org.apache.struts.actions
public class EventActionDispatcher extends ActionDispatcher
An Action helper class that dispatches to to one of the public methods
that are named in the parameter
attribute of the corresponding
ActionMapping and matches a submission parameter. This is useful for
developers who prefer to use many submit buttons, images, or submit links
on a single form and whose related actions exist in a single Action class.
The method(s) in the associated Action
must have the same
signature (other than method name) of the standard Action.execute method.
To configure the use of this action in your
struts-config.xml
file, create an entry like this:
<action path="/saveSubscription"
type="org.example.SubscriptionAction"
name="subscriptionForm"
scope="request"
input="/subscription.jsp"
parameter="save,back,recalc=recalculate,default=save"/>
where parameter
contains three possible methods and one
default method if nothing matches (such as the user pressing the enter key).
For utility purposes, you can use the key=value
notation to
alias methods so that they are exposed as different form element names, in the
event of a naming conflict or otherwise. In this example, the recalc
button (via a request parameter) will invoke the recalculate
method. The security-minded person may find this feature valuable to
obfuscate and not expose the methods.
The default key is purely optional. If this is not specified
and no parameters match the list of method keys, null
is
returned which means the unspecified
method will be invoked.
The order of the parameters are guaranteed to be iterated in the order specified. If multiple buttons were accidently submitted, the first match in the list will be dispatched.
To implement this dispatch behaviour in an Action
,
class create your custom Action as follows, along with the methods you require
(and optionally "cancelled" and "unspecified" methods):
public class MyCustomAction extends Action { protected ActionDispatcher dispatcher = new EventActionDispatcher(this); public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception { return dispatcher.execute(mapping, form, request, response); } }
Since: Struts 1.2.9
Field Summary | |
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static String | DEFAULT_METHOD_KEY
The method key, if present, to use if other specified method keys
do not match a request parameter. |
static Log | LOG
Commons Logging instance. |
Constructor Summary | |
---|---|
EventActionDispatcher(Action action)
Constructs a new object for the specified action. |
Method Summary | |
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protected String | getMethodName(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response, String parameter)
Returns the method name, given a parameter's value.
|
protected ActionForward | unspecified(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) Dispatches to the target class' |
Parameters: action the action
Parameters: mapping The ActionMapping used to select this instance form The optional ActionForm bean for this request (if
any) request The HTTP request we are processing response The HTTP response we are creating parameter The ActionMapping
parameter's name
Returns: The method's name.
Throws: Exception if an error occurs.
Dispatches to the target class' unspecified
method, if
present, otherwise throws a ServletException. Classes utilizing
EventActionDispatcher
should provide an unspecified
method if they wish to provide behavior different than throwing a
ServletException.
Parameters: mapping The ActionMapping used to select this instance form The optional ActionForm bean for this request (if any) request The non-HTTP request we are processing response The non-HTTP response we are creating
Returns: The forward to which control should be transferred, or
null
if the response has been completed.
Throws: Exception if the application business logic throws an exception.