AggregatedEventHandler

Class Overview

The AggregatedEventHandler class is intended for customization of existing event handlers. By extending this abstract class, a customized event handler can change the way events are processed, extend the definition of existing events, and create new events.

An instance of this class aggregates a "default" event handler. A custom event handler subclass can either handle a given event itself or delegate it to the aggregated default handler.

Custom event handler subclasses must implement the abstract method processRequest, which serves as the entrypoint for event processing. From there, the custom handler can choose to handle a given event itself, or delegate it by calling handleDefaultRequest.

The default event handler is set via the setDefaultHandler method. Typically, it is not necessary for custom event handler implementations to explicitly call this method. By default, when the system creates an AggregatedEventHandler to be associated with a given bean, it will use the bean's event handler as the default handler (see the example below).

The following code shows a custom event handler that can be associated with a FolderBean:

 public class CustomFolderHandler extends AggregatedEventHandler {
     public boolean processRequest(RequestKeys keys) throws WebException {
         int eventID = getEventID(keys);
         switch (eventID) {
             // handle desired events here
         }

         // or delegate to the default handler
         return handleDefaultRequest(keys);
     }
 }
 

To associate this event handler with a bean, update the bean's <web-bean> node in pageConfig.xml.
Typically, the line in pageConfig.xml that specifies a given bean looks like:

   <web-bean name="fb" persist-mode="2" sys-bean="FolderBean"/>
 

We use the event-handler attribute to associate a custom event handler with that bean:

   <web-bean name="fb" persist-mode="2" sys-bean="FolderBean" event-handler="com.xyz.CustomFolderHandler"/>
 

where com.xyz.CustomFolderHandler is the fully qualified class name of the custom event handler class.

At runtime, when the bean shown above needs to be created, the system will first instantiate a new FolderBean instance. It will then create a new CustomFolderHandler instance that aggregates the FolderBean instance's event handler. Finally, it will call WebComponent.setWebEventHandler to associate the CustomFolderHandler instance with the FolderBean instance.

Summary

[Expand] Inherited Constants
From class com.microstrategy.web.beans.GenericEventHandler String MULTIPLE_EVENT_SOURCE_SUFFIX int NO_EVENT_ID This constant represents the ID returned by the getEventID method when there is no event in the request
From interface com.microstrategy.web.beans.WebEventTags String ATT_ARGUMENT_ENUMERATOR The enumeration value for event argument id. String ATT_ARGUMENT_ID The id attribute of the XML tag event argument String ATT_ARGUMENT_INDEX The index attribute of the XML tag event argument String ATT_ARGUMENT_NAME The name attribute of the XML tag event argument String ATT_ARGUMENT_REQUIRED The required attribute of the XML tag event argument String ATT_ARGUMENT_TYPE The type attribute of the XML tag event argument String ATT_ARGUMENT_VALIDATOR The validator attribute of the XML tag event argument String ATT_ARGUMENT_VALUE The value attribute of the XML tag event argument String ATT_EVENT_DEPRECATED Attribute marking the event as deprecated. String ATT_EVENT_ENUMERATOR The enumeration value for event id. String ATT_EVENT_HANDLER_ENUMERATOR The enumeration value for event handler type. String ATT_EVENT_HANDLER_NAME The name attribute of the XML tag eventHandler String ATT_EVENT_HANDLER_TYPE The type attribute of the XML tag eventHandler String ATT_EVENT_ID The id attribute of the XML tag event String ATT_EVENT_NAME The name attribute of the XML tag event String ATT_EVENT_TARGET The name attribute of the XML tag event String TAG_ARGUMENT The XML tags for event argument String TAG_ARGUMENTS The XML tags for event arguments String TAG_EVENT The XML tags for event String TAG_EVENTS The XML tags for events String TAG_EVENT_HANDLER The XML tags for event_handler String TAG_EVENT_HANDLERS The XML tags for event_handlers

Fields
protected WebEventHandler	defaultHandler	The default event handler.

[Expand] Inherited Fields
From class com.microstrategy.web.beans.GenericEventHandler protected List<WebEvent> _extraEvents protected int layerOfHandleRequest

Protected Constructors
	AggregatedEventHandler(int type) This constructor is deprecated. Use the no-arg constructor, along with setDefaultHandler if necessary. For flexibilty reasons, this class should no longer be responsible for creating the default handler based on its type.
	AggregatedEventHandler() Constructs an AggregatedEventHandler without a default handler.

Public Methods
boolean	delegateRequest(RequestKeys keys) The default implementation of this method simply delegates the event to the next source component specified in the static field GenericWebEvent.URL_SOURCE_NAME.
WebEventHandler	getDefaultHandler() Returns the default event handler.
int	getHandlerType() Returns the event handler type.
Class	getSupportedWebComponentType() Returns the Class type of the WebComponent this event handler is associated with.
WebEvent	getWebEvent(int id) Returns the specified WebEvent instance which this event handler supports.
abstract boolean	processRequest(RequestKeys keys) This method encapsulates the logic to process an incoming event.
void	setDefaultHandler(WebEventHandler handler) Sets the default event handler.

Protected Methods
boolean	defaultDelegate(RequestKeys keys)
boolean	handleDefaultRequest(RequestKeys keys) Asks the default event handler to handle the request.
void	setHandlerType(int type) Sets the event handler type.

[Expand] Inherited Methods
From class com.microstrategy.web.beans.GenericEventHandler void addEvent(WebEvent event) Adds a WebEvent instance into the current event handler. void addEvent(Element eventNode) This method is deprecated. The GenericEventHandler is not responsible to read the xml structure, therefore this method is not used anymore. Events should be added to an event handler using the Web Customization Editor void addEvents(Element node) This method is deprecated. The GenericEventHandler is not responsible to read the xml structure, therefore this method is not used anymore. Events should be added to an event handler using the Web Customization Editor void addEventsFromXML(String eventsXML) This method is deprecated. The GenericEventHandler is not responsible to read the xml structure, therefore this method is not used anymore. Events should be added to an event handler using the Web Customization Editor void appendRemainingEvent(WebEvent event) Append an remaining event at the end of the remaining events' list. Object clone() Clone the current event handler instance. boolean delegateRequest(RequestKeys keys) The default implementation of this method simply delegates the event to the next source component specified in the static field GenericWebEvent.URL_SOURCE_NAME. static int getEventID(RequestKeys keys) Retrieves the event id passed in from the RequestKeys. WebComponent getEventTarget(RequestKeys keys) int getHandlerType() Returns the type of the current WebEventHandle. String getName() Returns the name of this event handler String getNextSourceName(RequestKeys keys) Returns the next component name in the event component path. static String getNextSourceName(String currentBeanPath, String eventFullPath) Returns the next source component which will handle the event. SimpleList getPendingEvents() Returns the list of events that were not processed. Class getSupportedWebComponentType() Returns the WebComponent class by default. WebComponent getWebComponent() Returns the WebComponent object associated with the current event handler. WebEvent getWebEvent(int eventID, RequestKeys keys) This method should be used when the eventID passed in is different from the one that is included as a value in the keys parameter WebEvent getWebEvent(RequestKeys keys) Decodes the WebEvent from the RequestKeys. WebEvent getWebEvent(int eventID) Returns the specified WebEvent instance which this event handler supports. Enumeration getWebEvents() Returns an enumeration over the WebEvent suppored by this event handler. Enumeration getWebEventsFromRequest(RequestKeys keys) Returns an enumeration over the WebEvent suppored by this event handler that are present in the request keys provided. boolean handleRequest(RequestKeys keys) Handles the WebEvent specified in the RequestKeys object. boolean isInitialized() Returns true after the markInitailized() has been called. boolean isMyEvent(RequestKeys keys) void markInitailized() Call this method to mark this event-handler instance as initialized. void processExtraEvents() static void processMultipleEvents(String flatState, MultipleEventHandler handler) This method is deprecated. Use processMultipleEvents(String, MultipleEventHandler, String) static void processMultipleEvents(String flatState, MultipleEventHandler handler, String componentPath) Processes multiple events encoded via the FlatStateSerializer. boolean processRequest(RequestKeys keys) Logic to process the event. void setHandlerType(int type) Sets the type of the current event handler. void setName(String name) Sets the name to this event handler void setWebComponent(WebComponent component) Sets a WebComponent instance on this event handler. void validateRequiredArgument(String argName, String argValue) A helper method which ensures that the argValue corresponding to argName is not null and not empty.
From class java.lang.Object Object clone() boolean equals(Object arg0) void finalize() final Class<?> getClass() int hashCode() final void notify() final void notifyAll() String toString() final void wait() final void wait(long arg0, int arg1) final void wait(long arg0)
From interface com.microstrategy.web.beans.WebEventHandler abstract void addEvent(WebEvent event) Adds WebEvent into the current event handler. abstract void addEventsFromXML(String eventsXML) Adds one or more WebEvent into the current event handler. abstract void appendRemainingEvent(WebEvent event) Append an remaining event at the end of the remaining events' list. abstract boolean delegateRequest(RequestKeys keys) This method encapsulates the mechanism by which a request is delegated to child WebComponents. abstract int getHandlerType() Returns the type of the current WebEventHandle. abstract SimpleList getPendingEvents() Returns the list of events that were not processed. abstract Class getSupportedWebComponentType() Returns the Class type of the WebComponent this event handler is associated with. abstract WebComponent getWebComponent() Returns the WebComponent object associated with the current event handler. abstract WebEvent getWebEvent(int eventID) Returns the specified WebEvent instance which this event handler supports. abstract Enumeration getWebEvents() Returns an enumeration over the WebEvent objects suppored by this event handler. abstract Enumeration getWebEventsFromRequest(RequestKeys keys) Returns an enumeration over the WebEvent suppored by this event handler that are present in the request keys provided. abstract boolean handleRequest(RequestKeys keys) Handles the WebEvent specified in the RequestKeys object. abstract boolean processRequest(RequestKeys keys) This method encapsulates the logic to process incoming events without regard as to how it was triggered or be concerned with delegation the request (see processRequest(RequestKeys)). abstract void setWebComponent(WebComponent component) Sets a WebComponent instance on this WebEventHandler.