PRPC for Java developers — Concepts and terms

PRPC is a Java server application. It employs a standard relational database hosted by Oracle, IBM DB2, or Microsoft SQL Server to store rules, data, and other persistent objects.

PRPC provides the run-anywhere, inheritance, memory management, multithreading, scalability, and encapsulation benefits of Java to business rules and business process management (BPM) applications. Integrating PRPC with Java EE and EJB applications, JMS, SOAP/XML, and other new technologies is simpler because of its Java foundation.

The servlets that make up PRPC are designed to run with the Apache Tomcat servlet implementation or with commercial Web application servers such as IBM WebSphere and Oracle WebLogic (formerly BEA Systems). Consult other documents for exact platform, database, and server support.

To create a PRPC application (a set of rules grouped into one or a few rulesets) business analysts and other developers create and update forms to define the rules, rather than writing Java source code. This approach improves developer productivity, program modularity, and maintainability.

Using rule forms enables less technical people to work with familiar "objects" rather than learn a new language or syntax. When PRPC accesses rules to execute them, it assembles executable Java code.

The PRPC clipboard is a hierarchically structured temporary Java object for holding and naming property values for a user session. The clipboard data structure is known as a page, which can contain embedded pages that in turn may contain embedded pages. Names of properties on the clipboard use the page names as prefixes, following Java dot notation conventions, such as:

MortgageApplication.Signer(2).Address(3).StateCode

Property values on the clipboard are UNICODE-based Java objects. When PRPC sends a Single Value property (corresponding to the java.lang.String class) using HTTP, the value is transmitted using the UTF-8 character encoding. When PRPC saves a clipboard page, the database, key, and many other (non-array) properties each become a database column.

For several rule types, you can review an example of the Java code that PRPC generates after you save a form, by clicking View Java from the Actions menu. (This generated Java is not exactly the Java that is compiled and executed at runtime, as additional rules may be inlined to improve performance.) Such generated Java source code is read-only.

See:

About Activity rules About Access When rules About Case Match rules About Correspondence rules About Correspondence Fragment rules About Declare Expressions rules About Declare Trigger rules About Decision Tables About Decision Trees About Edit Input rules About Edit Validate rules

About Flows About Flow Actions About Harnesses About HTML rules About HTML Fragment rules About Control rules About Data Transforms About Map Values About Parse XML rules About Sections About Summary View rules About Validation rules About When Condition rules About XML rules

In a few cases, you can enter Java source code directly into rule forms. See:

• About Edit Input rules
• About Function rules
• Using Java in an activity step
• Java directive in source HTML

To speed your Java entry, you can register your preferred Java IDE and editor with PRPC. Use it on your workstation to edit, search, syntax-check, and format the source code. Then upload the code to the PRPC server as part of a rule. See How to set up a Java development environment.

Like the system-generated Java, your Java code can call on a large documented Application Programmer Interface known as the PublicAPI.

For more information about generated Java, see the PDN article Reviewing generated Java code.

The following table may help you relate PRPC terms to similar Java terms. These are analogies, not exact correspondences.

PRPC term	Rule type	Similar Java, XML, or database concepts
expressions	-	Java expressions
data transforms	Rule-Obj-Model	initializers, constructors
activities	Rule-Obj-Activity	public Java instance methods with a void return type
method	Rule-Method	system-supplied stored procedure
properties	Rule-Obj-Property	instance variables
Single Value property		Java String object
rule resolution		inheritance
property of mode Page List		repeating group
overridden rule		overloaded method
When condition rule	Rule-Obj-When	if statement
decision tree	Rule-Declare-DecisionTree	nested if statement
Type for Value mode properties		primitive data types. Most Java primitive data types are available as PRPC Types.
primary page of an activity		this keywordA word that, in certain circumstances, has a specific meaning to PRPC. Keywords are sometimes called "reserved words."
ultimate base class	@baseclass	Object class — topmost class
Value Group property mode		HashMap