1. - L A K S H M I P R A T Y U S H A K U P P A
DROOLS
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2. CONTEXT
• Java enterprise level application can be split into
three parts −
• User Interface
• Service layer
• Business layer
• Drool is a standard way to handle the business
layer.
• It is a collection of tools that separates logic and
data within business processes.
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3. WHAT IS DROOLS ?
• Drools is a Business Logic integration Platform (BLiP).
• It is written in Java.
• It is an open source project that is backed by JBoss
and Red Hat, Inc.
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4. ADVANTAGES
• Declarative Programming
• Rules are written in less complex language.
• Speed and Scalability
• One can add new rules without having to modify the
existing rules and these are very quickly processed.
• Centralization of Knowledge
• By using Rules, you create a repository of knowledge (a
knowledge base) which is executable.
• Tool Integration
• Tools such as Eclipse provide ways to edit and manage rules
and get immediate feedback, validation, and content
assistance.
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5. KNOWLEDGE BASE
• Interface that manages a collection of rules,
processes, and internal type.
• The main purpose of Knowledge Base is to store
and reuse them because their creation is
expensive.
• Knowledge Base provides methods for creating
knowledge sessions.
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6. KNOWLEDGE SESSIONS
• It is the main interface for interacting with the Drools
Engine.
• The knowledge session can be of two types:
• Stateless Knowledge Session
• Stateful Knowledge Session.
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7. STATELESS KNOWLEDGE SESSION
• It is a stateless session that forms the simplest use case, not
utilizing inference.
• It can be called like a function, passing it some data and then
receiving some results back.
• Examples:
• Validation
• Is this person eligible for a mortgage?
• Calculation
• Compute a mortgage premium.
• Routing and Filtering
• Filter incoming messages, such as emails, into folders.
• Send incoming messages to a destination
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8. STATEFUL KNOWLEDGE SESSION
• Stateful sessions are longer lived and allow iterative
changes over time.
• Some common use cases for Stateful sessions
include:
• Monitoring
• Stock market monitoring and analysis for semi-automatic buying.
• Diagnostics
• Fault finding, medical diagnostics
• Logistics
• Parcel tracking and delivery provisioning
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9. KNOWLEDGE BUILDER
• The interface is responsible for building a
KnowledgePackage from knowledge definitions
(rules, processes, types).
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10. EXAMPLE
The objects that the rule
file accesses should be
added to the session.
A kmodule.xml file
defining in a
declaratively way
the KieBases
and KieSessions that can
be created from it.
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