01 Class Structures and Hierarchy Design

7/29/2019 01 Class Structures and Hierarchy Design

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CLASS STRUCTURES AND

HIERARCHY DESIGN

20 % of EXAM

MATERIAL FOR PRPC CERTIFICATION


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System Architecture Understand the difference between a Business Rules Engine (BRE)and a Business Process Management System(BPMS)

Business Rules Engine (BRE) is a software system that manages business rules, it

separates the business rules from the application code.

Engine Types

Inference

Derives a conclusion based on a knowledge base

Answers questions when a user or application submits them

Example: Should this customer be allowed a mortgage?

Reactive

Detects and reacts to patterns of events occurring Performs an action automatically when a certain rule is violated

Example: Alert a manager when certain items are out of stock

No User Interface

External systems communicate through open interfaces with the Rules Engine


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Business Process Management System (BPMS) is a software system which allows for the direct

execution of business processes. Removes the costly and time intensive development of process specific software

Allows the full business process to be defined Can invoke external services to perform business operations

Can send messages to human workers requesting they perform certain tasks

Can call a Business Rules Engine to make automated decisions

Provides a process driven User Interface

Pega Rules Business Rules Engine Separates business logic from your mission-critical applications and enables your enterprise

to capture, manage and execute your business policies and practices

Pega Rules Provides An inference engine to perform dynamic business decision making

A reactive engine using declarative rules that are used only when underlying data changes This combination of rule types and processing approaches provides

Rapid time to production Increased ROI


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Identify the elements that comprise Process CommandersJava EE architecture

PRPC Architecture Overview

Secure, scalable, upgradeable application framework based on a declarative objectmode

Shared UI components, business logic, and data model

Standard data model

Integrated tool set for extending the data model, business logic, and user interface Pre-built services designed specifically for BPM

Designed to integrate with an organizations existing IT infrastructure

Architecture Key Concepts

Application Server

Java

Java Enterprise Edition

Multi Tired Architecture

Enterprise Java Beans

Servlets

Java Server Pages

Java Data Base Connectivity


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Describe the function of each component of the process

commander architecture Application Serveris a software dedicated to the serving (running) of other

applications

Facilitates

Programming productivity

Provides dedicated standard APIs

Response to demand

Provides scalability, load-balancing, (re)configuration, deployment Integration with existing systems

Provides standard services

SOAP

Message Queue

DB Access

Security

Java is an object-oriented programming language developed by Sun Microsystems

Syntax is similar to C

Is compiled to byte code which is run by a Java Virtual Machine

Java Virtual Machines (JVM) are available for many different platforms

Java code can be run on any platform that provides a suitable JVM


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Java vs. JavaScript

Originally developed by Netscape

Is typically interpreted by a Web Browser

Does not use a JVM

Only similarity to Java is the C like syntax

Java Enterprise Edition is a platform for developing and running distributed multi-tier

architecture Java applications

Formerly known as Java 2 Platform, Enterprise Edition (J2EE)

The Java EE platform is defined by a specification

Platform vendors must agree to certain conformance requirements in order to

declare their products asJava EE compliant

Multi Tired Architecture is a client-server architecture in which an application is

executed by more than one distinct software agent

The Java EE standard facilitates a multi-tiered architecture

Often referred to as n-tier architecture

Client Tier

Web Tier

Data Tier

Web Browser

Java EE Platform

Database Server

Example


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Enterprise java Bean is a server-side component that encapsulates the business logic of an

application EJBs are deployed in an EJB container within the application server

Client Tier

Web Tier

Data Tier

Business TierEJB

Java Servlets are Java programming language classes that dynamically process

requests and construct responses

Servlets are deployed in a web container within the application server

Typically generate HTML

Client Tier

Web Tier

Business Tier

Data Tier

EJB

ServletsHTML


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Java Server Pages are Text based documents

May contain HTML tags

Contain Java specific tags

May contain Java code pieces

A JSP compiler is used to generate a Servlet from the JSP page

Typically produces HTML

Web Tier

JSP JSP Compiler Servlet HTML

Java Data Base Connectivity is an application programming interface (API)

specification for database connectivity

-Encodes database request statements in structured query language

(SQL)

Client Tier

Web Tier

Business Tier

Data Tier

JDBCSQL

SQL


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Describe how work objects and rules are stored in thedatabase

Users create work instances that are saved to the database while running an application

Work is stored as XML documents which are written to the database

Stored as Binary Large Objects (BLOB)

System Architects can select Work data to be stored in standard columns allowing

for improved reporting and querying

XML

Users

Work

Work Database

XML

System Architects modify and create object instances that are saved to the database

Known as Rules

Rules are stored as XML documents which are written to the rule repository databaseAt runtime the XML documents are parsed and converted to Java code for execution

XML

System Architects

XMLRulesJava

Rules Repository


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Reusability and Hierarchy Design Define reusability and its impact on application design

Reusability Of assets across an organization is integral to the success of a project

By gathering the right requirements, and applying the principles of reusability and class

hierarchy design heuristics, you will always create systems that deliver on the value

promised . Ultimately, the reusability requirements drive the selection of your class

hierarchy design pattern .

Describe the difference between applicationreusability and organization reusabilityApplication Assets are specific to an application and common to more than one business unit

For example, all divisions across BIG have some type of Policy Administration

Organization Assets common across multiple divisions or applications

For example, LDAP integration

Understand the difference between one Offapplication and a reusable applicationGeneralized

Define a common interface for its sub-application Defers some of or all of its implementation to application assets defined in its

sub-applications

The assets that an generalized application declares but does not implement are

called generalized assets.A solution framework is an generalized application


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Specialized

Applications that are not generalized are called specialized applications

One Off application is a specialized one.

Identify the scope of reusable components within acompanys organizational diagram

We can create reusable components for an organization, divisions and units and also for a

group of users. We can design these components where ever the similar kind of functionalityis seen across divisions, units and organizations.

Design and create an organizational structure comprised ofan organization, divisions, and business units

In PRPC the following rules are used for creating organization, Divisions, and Business Units.

Data-Admin-Organization

Data-Admin-OrgDivisionData-Admin-OrgUnit


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Understand the concept and benefits of building on acommon application layerIf we want to develop a frame work which can be used by different independent vendors to

implement solutions upon that we need to build a common application layer. This layer can

be reused and customized according to the requirements. The basic functionality will be

residing in this common application layer.

For example if we develop a application layer for a banking domain, the same can be used by

independent software vendors to develop/customize the application.

Design and implement reusable class structure withappropriate top, divisional, and class group levels and workclasses.

Always while designing the class structure, the best practice is we should apply class level

sense according to the business hierarchical structure of the organization.

Organization --- Division --- Unit levels can be transformed to

Top level class --- Divisional level --- Class group level with respect to PRPC. Each class group

level will be a unit / application where in different process can be initiated. By Default PRPC

is shipped with and Organization called Pega.com.


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Classes and Class Groups/ Work Pools Create Classes and Class GroupsA Class group is an instance of the Data-Admin-DB-ClassGroup. A class group instance causes

the system to store the instances corresponding to two or more concrete classes that have a

common key format in a single database table. Class groups are commonly used to cause the

system to store instances of similar or related Work- concrete classes together in one

relational database table.

While Creating the class group we need to specify the key for the group. Generally it ispyID.

Understand the purpose of a class group and its relation tothe applications database and a users work poolDifferent work types (classes derived from the Work- base class) are grouped in to one class

group and when this class group is added to a user in his access group, user can work on

through each work type of each class groups. Class groups so added are called as Work pools.Instances ofData-Admin-DB-Table are used for mapping the classes and class groups with DB

tables. At any point of time, if a class is not mapped to any DB table, its instances are

stored in its super classs mapped table. The principle is recursive.

All the classes belonging to the class group will have the same keys of the class group.


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Describe the difference between the abstract and concreteclassesAbstract Classes can contain any rule type

Cannot contain instances

Great for reuse

The name of a abstract class must end with a dash (-).

Concrete classes hold persistent objects, known as instancesNames must not end with a dash (-)

Names should define the type of work being performed.

Understand the concept of top-level and base classesTop level classes are always abstract and inherit from the @baseclass.

Top level class is an abstract class that has the ultimate base class @baseclass as parent but

is not one of the standard base classes.

@baseclass is called as the ultimate base class. And its immediate child classes like Data-,

Work-, Assign- etc are called as base classes.


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Understand the difference between pattern and directedinheritancePattern inheritance Causes a class to inherit rules from classes that match the prefix of the

class name. Uses prefix segments that are followed by a hyphen.

Directed inheritance is Is explicitly specified by the developer. It allows a class to inherit

from a class not related to its name. A base level class always has directed inheritance from

@baseclass .

A class can use both types of inheritance at the same time. It can have only one patternparent and one directed parent. Must always have a directed parent.

PRPC uses an algorithm to determine inheritance Known as the Rule Resolution algorithm.

For Determining Inheritance Pattern inheritance is used first, If the algorithm fails to

find any rules using pattern inheritance, it starts again using directed inheritance

While Creating the class, mentioning the direct inheritance is inevitable. Pattern inheritance

is optional. If pattern inheritance is mentioned by checking in the check box, Pattern

inheritance takes the precedence.


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Rule Sets and Rule Resolution Design and create a Rule set hierarchy and its prerequisitesA Rule Set is a container that stores a related group of business rules and provides:

Security

Version control

Ability to deploy your application in a different Process Commander environment

Rule Set Hierarchy Design


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Rule Set Hierarchy at runtime

Searches RuleSets in the order in which they appear in users Profile list

User Profile list is assembled from:

Requestor

Organization

Division

Access group


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Best Practice for Ordering RuleSets

Personal RuleSets first (happen automatically)

Production RuleSets RuleSets that are unlocked to allow changes

RuleSets in an Application rule RuleSets that are locked

Pega-ProCom, Pega-IntSvcs, Pega-WB

Pega-RULES (always last and happens automatically)

Rule Set Hierarchy at runtime

When editing a rule Not possible to guarantee what the profile of the user is

Therefore, RuleSet list of requestor is not used

A RuleSet list is generated from the rule being edited and its prerequisites


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Tips for Rule Set Hierarchy design

Limit the number of RuleSets to the minimum amount necessary

Create a RuleSet only if it has a reasonable chance of holding rules

Use the Initial Setup Wizard to create the organizational RuleSet

Use the Application Accelerator to create the first RuleSet needed for eachapplication

A RuleSet can inherit features from other, prerequisite RuleSets and also fromlower-numbered versions of itself

As a best practice, update the RuleSet Version rules created by the ApplicationAccelerator to identify Pega-ProCom:04-02 as a prerequisite to each of yourapplication RuleSets

Understand the Connection between Classes and RulesetsWhile creating a new class you need to Identify the RuleSet version number that

applies to the class. The Archive tools depend on this version. The Export Archive tool

includes this class instance if you export this RuleSet version or a higher-numbered

version.

However, version information in class rules is not used for rule resolution. You cannot

define multiple class rules with the same class name but different versions.


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Understand Ruleset versioning and why it is important toapplication development and configuration development


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Versioning at configuration management controls the exact application behavior, atdevelopment time it controls the access to the developers.

Understand how to provide users with access to RulesetsWe can add rulesets at either at Organization or at Division or at access group, but not at

the unit. It is not mandatory to add the rulesets either at Organization, division and the

access group. We can add at all these places, at the same time we can refrain by not adding

at any of these places.

Significance of adding rulesets at Organization: We can add one or more rulesets to

organization for providing access to all the users belonging to that organization to the

specified Ruleset. Assume an application like leave application which needs to be

accessed by all the employees of organization, and then perhaps we may like to add leave

applications rulesets at Organization level.

Significance of adding rulesets at Division: We can add one or more rulesets to division for

providing access to all the users belonging to that division. Assume an application like Loan

application of a bank which needs to be accessed only by the employees of Loans division,

then perhaps we may like to add Loan applications rulesets at Loan division level, so that

other divisions in the same organization can not have access the Ruleset


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Significance of adding rulesets at Access Group: We can add one or more rulesets to accessgroup when we think that security needs to be controlled basing on the specific job function.Assume that an application like Heart allocation request application is being developed forall the Project Managers in Virtusa for making resource requests for their projects. Then wecan think of adding this application Ruleset in an access group called PM, so that all PMsacross all the divisions in Virtusa can access this application.

Understand the reasons of locking rule setsYou can use the Security tab to lock the Ruleset by requiring developers to enter apassword when they update the Ruleset, or add or update version instances for the Ruleset.

We can avoid tampering/misuse of rules (assets) by locking the rule set when the applicationis shipped for production.

Describe rule resolution, how it works, and how it impactsrule set hierarchy design

Picking up right rule at right time is called as rule resolution. Process by which Process

Commander decides which rule (of a series of possible rules) will be used to execute anaction.


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Dynamic selection of rule involves the following steps Business process

Product

Organization

Ruleset and version

Date

Time Circumstance

Security

We have to design the rule set hierarchy considering the process of rule resolution. At run

time it checks for the order we have configured rule sets in the access group. We have to

check for where exactly a particular rule fits in the organization and accordingly we need to

create multiple rule sets to modularize the application into different rule set constituents.


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Availability of the rules: Availability is an important aspect of any rule for it to beconsidered by Rule resolution algorithm. pyRuleAvailable property represents whether agiven rule is available or not ? At any point of time, this property can be set with either ofthe following four values

YES : Indicates that this rule is available. Rules with a Yes value are visible torule resolution processing and executed.

NO : Indicates that is rule is not available and become invisible to the ruleresolution algorithm for all users (including yourself). The No setting is useful inexperimentation and troubleshooting to assess the effect of two rule versions.

Ex : If you are setting No status for a rule of version 01-01-03, still 01-01-01, 01-01-02, 01-01-04 of same rule are visible to rule resolution algorithm

BLOCKED : This is a stronger form of No because it affects all lower-numberedversions of the rule and it makes all lowered numbered including this version notto be visible to rule resolution algorithm. Note : A blocked rule does not preventrule resolution from finding (and running) higher-numbered versions

Ex: If you are setting BLOCKED status for a rule of version 01-01-03, onlyupper versions like 01-01-04.. of same rule are available to ruleresolution algorithm. Lower version like 01-01-01 and 01-01-02 are notavailable for rule resolution algorithm

FINAL : We need to set availability to Final if we want this rule to be available(equivalent to Yes), but want to prevent others from overriding this rule in anyother RuleSet. A final rule can be superceded by a higher-numbered version (inthe same RuleSet), but not by any version in any different RuleSet.

A rule is said to be available only when its availability is either Yes or Final


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Application Deployment

Create a Rule-Admin-Product instance to create a zip file ofan application and its data instances

Rule-Admin-Product instance allows you to specify in great detail which rules to save

RuleSets (and versions)

Data instances

When rules specify criteria for data instances

Creates a zip file containing rule and data instances to upload into a separate system


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Understand the impact of RuleSet versioning on the deploymentand migration of rules

You can use these tools to copy a product or RuleSet from one Process Commander system to another. (Also calledmigrating or moving, this procedure doesn't alter or delete the source rules.)

For example, you can move a product from a smaller development or test Process Commander system into aproduction Process Commander system. The source and destination systems may have different servers, operatingsystems, database vendors, Web server software vendors and so on. Information inside the ZIP file consistsentirely of XML documents in Unicode characters.

Confirm that you have a working Operator ID with a PegaRULES:SysAdm4 access role on both the source systemand destination system.

Confirm that the Process Commander version number of the destination system is not less than the version numberof the source system. Don't attempt to move a RuleSet created in version 05-01-06 into a system based on version04-02-01.

Review the RuleSets version rules to be included. Note the prerequisite RuleSets and versions they reference. Ifmoving more than one RuleSet, note whether and how they are interdependent.

On the destination system, access the Rules by Type Explorer. Confirm that the destination system includes all theprerequisite RuleSets and versions needed.

On the source system, create a Product rule or Product Patch rule if you need to include data instances or aninstallation activity in the ZIP archive.

On the source system, examine the All Checkouts report to make sure none of the rules to be migrated is checkedout. Choose the View > Rules > All Checkouts menu item to produce this report. On the source system, use Rules per RuleSet, Version, Class report (in the Rule Reports area of the MonitorActivity slice to estimate a count of rules to be included in the ZIP archive. (The reports show only up to 10,000rules. The ZIP archive may contain more than 10,000 rules.)

Export the ZIP archive. Copy the ZIP archive to the destination system. Import the ZIP archive. Adjust your access group as necessary to provide access to the uploaded RuleSets and versions. Log off, then log in with the updated access group, and review the uploaded results. If they are satisfactory, this

may be a good moment to lock the imported RuleSets and versions.

Consider whether a new class group and work type structure is appropriate for deployment of the application.


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Able to port an application and install it to run in parallel withan existing applicationFollowing are the common steps to port an application

1. Save all the rules

2. Make a Rule-Admin-Product

3.Use the import archive tool to import the zip file

Understand and apply the concepts of portability andparallelism


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Application Rule Explain the purpose of application rule

Rule-Application is the place where we specify the RuleSet lists so that this list can be shared acrossmultiple user configurations. This ensures the following benefits:

Reduce the namespace problems

Smaller and efficient caching

A user can have multiple applications.

Allows users to have different privileges across different applications.

Previously though multiple applications are allowed, its only through the mixed ruleset lists i.e., the

Rulesets required are combined as a single long list. So multiple applications coexist in the single

ruleset list.

The PegaRules 5.1 is so developed to adopt the application focused user configuration. Rule-

Application alone remains as the center where we mention the rulesets list, which the user has access

to. If the user works with a particular application, then that particular ruleset list becomes the

pxThreads active ruleset list.

Understand the connection between application rules, Rule Sets andrule resolutionIn the rule resolution process the engine checks for the application rules which are configured in the

access group and also the order in which the rule sets are configured in Rule-Application also important.


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Units of Work Define and understand the differences between the basic

units of work and their associated work classes:Work-Object-

A work object is the primary unit of work completion in an application, and theprimary collection of data that a flow operates on.

As an application is used, work objects are created, updated, and eventuallyclosed (resolved).

Every work object has a unique ID (property pyID), an urgency value, and a status(property pyStatusWork).

Work-Cover- A cover is a work object that is also a parent to one or a few other related work

objects. Typically one work party such as the customer party is present inthe cover work object and also present in all of the covered work objectsassociated with it. The covered work objects are the children in a parent-childrelationship.

Internally, a cover is a work object in a concrete class derived from the Work-Cover- abstract class.

A cover work object provides a means to coordinate processing of the relatedwork objects. Normally, the system resolves a cover work object once all its"member" covered work objects are resolved. The standard ticket rule Work-Cover-.AllCoveredResolved alerts a cover flow that all the member work objectshave been resolved.


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Locking a covered work object normally also locks the cover work object. This is

desirable as the cover work object may contain totals, balances, counts or otherderived information that require single-threaded access. Normally, the cover

work object is added to the clipboard using a page named pyCoverPage; the

covered work object is on a page named pyWorkPage.

The covered work objects may be of various work types. However, the work type

of the cover and the work type of the covered objects must all belong to the

same work pool.

Work-Folder- A folder is a work object in a concrete class that inherits from the Work-Folder-

class. A folder object holds a collection of one or more other work objects (which

themselves may be basic work objects, other folders, or covers) providing access

for analysis and reporting.

By convention, the work object ID of folders has the format F-99999.

In contrast to covers:

One work object may be associated with multiple folders, but only with one

cover.

Members of a folder can belong to various work types, which need not be all in a

single work pool.

The relationships between folder work objects and their contents may be many-

to-many.


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Understand the inheritance structure of workclasses@baseClass

Work-

Cover-

Folder-

Object-

Understand when to inherit from work-object-versus work-cover-

Generally we use Work-Object- inheritance for individual work objects, if we want toprocess multiple dependent work objects which are tightly coupled, covers (work-cover-)

can be used. If the work objects are not tightly coupled then we can use Folders for

resolution of multiple tasks.


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Explain how a work object ID is defined

A work object ID is the permanent, external identifier of a workobject, the value of property Work-.pyID.

Prefixes and suffixes

For every work object, either the prefix or suffix must be present.Normally the system assigns a permanent work object ID automaticallyas a work object is created. The standard utility activity named Work-.GenerateID uses the standard properties pyWorkIDPrefix andpyWorkIDSuffix in its computation.

For example, the prefix of work object Q-1432 is Q. The prefix of thework object MORT-763-K4 is MORT. The suffix of work object 15378-DRis DR.

If you don't specify a prefix, the Work-.GenerateID activity uses W as

the prefix and no suffix. The Work-Cover-.GenerateID activity uses Cas the default prefix. Conventionally, the F prefix identifies folderwork objects.

The internal class Data-UniqueID supports work object numbering, andensures that work object IDs are unique system-wide, not just withinan application or organization.


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Describe how flow execution moves between awork object and its cover during processingWhen the flow belongs to class which inherits form Work-Cover- Cover related data can be

seen in pyWorkPage.

When the flow belongs to Covered class, Cover related information can be seen in

pyWOrkCover and CoveredWork can be seen in pyWorkPage

Locate Work objects and covers on the clipboard


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Wizards and Accelerators Understand the purpose and output of external setup wizard

An optional step during installation or upgrade of a Process Commander system,the External Setup wizard creates a starter kit of rules and data instances based

on a single input text value.

Ordinarily, the External Setup wizard is not started from within the Process

Commander portal.

For example, if the installer enters Alpha, the External Setup wizard creates

these instances:

A RuleSet named Alpha and a Version 01-01-01

An organization Alpha.com, a division AlphaDiv in the organization, and a unit

AlphaUnit within the division

A top-level abstract class Alpha- referenced in the Organization data instance

An application rule AlphaApp

A workbasket named [email protected]

A work group named [email protected]

An Operator ID named [email protected], linked to the Developer portal

and the application rule.


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Understand what needs to be created prior to andafter running the Application Accelerator inadvanced mode

Pre Application Accelerator set up

Create Rule Sets

Add new Rule Sets to application ruleReset your Ruleset Access

Create new classes

Post-Accelerator manual Entry

Complete Set up of your application

Create RuleSet and RuleSet versions

Create classes

Add new class group to work classes


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Understand the purpose and output of theApplication Accelerator when run in advancedmode

Streamlines the process of setting up the foundation for your application

Guides you through the initial development steps when you construct a newapplication

Allows you to build the elements of your application from the Class Group downApplication Accelerator Creates

A RuleSet and version for the application which is added to your access group

A simple class structure, including covers and work-related classes

A class group (work pool) and supporting database table

Work object and cover prefixes

Properties and models

Work parties

Work object forms (harness and section rules) with your application propertiesadded

One or more basic flows

Workbaskets, worklists, and work groups


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Application Guardrails Identify the guard rails and describe their intent Adopt an Iterative Approach

Establish a Robust Foundation

Do Nothing That Is Hard

Limit Custom Java

Build For Change

Design Intent-Driven Processes

Create Easy-To-Read Flows

Monitor Performance Regularly

Calculate and Edit Declaratively, Not Procedurally

Keep Security Object-Oriented Too


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Know how to validate guardrail compliancewhen building an application The Application Preflight tool performs a number of checks on the rules in

the currently selected application. These checks are designed to encourage good

design and implementation practice, such as codified in the SmartBuild

guardrails and elsewhere.

A rule in your application may work correctly and save without errors, but stillbe marked with a warning (). The Application Preflight tool summarizes these

warnings.

For example, a decision table rule may contain two rows that conflict give a

different result for the same inputs. You can save the rule and execute it within

your application, because the uppermost row of the table is used at runtime,

and other conflicting rules are ignored. However, the conflict may indicate that

the rule was not entered correctly.

You may perform the preflight check at any time during development. As a best

practice, use the preflight tool before locking a version of a RuleSet, and

research each warning message.

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01 Class Structures and Hierarchy Design

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