IBM BPM - Business Objects and Variables in IBM Process Designer

Introduction

In Process Designer, variables capture the business data that is used by activities in a business process definition or by steps in services such as integration services or human services. Each variable has its own type and scope. All variables you create must be declared before you can start using them.

Variable types in Process Designer

You can use the variable types provided by the system toolkits, such as the System Data toolkit, or you can create custom business objects, depending on the requirements of the business data included in your process.

During Process Designer installation, the system toolkits are imported into the Process Center repository so that each process application and toolkit that you create has access to a common system data. The system toolkits provide the following categories of variables:

Base Types

Base types allow you to create custom variable types called business object. A list of all the base types is provided further in this topic.

System Types

System types are provided variable types that cannot be modified. A list of all the system types is provided in the JavaScript API reference guide.

Table 1. Provided base types
Base types	Description
String	Allows alpha-numeric characters to be entered into the variable.
Integer	Accepts digits without a decimal place, such as 45 or 20.
Decimal	Accepts digits with up to two decimal places, such as 45.3 or 20.13.
Date	Allows date and time formats to be entered into the variable.
Time	Allows date formats to be entered into the variable as times. The user enters a time, and before the variable is entered into the symbol table, it is converted to and behaves like a date.
Selection	Allows you to provide a list of possible entries to a user, of which the user can select only one. A selection is a list of different values; each value is typed as a string. A selection variable appears at run time on a Coach form as a drop-down list or as radio buttons.
Boolean	Accepts either true or false as values. It appears at run time on a Coach form as a check box.
Structure	To use a structure type, you need to create a custom structure type and define its properties. A structure regroups business data that is related to the same subject. For example, a Customer structure might contain elements such as lastName, firstName, homeNumber, streetAddress.

Custom Variable Types

Custom variable types are defined using business objects. If the predefined business objects provided in the system toolkits do not represent your needs, you can create your own business objects.

Variable Scope in Process Designer

In IBM® BPM, all variables declared for a business process definition (BPD) or service are local variables.

Local variables are only accessible to the currently executing process instance or service. Because variables are unique to an individual BPD or service, you can use a variable of the same name in a nested BPD or service and there are no conflicts at run time.

Table 1. Available namespaces
Namespace	Description
tw	Top-level Process Designer namespace
tw.object	Access Process Designer JavaScript objects and business objects (variable types)
tw.local	Access and update BPD and service-level variables
tw.system	Access system features and functionality
tw.system.org	Access security functionality
tw.epv	Access exposed process values (EPVs)
tw.env	Access environment variables

Initializing Complex Variables and Lists

Before using a complex variable, initialize it by using a script like the following:

If the variable is a complex object

tw.local.<variableName>=new tw.object.<businessObject>();

Example:

tw.local.customer=new tw.object.CustomerBO ();

If the variable is a list, use: tw.local.<listName>=new tw.object.listOf.<businessObject>();

Example:

tw.local.customerList= new tw.object.listOf. CustomerBO ();

Assigning Data to Object

tw.local.customer.id = “C123”

tw.local.customer.name = “BlueMix”

Conclusion

In IBM Process Designer, we can create a custom business object by using a base business object or by defining a new complex structure. When you create a business object in a process application, that object is available for all business processes, case types, and services in the process application. If you want to share a custom business object across process applications, create or store the custom object in a toolkit. Then, create a dependency on that toolkit from the process applications that require the variable. We have learnt how to create Business Object and Initialization of Business Object.

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