[jbpm-issues] [JBoss JIRA] Resolved: (JBPM-1169) NPE in org.jbpm.graph.node.Decision.execute() when using transitions with null conditions migrated from JBPM 3.0

NPE in org.jbpm.graph.node.Decision.execute() when using transitions with null conditions migrated from JBPM 3.0 ---------------------------------------------------------------------------------------------------------------- Key: JBPM-1169 URL: https://jira.jboss.org/jira/browse/JBPM-1169 Project: JBoss jBPM Issue Type: Bug Components: Core Engine Affects Versions: jBPM 3.2.2 Environment: win2000, JBPM 3.2.2, Jboss 4.2.2, Eclipse Europa 3.3 Reporter: Julien Kronegg Assignee: Thomas Diesler Original Estimate: 6 weeks Remaining Estimate: 6 weeks A NullPointerException is raised by org.jbpm.graph.node.Decision.execute(ExecutionContext) if the table JBPM_DECISIONCONDITIONS row has null EXPRESSION_ field. The following conditions must meet: 1) initially, the user has a JBPM database in version 3.0 and a decision with conditional transitions 2) one of the conditional condition is cleared, which leads to setting the field EXPRESSION_ to null in the database 3) the JBPM database migrated from 3.0 schema to version 3.2 Note: the JBPM 3.2 database is (almost?) the same as the version 3.1, so the bug should also occur in version 3.1 (not tested). The exception is: Exception in thread "main" org.jbpm.graph.def.DelegationException at org.jbpm.graph.def.GraphElement.raiseException(GraphElement.java:387) at org.jbpm.graph.def.GraphElement.raiseException(GraphElement.java:378) at org.jbpm.graph.node.Decision.execute(Decision.java:148) at org.jbpm.graph.def.Node.enter(Node.java:319) at org.jbpm.graph.def.Transition.take(Transition.java:151) at org.jbpm.graph.def.Node.leave(Node.java:394) at org.jbpm.graph.node.StartState.leave(StartState.java:70) at org.jbpm.graph.exe.Token.signal(Token.java:195) at org.jbpm.graph.exe.Token.signal(Token.java:140) at org.jbpm.graph.exe.ProcessInstance.signal(ProcessInstance.java:271) at com.sample.TestDecisionNPE.main(TestDecisionNPE.java:53) Caused by: java.lang.NullPointerException at org.jbpm.jpdl.el.impl.JbpmExpressionEvaluator.translateExpressionToDollars(JbpmExpressionEvaluator.java:52) at org.jbpm.jpdl.el.impl.JbpmExpressionEvaluator.evaluate(JbpmExpressionEvaluator.java:38) at org.jbpm.jpdl.el.impl.JbpmExpressionEvaluator.evaluate(JbpmExpressionEvaluator.java:30) at org.jbpm.graph.node.Decision.execute(Decision.java:110) ... 8 more This bug can be tested using the following test case: package com.sample; import java.lang.reflect.Field; import java.util.ArrayList; import java.util.List; import org.jbpm.graph.def.ProcessDefinition; import org.jbpm.graph.def.Transition; import org.jbpm.graph.exe.ProcessInstance; import org.jbpm.graph.node.Decision; import org.jbpm.graph.node.DecisionCondition; public class TestDecisionNPE { public static final void main(String[] args) throws SecurityException, NoSuchFieldException, IllegalArgumentException, IllegalAccessException{ ProcessDefinition processDefinition = ProcessDefinition.parseXmlString( "<process-definition>" + " <start-state>" + " <transition to='d' />" + " </start-state>" + " <decision name='d'>" + " <transition name='one' to='a'>" + " <condition>#{a == 1}</condition>" + " </transition>" + " <transition name='two' to='b'>" + " <condition>#{a == 2}</condition>" + " </transition>" + " <transition name='three' to='c'>" + " <condition>#{a == 3}</condition>" + " </transition>" + " </decision>" + " <state name='a' />" + " <state name='b' />" + " <state name='c' />" + "</process-definition>"); // start-state. ProcessInstance processInstance = new ProcessInstance(processDefinition); // Update a transition decision condition as if it was on the old format // by setting the condition to null (i.e. no condition). // Build a decisionConditions list (emulates an old database from // JBPM 3.0, obsolete JBPM_DECISIONCONDITION table). List decision_conditions = new ArrayList(); decision_conditions.add(new DecisionCondition("one", null)); Decision decision = (Decision) processDefinition.getNode("d"); Field field = decision.getClass().getDeclaredField("decisionConditions"); field.setAccessible(true); field.set(decision, decision_conditions); // fire the transition (as we have an old decision condition set, org.jbpm.graph.node.Decision#execute will raise a NullPointerException). processInstance.signal(); } } The bug can be corrected using the following code in the execute() method (added lines ends with "JK") : // backwards compatible mode based on separate DecisionCondition's Iterator iter = decisionConditions.iterator(); while (iter.hasNext() && (transition==null)) { DecisionCondition decisionCondition = (DecisionCondition) iter.next(); if (decisionCondition.expression!=null) {//JK Object result = JbpmExpressionEvaluator.evaluate(decisionCondition.getExpression(), executionContext); if (Boolean.TRUE.equals(result)) { if (transition!=null) { transition.removeConditionEnforcement(); } String transitionName = decisionCondition.getTransitionName(); transition = getLeavingTransition(transitionName); } } else {//JK String transitionName = decisionCondition.getTransitionName();//JK transition = getLeavingTransition(transitionName);//JK }//JK Note that the JBPM 3.0.4 version had this check against null values.