Special-Purpose Objects for Data Storage and Retrieval

Using Special-Purpose Data Storage Objects

Implementing the EntryAccess Method

12

Each of your mock entry handler frames must supply an

EntryAccess

method

that creates a cached frame containing the mock entry's data, installs the cached
frame in the mock entry, and returns the cached frame. This method is called when
the system attempts to access a cached frame that is not present.

The system passes the mock entry to your

EntryAccess

method when it is

invoked. This method calls the

EntrySetCachedObject

function to install the

cached frame in the mock entry and then returns the cached frame.

The following code fragment provides a simple example of an

EntryAccess

method:

myHandler := {

object: {foo: 'bar},
EntryAccess: func (mockEntry)

begin

// install cached frame
EntrySetCachedObject(mockEntry, object);
// return cached frame
object;

end,

// your additional slots and methods here
...}

Creating a New Mock Entry

12

The

NewMockEntry

global function creates a new mock entry object having a

specified handler and cached frame. Your application can use this method to create
a new mock entry; for example, in response to a mockSoup

:Add()

message.

The handler frame you pass to the

NewMockEntry

function must define an

EntryAccess

method, as described in "Implementing the EntryAccess Method"

on page 12-15. The handler may also contain supporting methods or data used by
the mock entry; for example, it might hold information local to a specific mock
entry or information required to retrieve the mock entry's data.

Depending on your needs, you can create new mock entries with or without their
corresponding cached frames. To create a mock entry with its cached frame already
installed, pass both the handler and the cached frame to this function.

To create a mock entry without a cached frame, pass

nil

as the value of the

parameter to the

NewMockEntry

function. When a slot in the

returned mock entry is accessed, the handler's

EntryAccess

method is invoked

to create the cached entry if it is not present.