Class PrepareInterceptor
- All Implemented Interfaces:
Serializable
,ConditionalInterceptor
,Interceptor
prepare()
on actions which implement
Preparable
. This interceptor is very useful for any situation where
you need to ensure some logic runs before the actual execute method runs.
A typical use of this is to run some logic to load an object from the database so that when parameters are set they can be set on this object. For example, suppose you have a User object with two properties: id and name. Provided that the params interceptor is called twice (once before and once after this interceptor), you can load the User object using the id property, and then when the second params interceptor is called the parameter user.name will be set, as desired, on the actual object loaded from the database. See the example for more info.
Note: Since XWork 2.0.2, this interceptor extends MethodFilterInterceptor
, therefore being
able to deal with excludeMethods / includeMethods parameters. See [Workflow Interceptor]
(class DefaultWorkflowInterceptor
) for documentation and examples on how to use this feature.
Update: Added logic to execute a prepare{MethodName} and conditionally
the a general prepare() Method, depending on the 'alwaysInvokePrepare' parameter/property
which is by default true. This allows us to run some logic based on the method
name we specify in the ActionProxy
. For example, you can specify a
prepareInput() method that will be run before the invocation of the input method.
Interceptor parameters:
- alwaysInvokePrepare - Default to true. If true, prepare will always be invoked, otherwise it will not.
Extending the interceptor:
There are no known extension points to this interceptor.Example code:
<!-- Calls the params interceptor twice, allowing you to pre-load data for the second time parameters are set --> <action name="someAction" class="com.examples.SomeAction"> <interceptor-ref name="params"/> <interceptor-ref name="prepare"/> <interceptor-ref name="basicStack"/> <result name="success">good_result.ftl</result> </action>
- Author:
- Jason Carreira, Philip Luppens, tm_jee
- See Also:
-
Field Summary
Fields inherited from class org.apache.struts2.interceptor.MethodFilterInterceptor
excludeMethods, includeMethods
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptiondoIntercept
(ActionInvocation invocation) Subclasses must override to implement the interceptor logic.void
setAlwaysInvokePrepare
(String alwaysInvokePrepare) Sets if theprepare
method should always be executed.void
setFirstCallPrepareDo
(String firstCallPrepareDo) Sets if theprepareDoXXX
method should be called firstMethods inherited from class org.apache.struts2.interceptor.MethodFilterInterceptor
applyInterceptor, getExcludeMethodsSet, getIncludeMethodsSet, intercept, setExcludeMethods, setIncludeMethods
Methods inherited from class org.apache.struts2.interceptor.AbstractInterceptor
destroy, init, setDisabled, shouldIntercept
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Constructor Details
-
PrepareInterceptor
public PrepareInterceptor()
-
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Method Details
-
setAlwaysInvokePrepare
Sets if theprepare
method should always be executed.Default is true.
- Parameters:
alwaysInvokePrepare
- ifprepare
should always be executed or not.
-
setFirstCallPrepareDo
Sets if theprepareDoXXX
method should be called firstDefault is false for backward compatibility
- Parameters:
firstCallPrepareDo
- ifprepareDoXXX
should be called first
-
doIntercept
Description copied from class:MethodFilterInterceptor
Subclasses must override to implement the interceptor logic.- Specified by:
doIntercept
in classMethodFilterInterceptor
- Parameters:
invocation
- the action invocation- Returns:
- the result of invocation
- Throws:
Exception
- in case of any errors
-