gistfile1.txt

    private static Method hackMethod;

    static {
        try {
            hackMethod = Class.forName("org.drools.planner.core.score.buildin.simple.SimpleScoreCalculator").getMethod("increment");
        } catch (ClassNotFoundException e) {
            throw new IllegalStateException("No such class", e);
        } catch (NoSuchMethodException e) {
            throw new IllegalStateException("No such method", e);
        }
    }

...


    public void retractLeftTuple(final LeftTuple leftTuple,
                                 final PropagationContext context,
                                 final InternalWorkingMemory workingMemory) {
        final Activation activation = (Activation) leftTuple.getObject();

        // activation can be null if the LeftTuple previous propagated into a no-loop
        if ( activation == null ) {
            return;
        }
        
        final DefaultAgenda agenda = (DefaultAgenda) workingMemory.getAgenda();
        
        AgendaItem item = ( AgendaItem ) activation;
        item.removeAllBlockersAndBlocked(agenda);
        
        if ( agenda.isDeclarativeAgenda() && activation.getFactHandle() == null ) {
            // This a control rule activation, nothing to do except update counters. As control rules are not in agenda-groups etc.
            agenda.decreaseDormantActivations(); // because we know ControlRules fire straight away and then become dormant
            return; 
        } else {
            // we are retracting an actual Activation, so also remove it and it's handle from the WM. 
            agenda.removeActivation( (AgendaItem) activation ); 
        }

        if (  activation.isActivated() ) {
            // on fact expiration, we don't remove the activation, but let it fire
            if ( context.getType() == PropagationContext.EXPIRATION && context.getFactHandleOrigin() != null ) {
            } else {
                activation.remove();

                if ( activation.getActivationGroupNode() != null ) {
                    activation.getActivationGroupNode().getActivationGroup().removeActivation( activation );
                }

                if ( activation.getActivationNode() != null ) {
                    final InternalRuleFlowGroup ruleFlowGroup = (InternalRuleFlowGroup) activation.getActivationNode().getParentContainer();
                    ruleFlowGroup.removeActivation( activation );
                }
                leftTuple.decreaseActivationCountForEvents();

                ((EventSupport) workingMemory).getAgendaEventSupport().fireActivationCancelled( activation,
                                                                                                workingMemory,
                                                                                                ActivationCancelledCause.WME_MODIFY );
                agenda.decreaseActiveActivations();
            }
        } else {
            agenda.decreaseDormantActivations();
        }


// ge0ffrey stuff start <===================================
        Object scoreCalculator = workingMemory.getGlobal("scoreCalculator");
        try {
            hackMethod.invoke(scoreCalculator);
        } catch (IllegalAccessException e) {
            throw new IllegalStateException("Problem invoking method", e);
        } catch (InvocationTargetException e) {
            throw new IllegalStateException("Problem invoking method", e);
        }
// ge0ffrey stuff stop <===================================


        workingMemory.getTruthMaintenanceSystem().removeLogicalDependencies( activation,
                                                                             context,
                                                                             this.rule );        
    }