[rules-users] NullPointerException when using Drools rule template

[Wolfgang Laun]

Seeing the template .drl would help to resolve this. Are all @{parameter}s
declared in the template header?
-W

2010/11/9 Roger Smith <rogersmith1711 at gmail.com>

>
> 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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