[OFBiz] SVN: r4712 - in trunk/website: . docs

jonesde at svn.ofbiz.org jonesde at svn.ofbiz.org
Fri Mar 25 21:58:05 EST 2005 

Author: jonesde
Date: 2005-03-25 20:58:01 -0600 (Fri, 25 Mar 2005)
New Revision: 4712

Removed:
   trunk/website/docs/rules.html
Modified:
   trunk/website/documents.html
Log:
Removed more rule engine references

Deleted: trunk/website/docs/rules.html
===================================================================
--- trunk/website/docs/rules.html	2005-03-26 02:45:03 UTC (rev 4711)
+++ trunk/website/docs/rules.html	2005-03-26 02:58:01 UTC (rev 4712)
@@ -1,224 +0,0 @@
-<html>
-<head>
-<title>The Open For Business Project: Rule Engine Guide</title>
-</head>
-<body>
-
-<table width='100%'>
-  <tr>
-    <td width='50%' align='left' valign='center'>
-        <a href="http://www.ofbiz.org"><img src="http://www.ofbiz.org/images/ofbiz_logo.jpg"  border="0" alt='The Open For Business Project'/></a>
-    </td>
-    <td width='50%' align='right' valign='center'>
-        <a href="http://sf.net/projects/ofbiz"><img src="http://sourceforge.net/sflogo.php?group_id=27173" width="88" height="31" border="0" alt="SourceForge Logo"/></a> 
-        <a href="http://www.ofbiz.org"><img src="http://www.ofbiz.org/images/ofbiz_powered.gif" width="88" border="0"/></a>
-    </td>
-  </tr>
-</table>
-<hr class="sepbar"/>
-
-<h2 align="center">The Open For Business Project: Rule Engine Guide</h2>
- 
-<div class='contenttext'>Written By: David E. Jones, <a href="mailto:jonesde at ofbiz.org">jonesde at ofbiz.org</a></div>
-<div class='contenttext'>Last Updated: 15 March 2002</div>
-<!-- $Id$ -->
-
-<hr class="sepbar"/>
-<h3>Table of Contents</h3>
-
-<ul>
-  <li><a href="#Related_Documents">Related Documents</a></li>
-  <li><a href="#Introduction">Introduction</a></li>
-  <li><a href="#UIs">Rule Engine UIs</a></li>
-  <li><a href="#Logikus">Logikus Language</a></li>
-  <li><a href="#RuleML">RuleML Language</a></li>
-  <li><a href="#API:Logikus">API: Logikus Facade</a></li>
-</ul>
-
-<hr class="sepbar"/>
-
-<h3><a name="Related_Documents">Related Documents:</a></h3>
-<hr class="sepbar"/>
-<ul>
-  <li><a href="../documents.html#JavaDocs">JavaDoc List (Documents Page)</a></li>
-  <li><a href="coreconfig.html">Core Configuration Guide</a></li>
-</ul>
-
-<hr class="sepbar"/>
-<h3><a name="Introduction">Introduction</a></h3>
-<hr class="sepbar"/>
-<p class='contenttext'>The OFBiz Rule Engine is based on logic programming technologies that have existed for
-various decades. The most notable logic programming language is Prolog, although others do
-exist. Since the invention of Prolog many variations on the theme have appeared, and many
-exist now as business rule engines, constraint based optimization engine, etc.</p>
-
-<p class='contenttext'>Some products in the market for Java compatible logic engines and variants include ILOG JRules and various
-other rule and constraint technologies (www.ilog.com), Blaze Advisor (www.blazesoft.com) 
-and YASU Tech QuickRules (www.yasutech.com). There are also a number of open source and 
-research efforts in place, most notable JESS from some guys at the Sandia National Labs. Two
-open source projects on SourceForge that deserve mention are under the projects names drools
-and info-sapient. Other interesting open source projects include Mandarax, and ...</p>
-
-<p class='contenttext'>The basic idea behind a rule or logic language is that rather than specifying a set
-of instructions to run in a certain order like traditional imperative languages you specify
-facts and rules. A rule is simply an assertion with preconditions. If all of the preconditions
-are met then the assertion is added to the base of known facts, or the knowledge base. A
-fact is really just a rule with no preconditions so the assertion is always added to the
-knowledge base.</p>
-
-<p class='contenttext'>The ruleset can be used in two different ways: forward chained and backward chained. Backward
-chaining is the original way that logic languages, including Prolog, operated. The popularity
-of forward chaining has increased over the years and is now more commonly referred to and 
-requested than backward chaining. The method of using a ruleset you choose will really depend 
-more on what you are trying to do than with the popularity of the options as different 
-applications are more suited to one or the other.</p>
-
-<p class='contenttext'>Backward chaining involves a ruleset and a query. The query is the exact opposite of a fact, 
-it is a rule with no assertions, just a set of preconditions. When the query is run against the 
-ruleset the rule engine simply either proves the query as true or false, or it finds the facts
-that satisfy the constraints of the query. This can be very useful for constraint based searching
-and facts can be produced one at a time rather than waiting for all possible facts to be produced.
-Applying a fitness metric to the resulting facts can help in evaluating the facts and iteratively
-searching as long as desired to find better and better results.</p>
-
-<p class='contenttext'>Forward chaining is a completely different way of using a ruleset. Rather than specifying a query
-to evaluate you simply run the ruleset against the current knowledge base, allowing it to assert
-the facts for each rule has it's preconditions satisfied. This is generally done iteratively until
-no rules have all of their preconditions satisfied. In other words, if a new fact is added to the
-knowledge base that suddenly makes all of the preconditions of another rule true, then that rule
-will also have it's assertion or postcondition added to the knowledge base.</p>
-
-<p class='contenttext'>To make things more interesting, rather than just dealing with the testing and assertion of facts 
-integration with other programs can be done through sensors and effectors. This is basicly the process
-of specifying a method to call that will produce data when the fact is tested for a sensor, or specifying
-a method that will receive data when the fact is asserted for an effector.</p>
-
-<p class='contenttext'>In the current incarnation of the OFBiz Rule Engine only backward chaining is supported.</p>
-
-<p class='contenttext'>On top of the Rule Engine a method is needed of asserting facts and defining rules. If you
-are working directly with the API of the Rule Engine then these objects can be added that way.
-That can be useful for some circumstances, but would be REALLY tedious if it were the only way
-to create facts and rules. A much preferred method is to create a language for specifying facts
-and rules in a text file. There are two major types of these languages right now. One type is
-a free form language like Prolog (which Logikus is based on) and the other type is using an
-XML file. There is a standard in progress for XML rule files called RuleML. Both Logikus and RuleML
-are discussed below.</p>
-
-<p class='contenttext'>An introduction to the OFBiz Rule Engine could not be complete without acknowledging the source
-of the original code base of the Rule Engine and the Logikus language. Even the name Logikus came
-from this source. It is based on the work done for the book Building Parsers in Java by Steven John
-Metsker, published by Addison Wesley. Mr. Metsker wrote the license to the code to be very open,
-similar to the OFBiz license. He basicly said that you can do whatever you want with it as long
-as you don't claim you wrote it. So, I repackaged the code as part of OFBiz and acknowledged him as
-the original author of the code and put a dual copyright at the top of each file from the book.
-I would like to express thanks here to Steven Metsker for creating an excellent book and a nice
-code base that has helped us a lot in getting started. I recomment the book to anyone who plans to
-seriously use or extend the OFBiz Rule Engine.</p>
-
-<hr class='sepbar'/>
-<h3><a name="UIs">Rule Engine UIs</a></h3>
-<hr class='sepbar'/>
-<p class='contenttext'>In addition to using rulesets inside a program they can be run and tested through two user
-interfaces that exist as part of the Rule Engine. The first of these is a JSP in the WebTools
-webapp that has a textarea for the ruleset and an input box for the query. There is a link to
-this page from the main page of the WebTools app.</p>
-
-<p class='contenttext'>The other user interface is a Java Swing application. This looks very similar to the JSP and
-can be run with the following command: <code>java -cp $CLASSPATH:ofbcore-rules.jar org.ofbiz.rules.LogikusIde</code></p>
-
-<hr class='sepbar'/>
-<h3><a name="Logikus">Logikus Language</a></h3>
-<hr class='sepbar'/>
-<p class='contenttext'>The Logikus Language is described very well in Steven Metsker's book Building Parsers in Java.
-It is based on the Prolog syntax, for those who are familiar with that.</p>
-
-<p class='contenttext'>There have been some changes made to Logikus as part of the OFBiz extensions to the language.
-The most notable of these changes is that functors and variables can be upper case or lower case.
-String constants must be enclosed in double quotes to differentiate between them and variables. This
-is different than traditional Prolog and the original Logikus where a word with a lower case first 
-letter is interpreted as a constant instead of a variable name. This change was made to make using 
-the language easier on Java developers, or developers familiar with most imperative languages.</p>
-
-<p class='contenttext'>Other changes in the future will include a syntax for specifying that a function corresponds to
-an entity from the Entity Engine, and for using sensors and effectors.</p>
-
-<p class='contenttext'>There are many examples of Logikus rulesets and queries in the core/docs/examples/rules directory.</p>
-
-<hr class='sepbar'/>
-<h3><a name="RuleML">RuleML Language</a></h3>
-<hr class='sepbar'/>
-<p class='contenttext'>RuleML is an XML file type definition for specifying facts and rules. The website for RuleML
-contains links to many interesting resources and has some interesting information about rule and logic
-languages and their applications. The RuleML website is at 
-<a href="http://www.dfki.uni-kl.de/ruleml/">http://www.dfki.uni-kl.de/ruleml/</a>.</p>
-
-<p class='contenttext'>An interesting open source project to look at to understand RuleML better is Mandarax. They have a 
-RuleML interpreter and a Swing app for editing rules.</p>
-
-<p class='contenttext'>The RuleML interpreter for the OFBiz Rule Engine has not yet been written, but it is planned for.</p>
-
-<hr class='sepbar'/>
-<h3><a name="API:Logikus">API: Logikus Facade &amp; Engine Classes</a></h3>
-<hr class='sepbar'/>
-<p class='contenttext'>To use Logikus rulesets and queries from your Java applications you can use the LogikusFacade
-class which provides some useful methods for parsing and executing rulesets, and then retrieving
-and evaluating the results. The full path of the class is org.ofbiz.rules.logikus.LogikusFacade.</p>
-
-<p class='contenttext'>I will go through an example in here of parsing a Logikus file to create a Program class, and
-parsing a query to make a Query class, and then optionally adding rules or facts to the Program,
-and then running the Query against the Program and retrieving the results. This is a backward 
-chaining example.</p>
-
-<p class='contenttext'>First, the main packages you will deal with are:</p>
-<ul>
-  <li>org.ofbiz.rules.logikus.*</li>
-  <li>org.ofbiz.rules.parse.*</li>
-  <li>org.ofbiz.rules.parse.tokens.*</li>
-  <li>org.ofbiz.rules.engine.*</li>
-</ul>
-
-<p class='contenttext'>Next, create a <code>org.ofbiz.rules.engine.Program</code> object from a logikus ruleset
-by parsing the text of the ruleset with the following instruction:</p>
-<p class='contenttext'><code>Program program = LogikusFacade.program(programText);</code></p>
-<p class='contenttext'>Before parsing the query text and creating a Query object you can add other
-facts and rules to the program with the following method:</p>
-<p class='contenttext'><code>program.addAxiom(axiom);</code></p>
-
-<p class='contenttext'>Both the Fact object and Rule object implement the Axiom interface and can
-be added to a program as an axiom. For instructions on how to construct these
-objects see the JavaDocs for them. They are both in the <code>org.ofbiz.rules.engine</code> package.</p>
-
-<p class='contenttext'>Now you can parse the query text and create a Query object with the following:</p>
-<p class='contenttext'><code>Query query = LogikusFacade.query(queryText, program);</code></p>
-
-<p class='contenttext'>Now everything is in place to get the engine running and finding results. The
-Query object has a method to get a pointer to the current set of variables that
-represent a result to the query. This object will always contain the current
-result from the query.</p>
-<p class='contenttext'><code>Unification vars = query.variables();</code></p>
-
-<p class='contenttext'>It works like the Enumeration class in that the variables can be used a number 
-of times for a single result and the next result will be retrieved when the 
-<code>canFindNextProof()</code> method is called, as follows:</p>
-<p class='contenttext'><code>boolean moreProofs = query.canFindNextProof();</code></p>
-<p class='contenttext'>or, maybe in a bit more useful form:</p>
-<p class='contenttext'><code>while (query.canFindNextProof()) {</code></p>
-
-<p class='contenttext'>The individual results can be retrieved from the Unification object if variables
-where specified in the query. If no variables where specified in the query the
-<code>canFindNextProof()</code> will return true, but the <code>vars.size()</code>
-method will return 0. This means that a proof was found, or the query was proved 
-to be true, but no variables needed unifying.</p>
-
-<p class='contenttext'>When variables are unified in the result they can be retrieved from the 
-Unification with the following code:</p>
-<p class='contenttext'><code>Variable var = vars.variableAt(i);</code></p>
-<p class='contenttext'>or an enumeration of the variables can be pulled out as follows:</p>
-<p class='contenttext'><code>Enumeration varEnum = vars.elements();</code></p>
-
-<p class='contenttext'>The Variable and Unification objects have <code>toString()</code> methods
-for displaying their values. Other information about them is available in the
-JavaDocs.</p>
-
-</body>
-</html>

Modified: trunk/website/documents.html
===================================================================
--- trunk/website/documents.html	2005-03-26 02:45:03 UTC (rev 4711)
+++ trunk/website/documents.html	2005-03-26 02:58:01 UTC (rev 4712)
@@ -200,7 +200,6 @@
     <li class='contenttext'><a href="docs/entity.html">Entity Engine Guide</a></li>
     <li class='contenttext'><a href="docs/services.html">Service Engine Guide</a></li>
     <li class='contenttext'><a href="docs/workflow.html">Workflow Engine Guide</a></li>
-    <li class='contenttext'><a href="docs/rules.html">Rule Engine Guide</a></li>
     <li class='contenttext'><a href="docs/datafile.html">Data File Guide</a></li>
     <li class='contenttext'><a href="docs/minilang.html">Mini-Languages Guide</a></li>
     <li class='contenttext'><a href="docs/control.html">Control Servlet Guide</a></li>
@@ -226,7 +225,6 @@
     <li class='contenttext'><a href="api/framework/guiapp/build/javadocs/index.html">GUI Application API</a></li>
     <li class='contenttext'><a href="api/framework/minerva/build/javadocs/index.html">Minerva Connection Pool API</a></li>
     <li class='contenttext'><a href="api/framework/minilang/build/javadocs/index.html">MiniLang (Simple Method) API</a></li>
-    <li class='contenttext'><a href="api/framework/rules/build/javadocs/index.html">Rules Engine API</a></li>
     <li class='contenttext'><a href="api/framework/security/build/javadocs/index.html">Security API</a></li>
     <li class='contenttext'><a href="api/framework/service/build/javadocs/index.html">Service Engine API</a></li>
     <li class='contenttext'><a href="api/framework/shark/build/javadocs/index.html">Shark (Embedded) API</a></li>

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