This document describes how an incoming request by the browser client is processed inside an adapter. The request contains all the changes of properties that have been made at client side. The following topics are covered:
init()
This method is called only once - when creating the adapter inside a
subsession. Before calling this method, Application Designer makes sure that the adapter
instance is properly registered inside the Application Designer environment. Therefore - for
example - you have access to the session management: use the
findSessionContext() or
findSubSessionContext() method in order to look for
some values inside the init() method. It is not
possible to use the find...SessionContext() methods
inside the constructor of an adapter - since the session is not yet assigned to
the adapter instance.
When navigating between pages (using the
switchToPage() or
openPopupPage() method), the corresponding adapter
objects are only created once. For example, if you navigate from page
"A" to page "B" and back
to page "A", the adapter of page
"A" does not change. The
init() method is only called once - at the time the
adapter is instanciated.
activate(...)
This method is implemented by the Adapter
class already. You only need to overwrite this method if you want to passivate
the state between requests. In this case, you can activate this state inside
your implemented method of your adapter class. If you use the adapter class to
cooperate, for example, with components running in a container of an application server, you should synchronize the
state passivation with the container's
passivation.
reactOnDataTransferStart()
This method is called when the transfer of the changed properties
starts. You can initialize some internal members at this time. If you overwrite
this method, do not forget to include the method of the super-class
(Adapter.reactOnDataTransferStart()) into your method
implementation!
setXxx(), setYyy(), ...
Now, the set methods of the changed properties of the browser client
are transferred. It is very important that your implemented set methods never
cause an exception or an error.
reactOnDataTransferEnd()
This method is called after setting the changed properties. Use this
method to perform operations you always want to execute when processing a
request.
invoke()-Method
If the request has a method call inside, the method is invoked
now.
processAsDefault()
If the request has no method call, this standard method is
called.
reactOnDataCollectionStart()
This method is called when the transfer of adapter properties starts.
Use this method, for example, for performance improvements during the following
get methods, for example, by building temporary objects.
getXxx(),
getYyy()
All get methods of the adapter - including array elements which may
be passed back by - are called.
reactOnDataColletionEnd()
This method is called when data collection is finished. Temporary
objects - which you may have created for performance reasons - can be released
for garbage collection now.
passivate(...)
This method is the counterpart of the activate method.
endProcess()
This method is called inside the adapter if the user decides to
terminate the subsession. For example, in the Application Designer workplace environment, this
method is called whenever the user chooses the close button of a page.
You can deny closing a subsession in your implemented method:
public class ABCAdapter
extends com.softwareag.cis.server.Adapter
{
...
...
public void endProcess()
{
// veto the endProcess in case of unsaved data
if (changedDataNotSaved == true)
{
this.outputMessage("E","Please save data first");
return;
}
// close subsession
super.endProcess();
}
}
If a session is removed from Application Designer - for example, if the user closes the browser or if a system administrator removes the session - the adapter instances are informed in the following way:
destroy()
In your implemented method, clean up all resources bound to your
adapter instance. You cannot deny the destroying of the session - but you can
react.
Error and runtime exceptions occurring during the adapter request processing may be handled centrally inside your adapter. For more details, see Binding between Page and Adapter in the Special Development Topics.
The methods named above are already implemented with default behavior
inside the class com.softwareag.cis.server.Adapter. Pay
attention when overwriting these methods inside your adapter and always include
the super-class's processing into your own implementation. The first statement
inside your implementation should call the super-class method:
public class ABCAdapter
extends com.softwareag.cis.server.Adapter
{
...
...
public void reactOnDataTransferStart()
{
super.reactOnDataTransferStart();
// now own implementation
...
...
}
}