com.ibm.portal.struts.action
Class DispatchAction

java.lang.Object
  Action
      com.ibm.portal.struts.action.StrutsAction
          com.ibm.portal.struts.action.DispatchAction

Direct Known Subclasses:

LookupDispatchAction

public abstract class DispatchAction
extends StrutsAction

This is a Portal friendly version of DispatchAction. The basic difference is the request object is a PortletRequest object and there is no response object.

Derived from the Struts DispatchAction javadoc:

An abstract Action that dispatches to a public method that is named by the request parameter whose name is specified by the parameter property of the corresponding ActionMapping. This Action is useful for developers who prefer to combine many similar actions into a single Action class, in order to simplify their application design.

To configure the use of this action in your struts-config.xml file, create an entry like this:

<action path="/saveSubscription" type="org.apache.struts.actions.DispatchAction" name="subscriptionForm" scope="request" input="/subscription.jsp" parameter="method"/>

which will use the value of the request parameter named "method" to pick the appropriate "execute" method, which must have the same signature (other than method name) of the standard Action.execute method. For example, you might have the following three methods in the same action:

• public ActionForward delete(ActionMapping mapping, ActionForm form, PortletRequest request ) throws Exception
• public ActionForward insert(ActionMapping mapping, ActionForm form, PortletRequest request) throws Exception
• public ActionForward update(ActionMapping mapping, ActionForm form, PortletRequest request) throws Exception

and call one of the methods with a URL like this:

<html:link action="/saveSubscription.do?method=update">

NOTE - All of the other mapping characteristics of this action must be shared by the various handlers. This places some constraints over what types of handlers may reasonably be packaged into the same DispatchAction subclass.

Since:

5.1

Field Summary

protected java.lang.Class	clazz The Class instance of this DispatchAction class.
protected static Log	log Commons Logging instance.
protected static MessageResources	messages The message resources for this package.
protected java.util.HashMap	methods The set of Method objects 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

DispatchAction()
DispatchAction constructor.

Method Summary

protected ActionForward	ActionRequest, ActionResponse, java.lang.String)">dispatchMethod(ActionMapping mapping, ActionForm form, ActionRequest request, ActionResponse response, java.lang.String name) Dispatches to the specified method.
ActionForward	ActionRequest, ActionResponse)">execute(ActionMapping mapping, ActionForm form, ActionRequest request, ActionResponse response) Processes the current request based on the ActionMapping information.
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 ActionForward	unspecified(ActionMapping mapping, ActionForm form, ActionRequest request) Method which is dispatched to when there is no value for specified request parameter included in the request.

Methods inherited from class com.ibm.portal.struts.action.StrutsAction

sendError, sendError

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

clazz

protected java.lang.Class clazz

The Class instance of this DispatchAction class.

log

protected static Log log

Commons Logging instance.

messages

protected static MessageResources messages

The message resources for this package.

methods

protected java.util.HashMap methods

The set of Method objects introspected for this class, keyed by method name. This collection is populated as different methods are called, so that introspection needs to occur only once per method name.

Derived from the Struts DispatchAction javadoc.

types

protected java.lang.Class[] types

The set of argument type classes for the reflected method call. These are the same for all calls, so calculate them only once.

Derived from the Struts DispatchAction javadoc.

Constructor Detail

DispatchAction

public DispatchAction()

DispatchAction constructor.

Method Detail

ActionRequest, ActionResponse)">

execute

public ActionForward execute(ActionMapping mapping,
                             ActionForm form,
                             ActionRequest request,
                             ActionResponse response)
                      throws java.lang.Exception

Processes the current request based on the ActionMapping information. The processing should return an ActionForward, to control the processing. This implementation does not allow the response object to be written to directly, so an ActionForward should be returned. A null return value will stop the request processing, but will not result in the creation of a new IViewCommand

Overrides:

PortletRequest, PortletResponse)">execute in class StrutsAction

Parameters:

mapping - The ActionMapping used to select this instance

form - The optional ActionForm bean for this request (if any)

request - The portlet request being processed

response - The portlet response being processed

Returns:

the action forward for the mapping parameter

Throws:

java.lang.Exception - if an exception occurs

unspecified

protected ActionForward unspecified(ActionMapping mapping,
                                    ActionForm form,
                                    ActionRequest request)
                             throws java.lang.Exception

Method which is dispatched to when there is no value for specified request parameter included in the request. Subclasses of DispatchAction should override this method if they wish to provide default behavior different than producing an HTTP "Bad Request" error.

Derived from the Struts DispatchAction javadoc

Parameters:

mapping - The ActionMapping used to select this instance

form - The optional ActionForm bean for this request (if any)

request - The portlet request being processed

Returns:

the action forward for the unspecified case, can be null

Throws:

java.lang.Exception - if an exception occurs

ActionRequest, ActionResponse, java.lang.String)">

dispatchMethod

protected ActionForward dispatchMethod(ActionMapping mapping,
                                       ActionForm form,
                                       ActionRequest request,
                                       ActionResponse response,
                                       java.lang.String name)
                                throws java.lang.Exception

Dispatches to the specified method.

Parameters:

mapping - The ActionMapping used to select this instance

form - The optional ActionForm bean for this request (if any)

request - The portlet request being processed

name - the dispatch name

Returns:

ActionForward the action forward for the specified name

Throws:

java.lang.Exception - if an exception occurs

getMethod

protected java.lang.reflect.Method getMethod(java.lang.String name)
                                      throws java.lang.NoSuchMethodException

Introspect the current class to identify a method of the specified name that accepts the same parameter types as the execute method does.

Derived from the Struts DispatchAction javadoc.

Parameters:

name - Name of the method to be introspected

Returns:

Method the method object for the specified name

Throws:

java.lang.NoSuchMethodException - if no such method can be found