Enhanced Guide to Oracle8i
Chapter 12:
Form Builder Objects
and Flexible Code
1
Object-Oriented Principles

Object


Class


Group of objects with the same structure and
properties
Class instance


Abstract representation of something in the real
world
Object that belongs to a specific class
Inheritance

Specifies that when you create a new object, it
inherits its structure and properties from its class
2
Subclasses


Classes that have similar properties and
structure of their parent class
Subclasses have specializations, which
are properties that make them different
than their parent class
3
Form Builder Approaches For
Creating Reusable Objects




Property Classes
Object Groups
Object Libraries
PL/SQL Libraries
4
Property Classes


Top-level Form
Builder objects
that specify a
collection of
properties with
specific values
Property classes
can be associated
with Form Builder
objects to define
object properties
5
Creating a Property Class

Approaches:


Create the property class based on an
existing object
Explicitly create the property class object,
and then define its properties and
associated values
6
Creating a Property Class
Based on an Existing Object


Create the object and
configure its
properties as desired
In the object’s
Property Palette,
select the desired
properties and then
click the Property
Class button
on
the toolbar to create
the property class
7
Creating a Property Class
Explicitly



Create the property class object in the
Object Navigator and open its Property
Palette
To add a property, click the Add
Property button
To remove a property, select the
property and then click the Remove
Property button
8
Using Property Classes to
Subclass Form Objects


When you apply a property class to a
form object, the form object is
subclassed to the property class
To subclass a form object, open the
object’s Property Palette, and the the
property class name in the Subclass
Information dialog box
9
Using the Subclass
Information Dialog box


Select whether
you are
subclassing from
an object or a
property class
Select the
property class
name
10
Object Groups


Top-level form objects that contain groups of
objects that can be reused in different forms
Examples of object types in object groups:




LOVs
Data blocks
Alerts
Object groups are created in a source from,
and then subclassed into target forms
11
Creating an Object Group


Create a new
object group
object in the
form template
Rename the
object group
12
Adding Objects to an Object
Group


Create the objects
Drag and drop the
objects on the
object group
Object Group
Children node
13
Subclassing Object Groups in
Target Forms


Select the object group in the source
form
Drag the object group to the Object
Groups node in the target form, drop
the object group, and click the Subclass
button
14
Subclassing vs.
Copying Objects


When you subclass an object, changes
to original object are propagated to
subclassed objects
When you copy an object, changes to
original object do not affect subclassed
objects
15
Form With Objects Subclassed
From Object Group
Subclassed
objects
Subclassed
object group
16
Object Libraries


Top-level Form
Builder objects that
are independent of
specific forms
Contain form
objects that can be
referenced in
specific forms
17
Creating an Object Library


Create a new object library object in
Form Builder
Save the object library file


File has an .olb extension
Filename specifies object library name
18
Object Library Structure

Consists of multiple library tabs

Tab pages that contain one or more similar
object instances
19
Creating and Configuring Tab
Pages



To create a new tab
page, select the Library
Tabs node, and then
click the Create button
Right-click the new tab
page, and then click
Property Palette to
open the tab page
Property Palette
Change the tab page
Name and Label values
20
Opening the Object Library

Double-click the object library icon
to open the Object Library window
Library tabs
Object on
tab page
21
Adding Form Objects to
Library Tab Pages


Create and configure the object in a source
form
Open the source form Object Navigator and
the Object Library window side-by-side




Maximize the Object Navigator window
Open the Object Library window, and then click
the Restore button
so the Object Library
appears in a window
Reposition the windows as necessary
Drag and drop the object onto the Library Tab
page
22
Window Configuration For
Adding Objects
Object Navigator
window
Object
Library window
Object
to be
stored in
library
23
Using Object Library Objects
in Forms



Open the target form Object Navigator
and the Object Library window side-byside
Drag and drop the object library object
into the target form
Subclass the object into the target form
24
SmartClasses



Object library objects that are defined as
standard object types for an application
SmartClassed objects appear as selections on
a pop-up menu when you create a new
object and then right-click the object
Speeds up the process of using object
libraries
25
Creating a SmartClass


Select the object in the object library
Click Object on the menu bar, and then
click SmartClass
Green check
indicates object
is a SmartClass
26
Selecting a SmartClass
27
PL/SQL Libraries



Library of PL/SQL named program units that
can be used in forms
Top-level Form Builder object that is not
associated with a specific form
Specific program units can be attached to
forms


Code is not part of form .fmb file
Code is only loaded when program unit is called
28
Creating a PL/SQL Library in
Form Builder


Select the PL/SQL
Libraries node, and
then click the
Create button
Save the library in
the file system


Library name is the
same as the
filename
File has a .pll
extension
29
Saving PL/SQL Library Files

In general, PL/SQL library files should
be saved in the default PL/SQL library
folder


Path: Developer_Home\TOOLS\OPEN60
If you save a library file in a different
location, that path and file must always
be available when you open forms that
reference the library
30
Adding Program Units to
PL/SQL Libraries



Select the library Program Units node,
and then click the Create button
Select the named program unit type
(procedure, function, package)
Type the program unit code in the
PL/SQL Editor window
31
Using PL/SQL Libraries in
Forms


Attach the library to the form
Call the library program units from form
triggers
32
Attaching a PL/SQL Library to
a Form


Select the form’s Attached Libraries
node, and then click the Create button
Navigate to the library file and attach
the file


If the library is saved in the default library
folder, click Yes to discard path information
If the library is not saved in the default
library folder, click No to save path
information
33
Calling a Library Program Unit
From a Form Trigger

Reference the program unit and pass
the required parameters as specified in
the attached library specification in the
Object Navigator
34
Calendar Windows



Associated with a
form text item that
displays date values
Allows the user to
select a date
The selected date
value is returned to
the form text item
35
Creating a Calendar Window



Open the STNDRD20.OLB object library
and copy or subclass the Calendar
object group into the form
Attach the CALENDAR.PLL PL/SQL
library to the form
Create a trigger associated with the
form text item that calls a procedure in
the CALENDAR.PLL PL/SQL library
36
Subclassing the Calendar
Object Group Into the Form



Open the target form
Open the STNDRD20.OLB object library
Subclass the CALENDAR object group
into the target form
37
Subclassing the Calendar
Object Group Into the Form
38
Attaching the CALENDAR.PLL
PL/SQL Library to the Form


Create a new
attached library
object in the target
form
Click Browser, select
CALENDAR.PLL, click
Open, and then click
Attach to attach the
library
39
Creating a Trigger to Open the
Calendar Window


Create a Show Calendar button
next to the date text item
Create the trigger to call the GET_DATE
procedure in the DATE_LOV package
40
Creating a Trigger to Open the
Calendar Window
41
Flexible Code


Allows you to create objects that can be
configured at runtime
Approaches


Use system variables to retrieve and set
system values
Use built-in subprograms that dynamically
retrieve and set form object properties
42
Using Built-in Subprograms to
Create Flexible Code

GET_ built-ins


Allow you to retrieve current object
properties
SET_ built-ins

Allow you to dynamically set object
properties
43
GET_APPLICATION_PROPERTY
Built-in


Returns information about the current
Form Builder application
Syntax:
GET_APPLICATION_PROPERTY(property_name);
44
Retrieving Specific Object
Properties

Syntax:
return_value := GET_object_PROPERTY
(object_id | ‘object_name’,
property_name);
45
Retrieving Object ID Values
Using the FIND_ Built-ins

Syntax:
return_value :=
FIND_object(‘object_name’);
46
Dynamically Setting Object
Properties

Syntax:
SET_object_PROPERTY(object_id |
‘object_name’, property_name,
property_value);
47
Using Indirect Referencing to
Write Flexible Code

Direct referencing


Directly referencing a form object using the
format :block_name.object_name
Indirect referencing


Specifying block and item names in single
quotation marks
Allows you to reference objects that are
not in the current form
48
Commands For Indirect
Referencing

COPY


Indirectly sets the value of a form item
Syntax:
COPY(value, ‘destination’);
 Value: desired value
 Destination: form item
 Format: block_name.item_name
49
Commands For Indirect
Referencing

NAME_IN


Indirectly retrieves the value of a form item
Syntax:
return_value := NAME_IN(source);
 Return_value: retrieved value
 Is always a character string
 Source: form item
 Format: block_name.item_name
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