Web Enablement: Challenges and Solutions http://www.uark.edu/basis/UAWEB/Challenges.html

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Web EnablementChallenges and Solutionshttp//ww
w.uark.edu/basis/UAWEB/Challenges.html

• David Wimberly
• University of Arkansas
• wdw_at_uark.edu

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Web Enablement Challenges

1. Field help
2. Selecting data
3. Accommodating the browser Back button
4. Stateless forward and backward browsing of ADABAS
   data

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Background

• Long term Natural/ADABAS shop
• All non-student systems developed in house --
  BASIS
• Late to web enable
• Inexperienced and unschooled
• Com-Plete v6.1 HTTP Server
• Natural as the CGI language
• Natural code generated via Natural ISPF macros

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1. Field Help

• Traditionally available on 3270 terminals as help
  windows
• Solution, three web examples
• Technique
• Selecting help and opening a window
• Passing parameters to the help program
• Returning a selected value

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Example of 3270 field help

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Web Field Help Example

• Field definition only

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Web Field Help Example

• Field with discrete values

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Web Field Help Example

• Field definition with search criteria for a table

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Web Field Help Example

• Browse of selectable table values

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Selecting Help Opening a Window

• lta href""
• target"p8EPODIRM"
• tabindex"-1"
• title"Help for Employee Privacy Code"
• onclick"window.open(
• 'uwohfddv',
• 'p8EPODIRM',
• 'resizable,scrollbars,width400,height400')
  
• return false"gt
• Privacy Code ltbr /gt(for directory)lt/agt

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Passing Parameters In

• onclick"window.open(
• 'uwohfddv?pAAHR
• pFldEMP-PRIVACY-CD
• wFmwebForm
• wFldEMP_PRIVACY_CD',
• 'p8EPODIRM',
• resizable,scrollbars,width400,height400')
• return false"

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Returning a Selected Value

• ltscript language'JavaScript'gt
• lt!-- Begin
• function setVC (dVal) // Set opener Value and
  Close
• opener.document.webForm.EMP_PRIVACY_CD.valuedV
  al
• window.close()
• // End --gt
• lt/scriptgt

lta href'' title'Choose this entry'
onClick'setVC("1") return false'gt1lt/agt
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Field Help Summary

• Using JavaScript and the DOM
• Invoke help lta
• Open a window onclickwindow.open(
• Pass parameters program?parmvalue
• Select a value lta
• Return the value opener.document.form.field.value
  

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2. Selecting Data

• Browse-Select user interface
• Web examples
• Solution
• Hidden form fields
• Entry selection
• Field assignment

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Browse of Purchase Orders

• Action selected to view invoices for the selected
  PO

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Browse of Invoices for a PO

• Action selected to view the invoice data

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View of Invoice Data

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Hidden Form Fields

• HTML form fields are needed to pass selection
  identifiers to the next program
• These fields are behind the scene since the user
  is not keying values into them

ltinput type"hidden" name"PO_NO"gt
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Entry Selection

• Once again we use a null link to execute a
  JavaScript function

lta href'' tabindex'1' title'Choose
this entry' onClick'setVS(1) return
false'gt6001260lt/agt
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Field Assignment

• JavaScript assigns the hidden form field and
  submits the form

function setVS (le_x) // Set Value and Submit
listEl1 new Array() listEl11"6001260"
listEl12"6001264" document.webForm.PO_NO.
valuelistEl1le_x document.webForm.actionReq
.value"Execute" document.webForm.submit()
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Selecting Data Summary

• Hidden form fields
• ltinput typehidden
• Entry selection
• lta onclick
• Hidden field assignment document.form.field.value
  
• Form submission document.form.submit()

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3. The BACK Button

• The issue state on the mainframe really is
  meaningless if the user can interact from any
  prior page
• Web example
• Solution maintain minimum state information
  within each page via hidden fields
• First/Last ISN and occurrence for paging
• Program stack for return

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Browse all Services by Key Word
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Browse Invoices Search Criteria
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Browse Invoices for Vendor
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Back twice, then Page Back
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First/Last ISN and Occurrence

• Using these we access the first/last record to
  restore our search key values and then page
  (read) forward or backward

ltinput type"hidden" name"FirstISNOcc"
value"734.000"gt ltinput type"hidden"
name"LastISNOcc" value"738.000"gt
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Program Stack, Titles

• List of menus/functions visited

ltinput type"hidden" name"title_rs1"
value"Main Menu"gt ltinput type"hidden"
name"title_rs2" value"Purchasing/Payab
les Menu"gt ltinput type"hidden"
name"title_rs3" value"Purchase Orders"gt
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Program Stack, Program Names

• Natural program names for those functions and the
  action and search type selected (retained as
  index values)

ltinput type"hidden" name"psPrgmID"
value"UWOMENUH11UWOMENUH11UPOBPO 21"gt
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Program Stack, First ISN per Level

• ISN and occurrence of the first record displayed
  at each level (the occurrence is only retained
  when necessary, negative values indicate page
  back was allowed)

ltinput type"hidden" name"psFirstISN"
value"510-734"gt
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BACK Button Summary

• Maintain state information within each page via
  hidden fields
• For our browse models
• First and last ISN occurrence
• Info for each level (menu hierarchy)
• Title
• Program with action and search type
• First ISN occurrence

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4. Stateless Browsing (ADABAS)

• No active loop required
• Thanks to STARTING WITH ISN
• Backward browsing
• Thanks to READ/HISTOGRAM IN VARIABLE DIRECTION
• Descriptor types
• Regular descriptors
• MU descriptors
• Unique PE descriptors

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Regular Descriptor, Search Value

• Search value (key) definition

DBV Search key for Search Type VEND 1 SK-VEND
2 VENDOR-NO
(P6) 2 DATE-ORDER-EFFECTIVE
(D) 1 REDEFINE SK-VEND
2 SK-VEND (B8)
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Regular Descriptor, Restore Keys

• GET and MOVE BY NAME used to restore the search
  key after a paging request

GET DBV START-ISN / Get the previous
/ first/last
record MOVE BY NAME DBV TO SK-VEND / Pull its
starting key
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Regular Descriptor, Read

• Data base READ and subsequent check for the same
  vendor

RVEND. READ DBV IN VARIABLE DIRECTION BY
VENDOR-DATE-KEY SK-VEND STARTING WITH ISN
START-ISN IF DBV.VENDOR-NO NE
SK-VEND.VENDOR-NO / So we don't page across
high order keys ESCAPE BOTTOM END-IF
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MU Descriptor, Search Value

• Search value (key) definition for our Browse all
  Services
• Applicable to super descriptors composed from an
  MU or elementary MU fields

DBV Search key for Search Type 3 - KEYW 1
SK-KEYW 2
ACCESS-GROUP-CD (A4) 2
MENU-KEYWORD (A12)
1 REDEFINE SK-KEYW 2
SK-KEYW (A16)
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MU Descriptor, View

• Use HISTOGRAM READ because
• With READ alone you do not know which descriptor
  value (occurrence) was used to access the record
• You cannot use HISTOGRAM and FIND because there
  is no FIND DESCENDING

1 HKEYWV VIEW OF WEB-MENU 2
ACCESS-KEYWORD-KEY (1) 2 REDEFINE
ACCESS-KEYWORD-KEY 3 ACCESS-GROUP-CD
(A4) 3 MENU-KEYWORD (A12)
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MU Descriptor, Restore Keys

• Statements to restore the search key after a
  paging request (with the occurrence reference)

GET DBV START-ISN / get the previous
/ first/last record
SK-KEYW.MENU-KEYWORD / and pull its starting
key DBV.MENU-KEYWORD(START-OCC)
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MU Descriptor, Histogram

• HISTOGRAM to obtain the key word values

/ Set the fixed access group SK-KEYW.ACCESS-GROU
P-CD WSI.ACCESS-GROUP-CD / Histogram
to get the keywords
HKEYW.
HISTOGRAM HKEYWV IN VARIABLE DIRECTION
FOR ACCESS-KEYWORD-KEY FROM SK-KEYW IF
HKEYWV.ACCESS-GROUP-CD NE
SK-KEYW.ACCESS-GROUP-CD ESCAPE BOTTOM
(HKEYW.) END-IF
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MU Descriptor, Starting ISN

• The READ may be a continuation only for the 1st
  descriptor value

IF COUNTER(HKEYW.) GT 1
/ Only restrict the records in the
READ for the / first key obtained RESET
START-ISN / Will be ignored when used in
/ STARTING WITH ISN (descending
/ as well as ascending) END-IF
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MU Descriptor, Read

• Read the records with the descriptor value

/ Read the data
RKEYW.
READ DBV IN VARIABLE
DIRECTION WITH ACCESS-KEYWORD-KEY
HKEYWV.ACCESS-KEYWORD-KEY(1) STARTING WITH
ISN START-ISN IF NOT HKEYWV.MENU-KEYWORD
DBV.MENU-KEYWORD() ESCAPE BOTTOM
END-IF
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MU Descriptor, Wrap Around

• Do not report the same record twice when adjacent
  keywords exist within the same record

IF NOT HKEYWV.MENU-KEYWORD DBV.MENU-KEYWORD()
/ Ensure we don't cycle around
or (DIRECTION 'A'
AND ISN(RKEYW.) LE START-ISN)
OR (DIRECTION 'D' AND START-ISN NE
0 AND
ISN(RKEYW.) GE START-ISN) ESCAPE
BOTTOM END-IF

START-ISN ISN(RKEYW.)
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PE Descriptor

• You cannot page back (without wasted I/O) in a
  stateless environment with a non-unique PE type
  descriptor without FIND DESCENDING
• See enhancement proposal 958 on Quest or
  Servline24 and add your comments

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Unique PE Descriptor, Search Key

• Search value definition

DBV Search key for Search Type RACT 1
SK-RACT 2
REVIEWER-DESK-ID (A8) 2
RPI (L) INIT ltTRUEgt 2
APPLICATION-ID (A8) 2
COMMAND-ID (A4) 2
TIME-TXN-REQUESTED (T) 1
REDEFINE SK-RACT 2
SK-RACT (A28)
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Unique PE Descriptor, View

• HISTOGRAM view to obtain the descriptor values

HGV for PE type descriptor 1 HGV
VIEW OF TARGET-TXN 2
REV-RPI-ACMD-TRTIME-KEY
2 REDEFINE REV-RPI-ACMD-TRTIME-KEY
3 REVIEWER-DESK-ID (A8)
3 RPI (L)
3 APPLICATION-ID (A8)
3 COMMAND-ID (A4)
3 TIME-TXN-REQUESTED (T)
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Unique PE Descriptor, Restore Keys

• Statements to restore the search key after a
  paging request

GET DBV START-ISN / get the previous
/ first/last record MOVE
DBV.APPLICATION-ID TO SK-RACT.APPLICATION-ID
MOVE DBV.COMMAND-ID TO
SK-RACT.COMMAND-ID MOVE
DBV.REVIEWER-DESK-ID(START-OCC) TO
SK-RACT.REVIEWER-DESK-ID MOVE DBV.TIME-TXN-REQUEST
ED TO SK-RACT.TIME-TXN-REQUESTED
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Unique PE Descriptor, Histogram

• HISTOGRAM to obtain the PE descriptor values

HRACT.
HISTOGRAM HGV IN VARIABLE DIRECTION
FOR REV-RPI-ACMD-TRTIME-KEY
STARTING WITH SK-RACT
IF HGV.REVIEWER-DESK-ID NE
SK-RACT.REVIEWER-DESK-ID ESCAPE BOTTOM
(HRACT.) END-IF
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Unique PE Descriptor, FIND

• FIND the record with the unique descriptor value

/ Treat this descriptor as if it is unique
FRACT.
FIND (1) DBV WITH
REV-RPI-ACMD-TRTIME-KEY
HGV.REV-RPI-ACMD-TRTIME-KEY
END-FIND
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Stateless Browsing Summary

• Thanks to READ/HISTOGRAM DESCENDING and
  STARTING WITH ISN we have efficient forward and
  backward browsing of ADABAS
• Regular descriptors, MU type descriptors, and
  Unique PE type descriptors
• Enhancement needed for non-unique PE type
  descriptors (proposal 958)
• FIND DESCENDING

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Presentation Summary

• Techniques for
• Implementing field help,
• Selecting data,
• Working with the browser BACK button, and
• Stateless forward and backward browsing of ADABAS
  files.

Thank You