceptor-ref name="defaultStack">
    <param name="validation.excludeMethods">myValidationExcludeMethod</param>
    <param name="workflow.excludeMethods">myWorkflowExcludeMethod</param>
  </interceptor-ref>
</action>

In the first method, the whole default stack is copied and the parameter then changed accordingly.

In the second method, the interceptor-ref refers to an existing interceptor-stack, namely defaultStack in this example, and override the validator and workflow interceptor excludeMethods attribute. Note that in the param tag, the name attribute contains a dot (.) the word before the dot(.) specifies the interceptor name whose parameter is to be overridden and the word after the dot (.) specifies the parameter itself. The syntax is as follows:

Code Block
<interceptor-name>.<parameter-name>

Note also that in this case the interceptor-ref name attribute is used to indicate an interceptor stack which makes sense as if it is referring to the interceptor itself it would be just using Method 1 describe above.

Code Block



h3. Interceptor Parameter Overriding Inheritance

Parameters override are not inherited in interceptors, meaning that the last set of overridden parameters will be used. For example, if a stack overrides the parameter "defaultBlock" for the "postPrepareParameterFilter" interceptor as:
{code:xml}

Code Block

xml

<interceptor-stack name="parentStack">
  <interceptor-ref name="postPrepareParameterFilter">
    <param name="defaultBlock">true</param>
  </interceptor-ref>
</interceptor-stack>

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Interceptors provide an excellent means to wrap before/after processing. The concept reduces code duplication (think AOP).

Code Block

	xml
	xml

<interceptor-stack name="xaStack">
  <interceptor-ref name="thisWillRunFirstInterceptor"/>
  <interceptor-ref name="thisWillRunNextInterceptor"/>
  <interceptor-ref name="followedByThisInterceptor"/>
  <interceptor-ref name="thisWillRunLastInterceptor"/>
</interceptor-stack>

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Interceptor Parameter Overriding

Interceptor Parameter Overriding Inheritance