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java.lang.Object | +--org.apache.struts.actions.ActionDispatcher
Action helper class that dispatches to a public method in an Action.
This class is provided as an alternative mechanism to using DispatchAction
and its various flavours and means Dispatch behaviour can be
easily implemented into any Action
without having to
inherit from a particular super Action
.
To implement 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 ActionDispatcher(this, ActionDispatcher.MAPPING_FLAVOR); public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception { return dispatcher.execute(mapping, form, request, response); } }
It provides three flavours of determing the name of the method:
DEFAULT_FLAVOR
- uses the parameter specified in
the struts-config.xml to get the method name from the Request
(equivalent to DispatchAction
except uses "method"
as a default if the parameter
is not specified
in the struts-config.xml).DISPATCH_FLAVOR
- uses the parameter specified in
the struts-config.xml to get the method name from the Request
(equivalent to DispatchAction
).MAPPING_FLAVOR
- uses the parameter specified in
the struts-config.xml as the method name
(equivalent to MappingDispatchAction
).
Field Summary | |
protected Action |
actionInstance
The associated Action to dispatch to. |
protected java.lang.Class |
clazz
The Class instance of this DispatchAction class. |
static int |
DEFAULT_FLAVOR
Indicates "default" dispatch flavor |
static int |
DISPATCH_FLAVOR
Indicates flavor compatible with DispatchAction |
protected int |
flavor
Indicates dispatch flavor |
protected static org.apache.commons.logging.Log |
log
Commons Logging instance. |
static int |
MAPPING_FLAVOR
Indicates "mapping" dispatch flavor |
protected static MessageResources |
messages
The message resources for this package. |
protected java.util.HashMap |
methods
The set of Method objects we have introspected for this class, keyed by method name. |
protected java.lang.Class[] |
types
The set of argument type classes for the reflected method call. |
Constructor Summary | |
ActionDispatcher(Action actionInstance)
|
|
ActionDispatcher(Action actionInstance,
int flavor)
|
Method Summary | |
protected ActionForward |
cancelled(ActionMapping mapping,
ActionForm form,
javax.servlet.http.HttpServletRequest request,
javax.servlet.http.HttpServletResponse response)
Dispatches to the target class' cancelled method, if present, otherwise returns null. |
protected ActionForward |
dispatchMethod(ActionMapping mapping,
ActionForm form,
javax.servlet.http.HttpServletRequest request,
javax.servlet.http.HttpServletResponse response,
java.lang.String name)
Dispatch to the specified method. |
protected ActionForward |
dispatchMethod(ActionMapping mapping,
ActionForm form,
javax.servlet.http.HttpServletRequest request,
javax.servlet.http.HttpServletResponse response,
java.lang.String name,
java.lang.reflect.Method method)
Dispatch to the specified method. |
ActionForward |
execute(ActionMapping mapping,
ActionForm form,
javax.servlet.http.HttpServletRequest request,
javax.servlet.http.HttpServletResponse response)
Process the specified HTTP request, and create the corresponding HTTP response (or forward to another web component that will create it). |
protected java.lang.reflect.Method |
getMethod(java.lang.String name)
Introspect the current class to identify a method of the specified name that accepts the same parameter types as the execute
method does. |
protected java.lang.String |
getMethodName(ActionMapping mapping,
ActionForm form,
javax.servlet.http.HttpServletRequest request,
javax.servlet.http.HttpServletResponse response,
java.lang.String parameter)
Returns the method name, given a parameter's value. |
protected java.lang.String |
getParameter(ActionMapping mapping,
ActionForm form,
javax.servlet.http.HttpServletRequest request,
javax.servlet.http.HttpServletResponse response)
Returns the parameter value as influenced by the selected flavor specified for this ActionDispatcher . |
protected boolean |
isCancelled(javax.servlet.http.HttpServletRequest request)
Returns true if the current form's cancel button was
pressed. |
protected ActionForward |
unspecified(ActionMapping mapping,
ActionForm form,
javax.servlet.http.HttpServletRequest request,
javax.servlet.http.HttpServletResponse response)
Dispatches to the target class' unspecified method,
if present, otherwise throws a ServletException. |
Methods inherited from class java.lang.Object |
|
Field Detail |
public static final int DEFAULT_FLAVOR
public static final int MAPPING_FLAVOR
public static final int DISPATCH_FLAVOR
protected Action actionInstance
protected int flavor
protected java.lang.Class clazz
DispatchAction
class.protected static org.apache.commons.logging.Log log
protected static MessageResources messages
protected java.util.HashMap methods
protected java.lang.Class[] types
Constructor Detail |
public ActionDispatcher(Action actionInstance)
public ActionDispatcher(Action actionInstance, int flavor)
Method Detail |
public ActionForward execute(ActionMapping mapping, ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws java.lang.Exception
ActionForward
instance describing where and how
control should be forwarded, or null
if the response has
already been completed.mapping
- The ActionMapping used to select this instanceform
- The optional ActionForm bean for this request (if any)request
- The HTTP request we are processingresponse
- The HTTP response we are creatingjava.lang.Exception
- if an exception occursprotected ActionForward unspecified(ActionMapping mapping, ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws java.lang.Exception
Dispatches to the target class' unspecified
method,
if present, otherwise throws a ServletException. Classes utilizing
ActionDispatcher
should provide an unspecified
method if they wish to provide behavior different than
throwing a ServletException..
protected ActionForward cancelled(ActionMapping mapping, ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws java.lang.Exception
Dispatches to the target class' cancelled method, if present,
otherwise returns null. Classes utilizing ActionDispatcher
should provide a cancelled
method if they wish to provide
behavior different than returning null.
protected ActionForward dispatchMethod(ActionMapping mapping, ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, java.lang.String name) throws java.lang.Exception
protected ActionForward dispatchMethod(ActionMapping mapping, ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, java.lang.String name, java.lang.reflect.Method method) throws java.lang.Exception
protected java.lang.reflect.Method getMethod(java.lang.String name) throws java.lang.NoSuchMethodException
execute
method does.name
- Name of the method to be introspectedjava.lang.NoSuchMethodException
- if no such method can be foundprotected java.lang.String getParameter(ActionMapping mapping, ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) throws java.lang.Exception
Returns the parameter value as influenced by the selected
flavor
specified for this ActionDispatcher
.
mapping
- The ActionMapping used to select this instanceform
- The optional ActionForm bean for this request (if any)request
- The HTTP request we are processingresponse
- The HTTP response we are creatingActionMapping
parameter's valueprotected java.lang.String getMethodName(ActionMapping mapping, ActionForm form, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, java.lang.String parameter) throws java.lang.Exception
mapping
- The ActionMapping used to select this instanceform
- The optional ActionForm bean for this request (if any)request
- The HTTP request we are processingresponse
- The HTTP response we are creatingparameter
- The ActionMapping
parameter's nameprotected boolean isCancelled(javax.servlet.http.HttpServletRequest request)
Returns true
if the current form's cancel button was
pressed. This method will check if the Globals.CANCEL_KEY
request attribute has been set, which normally occurs if the cancel
button generated by CancelTag was pressed by the user
in the current request. If true
, validation performed
by an ActionForm's validate()
method
will have been skipped by the controller servlet.
request
- The servlet request we are processingCancelTag
|
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