What are the Rule engines in Java ?

Jess Rule Engine

• Fastest
• Scripting environment written in Java
• can manipulate and reason Java objects

JBoss Drools

• Open source
• Object-Oriented
• Declarative logic programming
• Flexible
• High performance execution

Termware 

• Term Processing System
• Better cost effective
• comes with Java debug interface
• includes computational algebra systems, formal models analysis and transformation

Hammurapi Rules

• simplifies complex problems into smaller steps
• No need to learn specialized rules language
• Rules and facts are written in Java
• Same rules and rulesets can be applied or forward or backward chaining 

Open Rules 

• Less expensive and Easier to develop
• Full-scale, open source Business Rules management framework
• Create, deploy, execute, and maintain decision services
• can meet the increasing demand for complex rulebases and high-transaction volumes
• User-friendly Rules Administrator that utilizes the power of MS Excel and Eclipse

 

JRuleEngine 

• Open source
• based on Java Specification
• Rules can be loaded by an XML file or JRuleEngine APIs, so rules can be stored externally into a database 
• It's distribution consists of a JAR library, source, examples and javadoc

SweetRules

• Integrated toolkit for semantic web rules
• based on RuleML (Rule Markup Language)
• supports Logic programs extension of RuleML
• can prioritize Conflict handling and procedural attachments for actions and tests

Blaze Advisor

• used by Sun Microsystems
• can verify the rules and procedural logic

JxBRE

• Light-weight BRE (Business Rules Engine) for controlling the process flow for an application
• uses XML to control the application

JEOPS 

• A forward chaining Rule engine
• can define rules in Java Application servers, Client apps and Servlets
• Declarative programming.

OFBiz Rule Engine

• Backward chaining is supported

JSL : Java Search Library 

• Library written in Java
• provides a framework for general searching on graphs
• Standard search algorithms depth-first, breadth-first and A* are provided

Mandarax 

• Based on backward reasoning
• Easy integration of all kinds of data sources
  E.g., database records can be easily integrated as sets of facts

Algernon 

• Efficient and concise KB traversal and retrieval
• Straightforward access to ontology classes and instances
• Supports both forward and backward chaining

TyRuBa 

• supports higher order logic programming : variables and compound terms are allowed everywhere in queries and rules
• speeds up execution by making specialized copies of the rule-base
• builds an index for fast access to rules and facts in the rule base.
  The indexing techniques works also for higher-order logic.
  TyRuBa does 'tabling' of query results.

JLog 

• An implementation of a Prolog interpreter, written in Java
• BSF-compatible language
• It includes built-in source editor, query panels, online help, animation primitives, and a GUI debugger

JTP (Java Theorem Prover)

• based on a very simple and general reasoning architecture
• Easy to extend the system by adding new reasoning modules (reasoners), or by customizing or rearranging existing ones

InfoSapient 

• Semantics of business rules expressed

RDFExpert RDF - Driven expert system shell

• It uses Brian McBride's JENA API and parser.
• A simple expert system shell that uses RDF for all of its input : knowledge base, inference rules and elements of the resolution strategy employed.
• It supports forward and backward chaining.

Jena 2 

• Java framework for writing Semantic Web applications
• It has a reasoner subsystem which includes a generic rule based inference engine together with configured rule sets 
• The subsystem is designed to be extensible so that it should be possible to plug a range of external reasoners into Jena

JLisa

• Powerful framework for building business rules accessible to Java
• JLisa is more powerful than Clips because it has the expanded benefit of having all the features from common LISP available.

Euler 

• A backward-chaining reasoner enhanced with Euler path detection

Pellet OWL Reasoner

• Open-source Java based OWL DL reasoner
• It can be used in conjunction with either Jena or OWL API libraries
• provides functionalities to see the species validation, check consistency of ontologies, classify the taxonomy, check entailments and answer a subset of RDQL queries
• based on the tableaux algorithms developed for expressive Description Logics

Prova 

• It extends Mandarax by providing a proper language syntax, native syntax integration with Java, and agent messaging and reaction rules.
• The language is used as a rules-based backbone for distributed web applications in biomedical data integration.

JShop2

• Simple Hierarchical Ordered Planner (SHOP) written in Java
• Domain-independent automated-planning systems
• based on ordered task decomposition, which is a type of Hierarchical Task Network (HTN) planning
• uses a new "planner compilation" technique to achieve faster execution speed

OpenLexicon 

• Business rules and business process management tool
• rapidly develops applications for transaction and process-based applications
• 2 main components of Lexicon: the metadata repository and the business rules engine 
• can evaluate small, in-line Java expressions.

MINS Reasoner

• Mins Is Not Silri
• A reasoner for Datalog programs with negation and function symbols
• supports the Well-Founded Semantics

Zilonis

• An extremely efficient, multithreaded Rules engine based on a variation of the forward chainning Rete algorithm.
• can define a scope for a user or group of users with inheritance of rules between them
• The rules language is similar to CLIPS

JCHR

• An embedding of Constraint Handling Rules (CHR) in Java
• The multi-paradigmatic integration of declarative, forward chaining CHR rules and constraint (logic) programming within the imperative, OO host language
• High performance is achieved through an optimized compilation to Java code.
• suited for the high-level development of expert systems, incremental constraint solvers and constraint-based algorithms

Esper

• enables rapid development that process large volumes of incoming messages or events
• supports Event Stream Processing : Time-based, interval-based, length-based and sorted windows; Grouping, aggregation, sorting, filtering and merging of event streams; SQL-like query language using insert into, select, from, where, group-by, having and order-by clauses; Inner-joins and outer joins (left, right, full)  
• filters and analyzes events in various ways, and responds to conditions of interest in real-time

mProlog

• Sub-product of the 3APL-M project
• It delivers a reduced Prolog engine, optimized for J2ME applications.
• The 3APL-M project is a platform for building applications using Artificial Autonomous Agents Programming Language (3APL) as the enabling logic for the deliberation cycles and internal knowledge representation.

OpenL Tablets

• Create Decision Tables in Excel and use them in Java application in a convenient type-safe manner.
• Use Data Tables in Excel for data setup and testing
• Eclipse plugin controls validity of Excel tables

Jamocha 

• Rule engine and expert system shell environment
• comes with a FIPA-compliant agent
• The agent is based on the Multiagent System JADE that supports speech-acts and the FIPA agent interaction protocol.