"Extending the Workplace Shell with Object REXX"

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"Extending the Workplace Shell with Object REXX"

Page 1

Abteilung für

Wirtschaftsinformatik

"Extending the Workplace Shell with

Object REXX"

Keywords: SOM, WPS, Object Rexx

Rony G. Flatscher

(Rony.Flatscher@wu-wien.ac.at)

Vienna University of Economics and

Business Administration (Wirtschaftsuniversität Wien)

(http://www.wu-wien.ac.at

)

IS Department

(http://www.wu-wien.ac.at/wi

)

University of Essen

(http://www.Uni-Essen.de

)

IS Department

(http://nestroy.wi-inf.Uni-Essen.de

)

(Object Rexx: Extending the WPS ...), page 1

Page 2

IBM "System Object Model" (SOM)

SOM 1.x, SOM 2.1, SOM 3.0

Brief intro and overview

IBM "Workplace Shell" (WPS)

Brief intro and overview

Object Rexx (ORX)

"switchRx"

Interface to SOM

Example: Querying the SOM Interface Repository

Interface to WPS

"wpsinst +"

Example: Creating a password protected WPS folder

Example: Querying the active workplace shell

Overview

(Object Rexx: Extending the WPS ...), page 2

Page 3

Object-oriented run-time system

OO-shaped interface for programs

COBOL (!)

C++

Object Rexx ...

Instead of n! interfaces between all programming

languages only n needed:

per language one interface to SOM

interface definitions

define methods (functions) and their signatures

define attributes

define type of arguments: IN, OUT, INOUT

Knowledge used for shaping OMG's CORBA standard

System Object Model (SOM, 1)

(Object Rexx: Extending the WPS ...), page 3

Page 4

Object-oriented run-time system

SOM 1.0

introduced with OS/2 2.0 (1992!)

single process

WPS built on it

SOM 2.x

introduced with OS/2 3.0

multiple processes: OMG CORBA 1.1 compliant ORB

distributable: DSOM

available also for AIX, Windows/NT

SOM 3.0

December 1996

fully CORBA 2.0 compliant (inter-ORB)

unsupported (!) but freely downloadable for OS/2, AIX,

Windows/NT from IBM's websites

System Object Model (SOM, 2)

(Object Rexx: Extending the WPS ...), page 4

Page 5

Class hierarchy

root: class "SOMObject"

e.g. methods "somInit", "somUninit", "somGetClass",

"somIsA"

metaclass: class "SOMClass"

e.g. methods "somNew", "somGetName", "somFindMethod"

SOM Frameworks

Interface Repository

Metaclass Management

Event Management

System Object Model (SOM, 3)

(Object Rexx: Extending the WPS ...), page 5

Page 6

Workplace Shell (WPS, 1)

Object-oriented user interface

introduced with OS/2 2.0 (1992!)

extensible framework

built with SOM technology

each WPS class is in effect a SOM class

hence, at least all SOM methods of SOM's root class "SOMObject"

are available

all WPS classes are retrievable via the SOM runtime, which

manages all SOM classes

Rexx-interface via Rexx Utility Functions

SysCreateObject, SysDestroyObject, SysSetObjectData,

SysSetIconData, SysRegisterObjectClass,

SysDeregisterObjectClass, SysQueryClassList,

SysGetEa, SysPutEa, SysIni

(Object Rexx: Extending the WPS ...), page 6

Page 7

Workplace Shell (WPS, 2)

Class hierarchy

root: class "WPObject"

a specialization (direct subclass) of class "SOMObject"

all "SOMObject" methods are available to all WPS-classes via

inheritance

e.g. methods

"wpOpen", "wpClose", "wpDelete", "wpCopyObject",

"wpSaveState", "wpRestoreState" etc.

superclass of

"WPAbstract", "WPFileSystem", "WPTransient"

(Object Rexx: Extending the WPS ...), page 7

Page 8

Workplace Shell (WPS, 3)

Class hierarchy (continued)

class "WPAbstract"

not reflected in the file system as files

data stored in INI-files

superclass of

e.g. "WPClock", "WPKeyboard", "WPMouse", "WPPalette",

"WPProgram", "WPShadow", "WPSound" etc.

class "WPFileSystem"

classes which are reflected in the file system as files

data stored in files

superclass of

"WPDataFile" (superclass of e.g. "WPHtml", "WPPointer")

"WPFolder" (superclass of e.g. WPDesktop", "WPDrives",

"WPNetwork", "WPStartup", "WPTemplates")

(Object Rexx: Extending the WPS ...), page 8

Page 9

Workplace Shell (WPS, 4)

Class hierarchy (continued)

class "WPTransient"

classes which just exist during an operating system run

i.e. lifecycle starts with "Startup" and ends with "Shutdown"

storage of data usually not necessary

superclass of

"WPJob", "WPDevice" (e.g. "WPDevSerial", "WPDevAudio"),

"WPPort", "WPPdr", "WPQdr"

(Object Rexx: Extending the WPS ...), page 9

Page 10

Object Rexx and SOM (ORX, 1)

Object-oriented version of the great Rexx-Interpreter

Introduced with Warp 4 (1996!)

needs to get explicitly activated

switchrx.cmd

direct interface to SOM (and DSOM)

pre-requisites

documented in "somreq.doc" which can be found in the directory

containing the ORX examples together with the SOM animal

example, e.g.

built with SOMObjects 2.1 toolkit or higher (for dynamically finding infos

via the Interface repository)

SOM class must be in a DLL (along the SOMIR-environment path

variable) with a defined "SOMInitModule" routine

OUT and INOUT arguments

support via the predefined Object Rexx classes

found in "\os2\dlfclass.cmd"

(Object Rexx: Extending the WPS ...), page 10

Page 11

Object Rexx and SOM (ORX, 2)

Object-oriented version of the great Rexx-Interpreter

direct interface to SOM (and DSOM) (continued)

allows to use any SOM/DSOM class

allows to send any SOM/DSOM message

allows to specialiize SOM/DSOM classes

SOM classes appear as Object Rexx classes

sending messages to SOM objects as simple as sending

messages to ORX objects (ORX message operator: twiddle

)

(Object Rexx: Extending the WPS ...), page 11

Page 12

Object Rexx and SOM (ORX, 3)

Object-Rexx example of querying the SOM Interface

Repository (SIR)

gets access to the SOM Interface Repository Framework

queries all SOM classes available in the system

iterates over received container, displays names of SOM

classes

frees the resources reserved by the SIR framework

(Object Rexx: Extending the WPS ...), page 12

Page 13

/* querying the SOM interface repository with Object REXX */

aRepository

= .

somClassMgrObject

_get_somInterfaceRepository

SAY

"repository:"

(

aRepository

)

"of class:"

(

aRepository

~class)

SAY

aContainer

aRepository

contents

(

"InterFaceDef"

.true)

SAY

"aContainer:"

(

aContainer

)

"items"

(

aContainer

items

)

length

LENGTH

(

aContainer

items

)

anItem

OVER

aContainer

SAY

RIGHT

(

i,length

)

"id:"

LEFT

(

anItem

_get_id

)

,35

)

"name:"

(

anItem

_get_name

)

anItem

somFree

END

aRepository

somFree

exit

::ROUTINE

RETURN

"["

|| arg(

) ||

"]"

/* class to get access to SOM */

::CLASS

Test

PUBLIC

EXTERNAL

'SOM SOMObject'

"query_SIR.cmd" - Program

(Object Rexx: Extending the WPS ...), page 13

Page 14

"query_SIR.cmd" - Output

(Fragment)

repository: [a Repository] of class: [The SOMProxy class]

aContainer: [an Array] items [423]

1 id: [::SOMObject] name: [SOMObject]

2 id: [::Sockets] name: [Sockets]

3 id: [::AnyNetSockets] name: [AnyNetSockets]

4 id: [::Contained] name: [Contained]

5 id: [::AttributeDef] name: [AttributeDef]

6 id: [::BOA] name: [BOA]

7 id: [::SOMEEvent] name: [SOMEEvent]

8 id: [::SOMEClientEvent] name: [SOMEClientEvent]

9 id: [::Context] name: [Context]

10 id: [::ConstantDef] name: [ConstantDef]

11 id: [::Container] name: [Container]

12 id: [::SOMPEncoderDecoderAbstract] name: [SOMPEncoderDecoderAbstract]

13 id: [::SOMPAttrEncoderDecoder] name: [SOMPAttrEncoderDecoder]

... cut ....

122 id: [::TypeDef] name: [TypeDef]

123 id: [::SOMEWorkProcEvent] name: [SOMEWorkProcEvent]

124 id: [::WPObject] name: [WPObject]

125 id: [::M_WPObject] name: [M_WPObject]

126 id: [::WPFileSystem] name: [WPFileSystem]

127 id: [::M_WPFileSystem] name: [M_WPFileSystem]

128 id: [::WPFolder] name: [WPFolder]

129 id: [::M_WPFolder] name: [M_WPFolder]

130 id: [::WPDataFile] name: [WPDataFile]

131 id: [::M_WPDataFile] name: [M_WPDataFile]

132 id: [::WPAbstract] name: [WPAbstract]

133 id: [::M_WPAbstract] name: [M_WPAbstract]

... cut ....

423 id: [::M_OverrideFlWorkerEx] name: [M_OverrideFlWorkerEx]

(Object Rexx: Extending the WPS ...), page 14

Page 15

SOM-Animal, SOM-Dogs (1)

contained in Object Rexx examples for SOM

part of the Object Rexx package downloadable from IBM

for free or from DevCon ("Developer Connection")

Definition of SOM-classes as IDL and C-programs

"Animal" (superclass of "Dog")

methods: _get_name, _set_name, _get_sound, _set_sound,

_get_genus, _get_species,

talk

, display

"Dog" (superclass of "BigDog" and "LittleDog")

methods: _get_breed, _set_breed, _get_color, _set_color

overrides: _get_genus, _get_species, display

"BigDog"

overrides method: talk

"LittleDog"

overrides method: talk

(Object Rexx: Extending the WPS ...), page 15

Page 16

SOM-Animal, SOM-Dogs (2)

Object Rexx Program

/* derived from IBM's animal.cmd example */

spot

= .

dog

~new

Say

"spot's default name:"

spot

say

"spot's ClassName: "

spot

somGetClassName

say

"display"

; spot

display

say

"now talk, spot:"

; spot

talk

say

sadie

= .

bigDog

~new

/* Create new Big Dog Object */

sadie

setup

(

'Sadie'

'German Shepard'

'black and tan'

'Steve'

)

say

"sadie's default name:"

sadie

say

"sadie's ClassName: "

sadie

somGetClassName

say

"display:"

; sadie

display

say

"now talk, sadie:"

; sadie

talk

/* import some SOM Classes to use */

::Class

Dog

Public EXTERNAL

'SOM Dog'

::Class

BigDog

Public EXTERNAL

'SOM BigDog'

::method

setup

/* setup object */

expose

owner

use

arg name

, breed, color, owner

/* Owner assign on use Arg.... */

self~

_set_name

(name)

/* Set the SOM attribute */

self~

_set_breed

(

breed

)

self~

_set_color

(

color

)

self~

objectName

= name

/* set up the object's name to be the name as well */

::method

display

/* display attribute values */

expose

owner

say

'The Big <'

self~

_get_color

'> Dog <'

self~

_get_name

'> is owned by <'

owner

'>'

(Object Rexx: Extending the WPS ...), page 16

Page 17

SOM-Animal, SOM-Dogs (3)

Object Rexx Program - Output

spot's default name: a Dog

spot's ClassName: Dog

display

The animal named (Genus: Canis, Species: Familiaris) says:

It's breed is and its color is .

now talk, spot:

sadie's default name: Sadie

sadie's ClassName: BigDog

display:

The Big <black and tan> Dog <Sadie> is owned by <Steve>

now talk, sadie:

WOOF WOOF

(Object Rexx: Extending the WPS ...), page 17

Page 18

Object Rexx and WPS (1)

Direct WPS-support

"wpsinst +"

faster

"wpuser.cmd"

serves as "startup.cmd" for starting WPS

called by the direct Object Rexx WPS-support

e.g. defining WPS-specializations in Object Rexx and making them

available each time the WPS starts up

support definitions

"\os2\wpsysobj.cmd"

defines access to most used WPS-classes by placing them into

Object Rexx' global environment ".environment"

accessible as environment symbol

(Object Rexx: Extending the WPS ...), page 18

Page 19

Object Rexx and WPS (2)

Direct WPS-support

support definitions (continued)

"\os2\wpconst.cmd"

defines most important WPS constants and stores them in the

directory "wpconst"

stored in the global environment

accessible as the environment symbol ".wpconst"

"\os2\wpfind.cmd"

finds WPS-object by the given name

can be called from the command line or from within an Object Rexx

program

demonstrates usage of WPS-methods from Object Rexx

(Object Rexx: Extending the WPS ...), page 19

Page 20

Object Rexx and WPS (3)

Password Protected Folder

Choose class to specialize

"WPFolder"

Choose methods to override

"wpSetup"

"wpSaveState"

"wpRestoreState"

"wpOpen"

"wpClsQueryTitle"

use IBM's "VREXX.ZIP" (author: Steve Lamb) for

GUI-interface

require this class in "wpuser.cmd"

(Object Rexx: Extending the WPS ...), page 20

Page 21

Object Rexx and WPS (4)

Password Protected Folder (p1)

/* source: Rick McGuire (appr. 1996/1997), adapted: 2000-03-04;

---rgf, wuw; (using VREXX.ZIP and changing from WPDLF to DLF-data type classes)

using VREXX.ZIP, ews from Steve Lamb (IBM)

call

RxFuncAdd

'VInit'

'VREXX'

'VINIT'

Vinit

() =

"ERROR"

then

/* error loading VRexx-functions */

do call

VExit

/* clean-up */

raise syntax

array (

"VREXX.Vinit()"

)

/* abort program */

end

.local~

lock_icon

= STREAM(

"REXX.ICO"

"C"

"QUERY EXISTS"

)

.environment~

WPLockFolder

= .

WPLockFolder

/* make class available */

::REQUIRES

DLFClass

/* needs the support for INOUT/OUT datatypes */

(Object Rexx: Extending the WPS ...), page 21

Page 22

Object Rexx and WPS (5)

Password Protected Folder (p2)

::CLASS

VXPWPrompts

mixinclass

object

::METHOD

ask4Password

/* ask for a password */

use arg

title, prompt

buttons

/* use "OK"- and "CANCEL"-buttons */

prompt

/* prompt */

if arg(

"E"

) then

prompt

else

prompt

'Password'

width

1; width

/* widths in character units */

hide

1; hide

= .true

/* don't echo PW */

answer

1; answer

/* default value: empty string */

call

VDialogPos 50, 50

/* center message box on screen */

button

VMultBox

(

title,

"prompt"

"width"

"hide"

"answer"

, buttons

)

button

'OK'

then return

answer

/* return entered password */

return .nil

/* "CANCEL" pressed; indicate no PW entered */

::METHOD

displayError

use arg

msg

while

msg

pos =

length

(

msg

)

if pos >

then

/* VRexx allows 80 chars per msg-line only */

do pos = lastpos(

" "

, msg, 80

)

/* try to break at a blank */

if pos =

then pos =

/* no blank in first 80 chars, force break */

end

msg

substr

(

msg, 1,

pos)

/* assign chunk to msg-stem */

msg

substr

(

msg,

pos+

)

end

msg

/* assign message */

call

VDialogPos 50, 50

/* center message box on screen */

return

VMsgBox

(

'Important error message!'

"msg"

, 1

)

/* show OK-button only */

(Object Rexx: Extending the WPS ...), page 22

Page 23

Object Rexx and WPS (6)

Password Protected Folder (p3)

::CLASS

SMPPWChange

SUBCLASS

WPAbstract

::METHOD

wpOpen

use arg

handleContainer, view, params

view

then Do

/* Opening Default view? Dbl-click */

lockf

= self~

wpQueryFolder

/* Get our containing lock folder */

/* Ask for new password */

newpw

lockf

ask4Password

(

'New LockFolder Password'

'Enter New Password'

)

newpw

\= .nil Then Do

/* Get a new password? */

lockf

password

newpw

/* Yup, set new pw. */

lockF

wpSaveImmediate

/* Save object state (PW) */

End

return

End

/* Forward wpOpen to super class to handle. */

forward class (super)

(Object Rexx: Extending the WPS ...), page 23

Page 24

Object Rexx and WPS (7)

Password Protected Folder (p4a)

::CLASS

WPLockFolder

SUBCLASS

WPFolder

INHERIT

VXPWPrompts

::METHOD

wpclsQueryTitle

CLASS

return

'LockFolder'

::METHOD

init

expose

password

self~

init

:super

/* let superclass initialize 1t */

/* Create object to allow PW Change */

smpPwChange

~new(

'Change Password'

'ICONFILE='

|| .

lock_icon

';'

self

, 1

)

var(

'PASSWORD'

) Then

/* PW initialized via SetupString? */

password

/* Nope, give default '' */

::METHOD

wpOpen

expose

password

use arg

handleContainer, view, params

password

then

/* no password set? */

return self~

wpOpen

:super(

handleContainer, view, params

)

/* go ahead and open this*/

/* Ask user for password. */

enterpw

= self~

ask4Password

(

'Locked Folder Password'

'Enter Password'

)

password

enterPw

then Do

/* Was correct password entered */

/*Yup, forward to WPFolder top Open */

return self~

wpOpen

:super(

handleContainer, view, params

)

End

else Do

/* Incorrect pw entered. */

reply .false

/* Return failure, and return to WPS */

guard off

/* Now display error to user. */

self~

displayError

(

'LockFolder Error! [should be: "'

password

"]"

)

End

(Object Rexx: Extending the WPS ...), page 24

Page 25

Object Rexx and WPS (8)

Password Protected Folder (p4b)

::METHOD

wpSetup

use arg

setupString

maxLength

strLength

= .

DLFULong

~new(

maxLength

)

/* Will allow for up to 64 char PW */

/* Get INOUT String parm */

str

= .

DLFString

~new~~

_set_maxSize

(

maxLength

)

/* see if setup string has PW */

if self~

wpScanSetupString

(

setupString,

'PASSWORD'

, str, strLength

) then

self~

password

str

asString

/* Yup, set password. */

return self~

wpSetup

:super(

setupString

)

/* Superclass does remainder. */

::METHOD

scrollTitle

unguarded

/* unguarded, want to run concurrently*/

title

= self~

wpQueryTitle

/* Get current title */

/* Will scroll twice. */

title

length

/* For length of title. */

self~

wpSetTitle

(

right

(

left

(

title, i

)

, title

length

))

/* display 1st 1 chars of titl

end

(Object Rexx: Extending the WPS ...), page 25

Page 26

Object Rexx and WPS (9)

Password Protected Folder (p4c)

::METHOD

password

ATTRIBUTE

::METHOD

wpSaveState

/* Save the password data */

self~

wpSaveString

(self~

somGetClassName, 1,

self~

password

)

return self~

wpSaveState

:super

/* Let parent save any state. */

::METHOD

wpRestoreState

self~

initButtons

/* make sure OREXX side initialized. */

size

= .

DLFULong

~new

/* Get DLFUlong for size query. */

/* Retrive size of string for restore */

self~

wpRestoreString

(self~

somGetClassName, 1,

.nil

, size

)

/* Create DLFString large enough to contain the string, plus NULL */

str

= .

DLFString

~new~~

_set_maxSize

(

size

_get_value

)

/* Now get saved password */

self~

wpRestoreString

(self~

somGetClassName, 1, str, size

)

self~

password

str

asString

/* Save password state value. */

/* let parent restore state. */

return self~

wpRestoreState

:super(arg(

))

(Object Rexx: Extending the WPS ...), page 26