Re: [rules-users] NullPointerException when using Drools rule template

There is probably something wrong with your drl. Try starting from an empty drl file and then add each of the rules and definitions in it one by one until you find the one causing problems. Then you can produce a test case and create a JIRA issue for it if it doesn't already exist - as it should at least be giving a useful error message and not throwing a null pointer exception. Thomas From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Roger Smith Sent: 09 November 2010 06:41 To: rules-users(a)lists.jboss.org Subject: [rules-users] NullPointerException when using Drools rule template 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 ________________________________ ************************************************************************************** This message is confidential and intended only for the addressee. If you have received this message in error, please immediately notify the postmaster(a)nds.com and delete it from your system as well as any copies. The content of e-mails as well as traffic data may be monitored by NDS for employment and security purposes. To protect the environment please do not print this e-mail unless necessary. NDS Limited. Registered Office: One London Road, Staines, Middlesex, TW18 4EX, United Kingdom. A company registered in England and Wales. Registered no. 3080780. VAT no. GB 603 8808 40-00 **************************************************************************************