BP0370: PUBLISH or Perish

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BP0370 PUBLISH or Perish

• Breathing New Life into Old Applications

Glen West (gwest_at_techsmiths.com) President,
TechSmiths, Inc.
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Agenda

• Why do I want to know this stuff? Whats in it
  for ME?
• Parameter models
• If I dont PUBLISH, will I really perish?
• Lets see what trouble we can get ourselves into
  with Pub/Sub
• What Pub/Sub is NOT
• Related topics, tips, tricks, and resources

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Agenda

• Why do I want to know this stuff? Whats in it
  for ME?
• Parameter models
• If I dont PUBLISH, will I really perish?
• Lets see what trouble we can get ourselves into
  with Pub/Sub
• What Pub/Sub is NOT
• Related topics, tips, tricks, and resources

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Whats in it for ME?

• We all have an old skeleton in the closet.
• Old applications/new functionality
• How to migrate to the future without burning
  bridges to the past?
• Parameters
• Dynamic Query/Find
• Publish/Subscribe

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Agenda

• Why do I want to know this stuff? Whats in it
  for ME?
• Parameter models
• If I dont PUBLISH, will I really perish?
• Lets see what trouble we can get ourselves into
  with Pub/Sub
• What Pub/Sub is NOT
• Related topics, tips, tricks, and resources

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Parameter Models

• Classic A series of single-record tables. The
  tables usually represent applications/modules,
  one field per parameter.
• Generic single table, one record per parameter
• Tree Structure nested parameters in a tree
• Hybrid Classic moving toward tree.

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Hybrid Parameter Tree
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Hybrid Parameter Tree
Create a dynamic widget Combo Box
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Hybrid Parameter Tree
Widget Validation Build combo box from this data
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Hybrid Parameter Tree
Dynamic Query Get the data from/put the data
back into this field
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Key Dynamic Queries

• Building the Query (simple)
• Define Variable l-hQuery as handle
  no-undo.
• Define Variable l-hBuffer as handle
  no-undo.
• Define Variable l-query as char
  no-undo.
• create buffer l-hBuffer for table i-table.
• Create query l-hQuery.
• l-hQueryset-buffers(l-hBuffer).
• Assign l-query 'for each ' i-table.
• l-hQueryquery-prepare(l-query).
• l-hQueryquery-open.
• NOTE Look at get-list-value-pairs procedure in
  the code samples (list-value.p)

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Dynamic Parameters

• So, now we can dynamically find parameter values.
• How do we access them in the application?
• How do we stop using the old parameters?
• How do we know when we can get rid of the old
  parameter file completely?

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Agenda

• Why do I want to know this stuff? Whats in it
  for ME?
• Parameter models
• If I dont PUBLISH, will I really perish?
• Lets see what trouble we can get ourselves into
  with Pub/Sub
• What Pub/Sub is NOT
• Related topics, tips, tricks, and resources

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PUB/SUB Basics

• Syntax
• Standards (i.e. event naming)
• Mechanics (how the components chat)

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SUBSCRIBE Syntax

• SUBSCRIBE
• PROCEDURE subscriber-handle
• TO event-name
• IN publisher-handle ANYWHERE
• RUN-PROCEDURE
• local-internal-procedure
• NO-ERROR

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PUBLISH Syntax

• PUBLISH event-name
• FROM publisher-handle
• ( parameter , parameter ... ) .

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Naming Standards

• Depends on application/toolset architecture.
• Will you be integrating with other vendors
  products?
• Might you be changing infrastructure?
• Prefixes. Options
• Who will be responding (APP-, UI-, TOOL-)
• Application or module (AP-, AR-)
• Global services (no prefix)
• Instance based (SCOP Subscribe SUBSCRIBE to
  w-instance )

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The PUB/SUB Process
Named Event Table
Progress Session (Agent)
Program A (Session Svcs)
Program B (Entry)
Program C (Dialog Box)
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The PUB/SUB Process
Named Event Table
Startup
Progress Session (Agent)
Launch Persistent
Program A (Session Svcs)
Program B (Entry)
Program C (Dialog Box)
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The PUB/SUB Process
Named Event Table
Progress Session (Agent)
Subscribes
Program A (Session Svcs)
Program B (Entry)
Program C (Dialog Box)
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The PUB/SUB Process
Named Event Table
Progress Session (Agent)
Run Proxy
Publish Get Preference
Program A (Session Svcs)
Program B (Entry)
Program C (Dialog Box)
Publish Get-Preference (background color,
output w-bg-color, output w-success).
Publish
Run get-preference in hSessionSvc (background
color, output w-bg-color, output w-success).
Run Proxy
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The PUB/SUB Process
Named Event Table
Progress Session (Agent)
Subscribe Get-Parent
Subscribe Restrictions
Run
Program A (Session Svcs)
Program B (Entry)
Program C (Dialog Box)
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The PUB/SUB Process
Named Event Table
Progress Session (Agent)
Run Proxy
Unsubscribe Get-Parent
Publish Get-Parent
Subscribe Results
Program A (Session Svcs)
Program B (Entry)
Program C (Dialog Box)
Subscribe Procedure hParent to Results in
this-procedure.
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The PUB/SUB Process
Named Event Table
Progress Session (Agent)
Run proxy
Publish Restrictions
Program A (Session Svcs)
Program B (Entry)
Program C (Dialog Box)
Publish Restrictions from hParent
(this-procedure, output w-restrictions).
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The PUB/SUB Process
Named Event Table
Progress Session (Agent)
Run Proxy
Publish Results
Program A (Session Svcs)
Program B (Entry)
Program C (Dialog Box)
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PUB/SUB Code Samples

• The conference CD, and our website, has all the
  code samples from this presentation.
• Sess-start.p is the startup procedure (-p)
• Sess-svc.p is the session services procedure used
  so far in these examples
• entryproc.p is the entry program
• Rep-db.p is the dialog box
• Now lets watch it in action (demo)

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Agenda

• Why do I want to know this stuff? Whats in it
  for ME?
• Parameter models
• If I dont PUBLISH, will I really perish?
• Lets see what trouble we can get ourselves into
  with Pub/Sub
• What Pub/Sub is NOT
• Related topics, tips, tricks, and resources

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Setting Up a PUB/SUB Architecture

• A Session Services procedure
• A UI Services procedure
• Instance Based management procedure

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Session Services

• Potential uses for session services procedures
• Manage parameters, preferences
• Sequence generation (Note using a Progress
  AppServer to get outside the transaction)
• Managing UI Instances
• Common math routines (eg currency exchange, UOM
  conversion)
• Manage context and record-currency between
  programs

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UI Services

• Potential Uses of a UI Services procedure
• Manage screen placement of UI objects (obviously)
• Provide custom user interface experiences to
  different users
• Manage currency of data (what record are we
  working on?)
• Standardize inter-object communication

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Instance Management

• What can you do with an Instance Manager
• Maintain context between entry and lookup
• Ensure the lookup returns the data to the correct
  parent.
• Manage child UI objects (kill the child when the
  parent dies)
• Handle-independent communications
• PUBLISH/SUBSCRIBE event.
• GLOB Subscribe SUBSCRIBE TO w-instance

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Real-Life Pub/Sub Uses

• Inter-object Communication
• Process Messaging
• Utilities (date/time, foreign currency, math
  functions)
• Preferences, ini-files, registry settings,
  parameters.
• Performance timing routines (start/stop/hack)
• Other stuff?

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Agenda

• Why do I want to know this stuff? Whats in it
  for ME?
• Parameter models
• If I dont PUBLISH, will I really perish?
• Lets see what trouble we can get ourselves into
  with Pub/Sub
• What Pub/Sub is NOT
• Related topics, tips, tricks, and resources

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What PUB/SUB is NOT

• Inter-session communication. You cannot talk to
  another user or another Progress session.
• Ill read it when I want. If you dont consume
  the message when issued, it goes away.
• SonicMQ is a java messaging system (JMS) that
  handles both of the above.
• You can hear all about SonicMQ here except you
  needed to do it BEFORE this session

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Agenda

• Why do I want to know this stuff? Whats in it
  for ME?
• Parameter models
• If I dont PUBLISH, will I really perish?
• Lets see what trouble we can get ourselves into
  with Pub/Sub
• What Pub/Sub is NOT
• Related topics, tips, tricks, and resources

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Related Topics

• Since this is the last session, you may have
  missed them.
• BP2110 Introduction to SonicMQ
• BP2160 Design Patterns for Messaging
• BP1790 Messaging with the Sonic-to-4GL adapter
• BP2170 Sonic in a J2EE Environment
• BP1310 Designing a Dynamics Application

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Tips, Tricks Resources

• Most likely bug Mismatch in signature
• Progress 9.1A REQUIRED an input parameter on a
  publish IF there was an output parameter.
• Dynamic event names
• The PEG on PUB/SUB Peter van Dam
  http//www.v9stuff.com/publish.htm
• Synchronous but semi-random
• Remember Publishing as someone else, Subscribing
  someone else, subscribing to yourself.

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Conclusion
?

• You can use these new techniques to weave new
  functionality into your existing applications.
• Questions? Answers? Rotten tomatoes to throw at
  speaker?
• The answer is, of course 42