[rules-users] NullPointerException when using Drools rule template

[Roger Smith]

All -

I tried out Drools rule template with a with a proptotype app. Drools is
throwing NullPointerException as below. I would much appreciate if someone
on this list can help.

java.lang.NullPointerException
    at
org.drools.template.parser.DefaultTemplateColumn.createCellCondition(DefaultTemplateColumn.java:68)
    at
org.drools.template.parser.DefaultTemplateColumn.addCondition(DefaultTemplateColumn.java:91)
    at
org.drools.template.parser.DefaultTemplateRuleBase.createColumnConditions(DefaultTemplateRuleBase.java:105)
    at
org.drools.template.parser.DefaultTemplateRuleBase.createTemplateRule(DefaultTemplateRuleBase.java:98)
    at
org.drools.template.parser.DefaultTemplateRuleBase.getDTRules(DefaultTemplateRuleBase.java:85)
    at
org.drools.template.parser.DefaultTemplateRuleBase.<init>(DefaultTemplateRuleBase.java:64)
    at
org.drools.template.parser.TemplateDataListener.<init>(TemplateDataListener.java:76)
    at
org.drools.template.parser.TemplateDataListener.<init>(TemplateDataListener.java:52)
    at
org.drools.template.ObjectDataCompiler.compile(ObjectDataCompiler.java:44)


Here is my code

        KnowledgeBuilder kBuilder =
KnowledgeBuilderFactory.newKnowledgeBuilder();
        ObjectDataCompiler converter = new ObjectDataCompiler();
        InputStream dis = new FileInputStream( new File(
"/home/pranab/Projects/gridx/ct11_1.drl" ) );
        if (null == dis){
          System.out.println("null rule template stream");
          return;
        }

        Collection<Map<String,Object>> paramMaps = new
ArrayList<Map<String,Object>>();

        Map<String,Object> params = new HashMap<String,Object>();

        params.put("summerOnPeakPrimaryRate", new Integer(299));
        params.put("summerOnPeakSecondaryRate", new Integer(524));
        params.put("summerSemiPeakPrimaryRate", new Integer(176));
        params.put("summerSemiPeakSecondaryRate", new Integer(305));
        params.put("summerOffPeakPrimaryRate", new Integer(139));
        params.put("summerOffPeakSecondaryRate", new Integer(243));
        params.put("winterOnPeakPrimaryRate", new Integer(249));
        params.put("winterOnPeakSecondaryRate", new Integer(438));
        params.put("winterSemiPeakPrimaryRate", new Integer(176));
        params.put("winterSemiPeakSecondaryRate", new Integer(305));
        params.put("winterOffPeakPrimaryRate", new Integer(139));
        params.put("winterOffPeakSecondaryRate", new Integer(243));
        paramMaps.add(params);

        String drl = converter.compile(paramMaps, dis);
        Reader rdr = new StringReader( drl );
        kBuilder.add( ResourceFactory.newReaderResource(rdr),
ResourceType.DRL);


The line in blue is throwing the exception. This code is very similar to the
example code in Drools Expert guide.

Best,

Roger
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