New and noteworthy

Drools 2.5 contains a mouthful of fixes and enhancements, mostly evolutionary. One big change is the use of Apache JCI as the compiler interface for Java and Groovy semantics (and using Eclipse JDT as the runtime Java semantic compiler by default). This is a key milestone on the way to Drools 3.

There are some performance enhancements, and there has been excellent support from the community in nailing down bugs, issues and providing fixes and enhancements.

Release Notes - drools - Version 2.5

New and Noteworthy

  <rule name="test rule" xor-group="group" >
  ...

WorkingMemory workingMemory = new SynchronizedWorkingMemory( ruleBase.newWorkingMemory( ) );

ChangeLog

• Bug
  • DROOLS-294 - WorkingMemory synchronization is not complete (Barry Kaplan)
  • DROOLS-314 - MethodMetadataSource's need a stopping Class (Barry Kaplan)
  • DROOLS-318 - WorkingMemoryEventListenerProcessor implements wrong interface (Barry Kaplan)
  • DROOLS-347 - Maven build of drools-spring-jdk5 fails on Mac OS X (Andy Barnett)
  • DROOLS-367 - Wrong rule executed when modifying object in workingmemory (Michael Neale)
  • DROOLS-374 - Caching of classloaders in causes problems with hot deployment in some J2EE containers (Michael Neale)
  • DROOLS-376 - Make source file (c) headers consistent with codehaus (Michael Neale)
  • DROOLS-386 - Bug with the Escalation example? (Robert Laflamme)
  • DROOLS-401 - Missing semaphore types in schema file (rules.xsd) (Edson Tirelli)
  • DROOLS-403 - no-loop incorrectly removes all instances of a rule from the agenda (Michael Neale)
  • DROOLS-409 - rename getNoLoop to isNoLoop to obey JavaBean naming convention (Mark Proctor)

• New Feature
  • DROOLS-303 - Default rule-method parameter annotation (Barry Kaplan)
  • DROOLS-360 - Maven goal for drools-all-src-XXX.zip (Mark Proctor)
  • DROOLS-361 - Auto add RuleSet to RuleBase (Barry Kaplan)
  • DROOLS-363 - Decision tables in spreadsheets (Michael Neale)
  • DROOLS-383 - Integrate java:functions feature in decision tables. (Michael Neale)
  • DROOLS-388 - Support for application data (variables), per rule duration, salience and names (Ricardo Rojas)
  • DROOLS-408 - Xor Group so only one rule can fire for a specific group (Mark Proctor)

• Improvement
  • DROOLS-296 - Allow for default id value in parameter annotations (Barry Kaplan)
  • DROOLS-297 - Allow multiple consequence annotations per rule (Barry Kaplan)
  • DROOLS-301 - Remove 'Drools' prefix from annotations (Barry Kaplan)
  • DROOLS-309 - MethodMetadataSource to ignore certain classes (Barry Kaplan)
  • DROOLS-310 - Condition sharing for POJO rules (Peter Royal)
  • DROOLS-348 - JDK 1.3 no longer supported (Barry Kaplan)
  • DROOLS-350 - Utilize 1.4 nested exceptions (Barry Kaplan)
  • DROOLS-357 - Packaging between factory and meta needs some attention (Barry Kaplan)
  • DROOLS-364 - Update spring libs and config files for 1.2 (Barry Kaplan)
  • DROOLS-372 - Update Groovy to JSR-03 (Mark Proctor)
  • DROOLS-381 - Add object-condition tests to RuleBuilderTest (Barry Kaplan)
  • DROOLS-387 - add ability for a DSL to acces the XML namespace information in a Configuration (James Strachan)
  • DROOLS-402 - Refactor maven.xml and drools:dist to make it faster and more intelligent (Mark Proctor)
  • DROOLS-410 - Update Janino to 2.3.8 (Mark Proctor)

• Test
  • DROOLS-346 - Ant build.xml doesn't run drools-jsr94 unit tests (Andy Barnett)

• Task
  • DROOLS-351 - Remove drools-annotation and derivitives from 2.1 (Barry Kaplan)
  • DROOLS-370 - Add in drools-decisiontables subproject (Michael Neale)

Release Overview

Small updates to documentation, nothing else.

ChangeLog Highlights:

• Task
  • DROOLS-89 - Update docs on SMF module (Mark Proctor)
  • DROOLS-91 - Document Python Semantics Module (Mark Proctor)

Release Overview

Minor tidyup changes to the build environment and some small improvements to the exception swallowing.

ChangeLog Highlights:

• Improvement
  • DROOLS-349 - Compile problems are "swallowed" by drools (Mark Proctor)
  • DROOLS-353 - Cleanup Maven build (Mark Proctor)

Release Overview

I'm particularly proud of this release, not just because of the large number of fixes and enhancements that make Drools better than ever but because of the momentum Drools is finally gaining with contributions from the community, you will see many new names in the ChangeLog Highlights which I list below, in no partciular order:

• Barry Kaplan
• Jeff Brown
• Philip Smith
• Kdx
• Geoffrey Wiseman
• Edson Tirelli

So a big thank you to all of the above, and of course to the rest of our community who regularly test drools and submit bug reports.

Of course there is also need for celebration as this is the first release candidate for drools, that means the code is now in feature freeze. We hope to do one more release candidate in 2-3 weeks and then a final 2-3 weeks after that. The documentation effort will continue throughout this time.

New and Noteworthy

The biggest highlight in this release is Jeff Brown's "Conway's Game of Life Example". The example uses JGoodies to create a graphical representation of this old favourite, it illustrates the use of drools-java for standard java business rules and also the use of Domain Specific Language.

<java:import>, <python:import> and <groovy:import> have been deprecated for <import>, but like <xxx:class> was deprecated many releases ago we will continue to support the notation for the 2.0 release.

We now have a complete ANT build script, so you can compile all of Drools and run the examples without Maven. It should be noted that the build environments use the same directory structures; this means you can build with Ant and run examples with Maven and vice-versa.

ChangeLog Highlights:

• Bug
  • DROOLS-259 - Add support for robust classLoader handling (Mark Proctor)
  • DROOLS-260 - <java:functions> doesn't see <java:import>-ed classes (kdx)
  • DROOLS-291 - Condition does not compile (Bob Mcwhirter)
  • DROOLS-292 - No warning when bean does not implement addPropertyChangeListener (Barry Kaplan)
  • DROOLS-299 - org.xml.sax.SAXParseException: <parameter> has an invalid parent (Mark Proctor)
  • DROOLS-305 - Invalid Handles after calling retractObject in WorkingMemory (Mark Proctor)
  • DROOLS-306 - drools-all produces error (Mark Proctor)
  • DROOLS-307 - Remove drools-annotation from drools-all (Mark Proctor)
  • DROOLS-313 - Import statements might cause the Rete network to be build erroneously (Edson Tirelli)
  • DROOLS-323 - Serialized Rule Bases seems to lose functions (Mark Proctor)
  • DROOLS-324 - iterator IllegalStateException on firing a temporal rule (Philip Smith)
  • DROOLS-329 - Correction to Handler logic in RuleSetReader (Mark Proctor)
  • DROOLS-336 - Detect ambiguously defined classes (kdx)
  • DROOLS-342 - Fix serialization for python and groovy (Mark Proctor)

• Improvement
  • DROOLS-325 - Improved Application Data Error Message (Geoffrey Wiseman)
  • DROOLS-328 - Upgrade to janino-2.3.2 (Mark Proctor)
  • DROOLS-333 - Update to groovy 1.0-jsr-01 (Mark Proctor)
  • DROOLS-334 - Make Clover work from maven (Mark Proctor)
  • DROOLS-337 - Update to antrl 2.7.5 (Mark Proctor)
  • DROOLS-340 - Turn off warning for jaxp1.2 compliancy (Mark Proctor)
  • DROOLS-341 - Centralise Import code and provide some level of caching (Mark Proctor)
  • DROOLS-343 - Added unit test for the Semaphore implementation (Mark Proctor)
  • DROOLS-344 - Add Conway's "Game of Life" example (Jeff Brown)
  • DROOLS-345 - Deprecate <smf:import> in favour of <import> (Mark Proctor)
  • DROOLS-100 - Ant Build File (Mark Proctor)
  • DROOLS-261 - <java:functions> should also let inner classes work (kdx)

• Task
  • DROOLS-227 - Document Ant Build Environment (Mark Proctor)

Release Overview

This is hopefully the last beta for Drools before we release a RC, assuming no ugly bugs rear their heads. We are very excited with new member Barry Kaplan's addition of POJO rules to Drools via JDK1.5 annotations. A domain specific language example has finally been written showing of the extensability of the SMF. We now allow pre JAXP1.2 parsers, which turns schema validation off, so warnings are not produced. Lastly modify has been profiled and optimised; it now follows the other systems out there in doing a retract and assert for a modify.

New and Noteworthy

@DroolsRule
public class FloorTooColdPumpOff
{
    @DroolsCondition
    public boolean isTooCold(@DroolsParameter("thermometer") Thermometer thermometer,
                             @DroolsParameter("control") TempuratureControl control) {
        return control.isTooCold(thermometer.getReading());
    }
    
    @DroolsCondition
    public boolean isPumpOff(@DroolsParameter("pump") HeatPump pump,
                             @DroolsParameter("thermometer") Thermometer thermometer) {
        return pump.getState() == OFF 
                && thermometer.getFloor().getHeatPump() == pump;
     }
    
    @DroolsConsequence
    public void consequence(@DroolsParameter("pump") HeatPump pump) {
        pump.setState(HEATING);
        System.out.println("FloorTooColdPumpOff: " + pump);
    }
}

<rule name="test1">
  <house:condition>
    <house:room name="lounge">
      <house:temperature>
        <house:greater-than scale="C">20</house:greater-than>
      </house:temperature>
    </house:room>
  </house:condition>

  <house:actions>
    <house:room name="lounge">
      <house:heating>off</house:heating>
    </house:room>
  </house:actions>
</rule>

Changelog

• Bug
  • DROOLS-262 - Retract followed by assert works much faster than modifyObject (Mark Proctor)
  • DROOLS-271 - Tighten annotation module exception handling/throwing (Barry Kaplan)

• New Feature
  • DROOLS-277 - Define rules using Java5 Annotations (Barry Kaplan)
  • DROOLS-284 - Domain Specific Example (Mark Proctor)

• Improvement
  • DROOLS-231 - provide a way to assert object containers (such as lists, maps, sets) by name in order to avoid unnecessary subclassing (Mark Proctor)
  • DROOLS-257 - Remove WorkingMemory param from Consequence.tuple(...) (Mark Proctor)
  • DROOLS-274 - Create interface for KnoweldgeHelper (Brian McCallister)
  • DROOLS-280 - Semaphore Constructors with Value (Mark Proctor)
  • DROOLS-282 - ConditionFactory should return Condition[] (Mark Proctor)
  • DROOLS-283 - Make RuleSetReader Handlers use type rather than localName (Mark Proctor)
  • DROOLS-286 - Allow pre JAXP1.2 parsers (Mark Proctor)
  • DROOLS-288 - Update to janino 2.1.0 (Mark Proctor)
  • DROOLS-289 - updated to groovy beta-9 (Mark Proctor)

• Task
  • DROOLS-228 - Eclipse Developer Instructions (Mark Procotr/Ciprian Bacalu)
  • DROOLS-229 - Idea Developer Instructions (Brian McCallister)
  • DROOLS-270 - Incorporate annotation module into multi-build (Barry Kaplan)

Release Overview

This is a very quick release to address DROOLS-236. With this release we fix the last known drools bug along with various exception handling improvements, making it an ideal candidate for those already using Drools in production.

Go to Project Downloads to get the latest Drools goodness.

Changelog

• Bug
  • DROOLS-79 - Exceptions Are Swallowed or Recast (Andy Barnett)
  • DROOLS-235 - difference between Drools manners and the original (Andy Barnett)
  • DROOLS-236 - NullPointerException and ArrayIndexOutOfBoundsException in PrimitiveLongMap (Mark Proctor)

• Improvement
  • DROOLS-218 - Replace throw/catch of Exception with specific exception classes (Andy Barnett)
  • DROOLS-278 - Better Exception handling for Scheduler (Mark Proctor)

New and Noteworthy

<java:functions>
    public void helloWorld(String hello)
    {
        System.err.println(hello + " World");
    }

    public void goodbyeWorld(String goodbye)
    {
        System.out.println(goodbye + " Cruel World");
    }
</java:functions>

StringSemaphore state = new StringSemaphore("state", "go");
workingMemory.assert(state);
-----------------------------------------------
<rule name="rule 1">
    <parameter identifier="state">
        <semaphore type="String" />
    </parameter>
                
    <java:condition>state.getValue( ).equals("go")</java:condition>
        
    <java:consequence>
        System.err.println( state );
    </java:consequence>
</rule>

Changelog

• Bug
  • DROOLS-223 - maxKey in PrimitiveLongMap is incorrect for the remove method (Mark Proctor)
  • DROOLS-237 - Unreported compilation problem (Andy Barnett)
  • DROOLS-240 - build breaks due to janino (Andy Barnett)
  • DROOLS-242 - TupleSet.removeTuple() can fail because of Collections.singletonMap (Andy Barnett)
  • DROOLS-243 - Generated GraphViz DOT Rete dumps should escape double-quotes (Andy Barnett)
  • DROOLS-246 - PythonFunctions class not JDK 1.3 compatible (Andy Barnett)
  • DROOLS-247 - Fibonacci and State Python Examples Failing with ArrayIndexOutOfBoundsException (Mark Proctor)
  • DROOLS-258 - Agenda.removeFromAgenda() upsets PriorityQueue integrity (Mark Proctor)

• New Feature
  • DROOLS-162 - Sharing of Condition and Join Nodes (Simon Harris)
  • DROOLS-164 - Function definitions for Rulesets (Mark Proctor)
  • DROOLS-253 - Named Semaphores (Mark Proctor)

• Improvement
  • DROOLS-92 - Unit testing for EventModel (Mark Proctor)
  • DROOLS-171 - Enhancements to Rete GraphViz-DOT Dumper (Andy Barnett)
  • DROOLS-215 - add getRule() to Activation related events (Mark Proctor)
  • DROOLS-217 - Fix .equals() methods to remove use of instanceof (Simon Harris)
  • DROOLS-219 - Rename like named classes in different packages / semantic modules (Simon Harris)
  • DROOLS-221 - Replace static rule builder methods with instance level methods (Simon Harris)
  • DROOLS-222 - Use checkstyle for smell detection (Andy Barnett)
  • DROOLS-233 - fix drools-all.jar for maven deployment goals (Bob McWhirter)
  • DROOLS-234 - Update ActivationFilter Rule name implementations to take a boolean value for accept (Mark Proctor)
  • DROOLS-238 - Allow assertion of dynamic facts from a consequence (Simon Harris)
  • DROOLS-239 - application data does not honor imports (Mark Proctor)
  • DROOLS-241 - Working Memory Events should provide access to the modified/retracted Object (Andy Barnett)
  • DROOLS-244 - Update project.properies to generate better eclipse projects (Mark Proctor)
  • DROOLS-248 - Drools Exceptions should support JDK 1.4 style Nested Exception functionality (Andy Barnett)
  • DROOLS-249 - Add ANTLR-generated files to CVS (Andy Barnett)

• Wish
  • DROOLS-225 - ydoc uml for javadocs (Mark Proctor, Bob McWhirter)
  • DROOLS-245 - Implement Waltz Benchmark from OPS5 Benchmark Suite in Drools (Andy Barnett)

Release Overview

The Drools development team is proud to announce the release of Beta-18.

Simon Harris has added Rocket Fuel to drools. Dependencies on Maps has been reduced and where possible typed Arrays are used instead; this has reduced memory consumption, drastically lowered garbage collection issues and combined with his priority queue for conflict resolution given us phenomenal speed increases.

Mark Proctor has been beavering away around every aspect of Drools from building a centralised fact repository based on a fast Map implementation especially for Drool's needs to improvements in the SMF bringing imports, class-field ObjectTypes, duration, and stronger java support via Janino.

Andy Barnett continues to keep the Ant build environment inline with the Maven one, for all those ant eaters out there, and does sterling work on documentation, code reviews and general tidy ups and of course ensures that Drools continues to be JSR-94 compliant - JSR-94 compliancy tests have now been integrated into the Drool build environment. He also added support for JavaBeans OnPropertyChange listeners.

Bob McWhirter has aided development with his sagely advice and creation of much better drools distribution deployment goals in maven, help making this release the easiest to use ever. Not only do you have the normal drools module jars you now also have a single uber-jar combining all classes for all modules in one jar and also a compiled zip/tar.gz archive of drools with all the needed dependencies.

Go to Project Downloads to get the latest Drools goodness.

New and Noteworthy

<rule-set name="test rule-set"
          xmlns="http://drools.org/rules"
          xmlns:java="http://drools.org/semantics/java"
          xmlns:xs="http://www.w3.org/2001/XMLSchema-instance"
          xs:schemaLocation="http://drools.org/rules rules.xsd
                             http://drools.org/semantics/java java.xsd">

<rule name="test rule" no-loop="true">
    ...
</rule>

AgendaFilter filter = new AgendaFilter()
{
    boolean accept(Activation activation)
    {
        if (activation.getRule().getName().equals("test rule")
        {
          return false;
        }
       
        return true;
    }
}
workingMemory.fireAllRules( filter );

<rule name="test rule">
    ....
    <duration seconds="15" />
    ....
</rule>   

<rule-set .....>
    <java:import>java.util.*<java:import>
    <java:import>org.drools.examples.fibonacci.Fibonacci<java:import>
   
    <rule name="test rule">
        <parameter identifier="fibonacci">
            <class>Fibonacci</class>
        </parameter>
        ...
    </rule>
</rule-set>

<rule-set .....>
    <application-data identifier="map">java.util.HashMap</application-data>
   
    <rule name="test rule">
       ...
       <consequence>
           map.put("string", value);
       </consequence>
    </rule>
<rule-set>

<rule name="test rule">
    <parameter identifier="a">
        <class-field field="state" value="A">State</class-field>
    </parameter>
    ...
</rule>

drools.clearAgenda( )

<rule name="test rule">
    <parameter identifier="fibonacci">
        <class>Fibonacci</class>
    </parameter>
    ...
</rule>

ChangeLog Highlights:

DROOLS-138 Imports now supported in rule-set for python, java, groovy <java:import>java.util.HashMap</java:import> (Mark Proctor)

DROOLS-173 Imports now supported for ObjectTypes in the <class> and <class-field> elements (Mark Proctor)

DROOLS-193 Custom ObjectType that uses field as an attribute <class-field>, see the State example for details (Mark Proctor)

DROOLS-137 Conditions and Consequences are no longer sensitive to white spaces. ApplicationData, imports and Declarations are now added synthetically to Janino, rather than using text mangling (Mark Proctor)

DROOLS-143 WorkingMemory speed up with FactHandleFactory now being a singleton (Jason Anderson)

DROOLS-152 We now have full Schema validation, see http://drools.org/Schema+Validation (Mark Proctor)

DROOLS-187 Schema validation can be disabled with system property "drools.schema.validating" (Mark Proctor)

DROOLS-157 Identity based uniqueness for facts (Simon Harris)

DROOLS-158 Supports retrieval of Object by Class (Bob McWhirter)

DROOLS-113 Access to asserted objects via drools.getObjects() (Bob McWhirter)

DROOLS-180 RuleSetReader has been made made easier to add new elements by refactoring to make it handler based (Mark Proctor)

DROOLS-183 Removed aspects and hard-coded event model (Mark Proctor)

DROOLS-184 Added support for ActivationCancelledEvent (Mark Proctor)

DROOLS-185 A user can now clear the agenda with drools.clearAgenda() (Mark Proctor)

DROOLS-186 Rules now support no-loop attribute to stop recursion (Mark Proctor)

DROOLS-188 Duration is now supported again, to schedule consequences for delayed firing (Mark Proctor)

DROOLS-189 New Distribution goals, to package all dependencies and make uber-jars (Mark Proctor/Bob McWhirter)

DROOLS-128 Access to rule name, drools.getRuleName(), is now available in conditions and consequences (Bob McWhirter)

DROOLS-190 Speed gains from making maps immutable (Simon Harris)

DROOLS-192 Conflict Resolution now supports Priority Queues for big performance improvements (Simon Harris)

DROOLS-191 Support for schemaLocation lookup in classpath; schemas are now more flexible than using fixed schemaSources (Mark Proctor)

DROOLS-163 Filters can now be added to an Agenda to block activations via AgendaFilter (MarkProctor)

DROOLS-207 Support added for JavaBean property change events (Andy Barnett)

DROOLS-212 Removed all traces of extractors from codebase. (Simon Harris)

DROOLS-210 Joins are now deterministic, which should create repeatable deterministic behaviour for Rete networks (Simon Harris)

DROOLS-211 Application Data should now be predefined so that java can precompile (Mark Proctor)

DROOLS-175 drools-java compilation exceptions now report the rule name, the text of the condition or consequence, and the compilation error message (Bob McWhirter)

DROOLS-213 Tuples have been made light-weight, HashMaps have been removed and replaced with array lookups, also they now only contain references to the TupleKey and WorkingMemory. This improves performance and memory usage (Simon Harris)

DROOLS-214 PrimitiveLongMap created for a fast, lightweight, centralised fact repository customised for Drool's needs. Based on Indexed Pages and Direct Address Tables (Mark Proctor)