在Drools中获得似乎是known issue的NPE 我正在使用drools 5.5.0.final。需要一些解决方法。
==> 'node heart beat arrival timeout' has been activated by the tuple [null]
21:16:15,150 WARN DefaultTimerJobInstance:63 - Unable to execute timer job!
Exception executing consequence for rule "node heart beat arrival timeout" in my.secret.company.mmc.cep: java.lang.NullPointerException
at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1297)
at org.drools.common.DefaultAgenda.fireTimedActivation(DefaultAgenda.java:1344)
at org.drools.common.Scheduler$ActivationTimerJob.execute(Scheduler.java:83)
at org.drools.time.SelfRemovalJob.execute(SelfRemovalJob.java:15)
at org.drools.time.impl.DefaultTimerJobInstance.call(DefaultTimerJobInstance.java:51)
at org.drools.time.impl.DefaultTimerJobInstance.call(DefaultTimerJobInstance.java:14)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:178)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:292)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at org.drools.base.DefaultKnowledgeHelper.retract(DefaultKnowledgeHelper.java:357)
at my.secret.company.mmc.cep.Rule_node_heart_beat_arrival_timeout_a41bd73ea00c4975b04415e563fb3e62.defaultConsequence(Rule_node_heart_beat_arrival_timeout_a41bd73ea00c4975b04415e563fb3e62.java:9)
at my.secret.company.mmc.cep.Rule_node_heart_beat_arrival_timeout_a41bd73ea00c4975b04415e563fb3e62DefaultConsequenceInvokerGenerated.evaluate(Unknown Source)
at my.secret.company.mmc.cep.Rule_node_heart_beat_arrival_timeout_a41bd73ea00c4975b04415e563fb3e62DefaultConsequenceInvoker.evaluate(Unknown Source)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1287)
... 11 more
==> 'node heart beat received' has been activated by the tuple [null, null]
Exception executing consequence for rule "node heart beat received" in my.secret.company.mmc.cep: java.lang.NullPointerException
at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1297)
at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1221)
at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1456)
at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:710)
at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:674)
at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:230)
at my.secret.company.cep.DroolsAssert.fireAllRules(DroolsAssert.java:302)
at my.secret.company.cep.DroolsAssert.insertAndFire(DroolsAssert.java:309)
at my.secret.company.mmc.cep.SuperCepRulesTest$1.run(SuperCepRulesTest.java:272)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at org.drools.base.DefaultKnowledgeHelper.retract(DefaultKnowledgeHelper.java:357)
at my.secret.company.mmc.cep.Rule_node_heart_beat_received_7df7ea24b0c74c25b8b0b86f4a8b1b1d.defaultConsequence(Rule_node_heart_beat_received_7df7ea24b0c74c25b8b0b86f4a8b1b1d.java:7)
at my.secret.company.mmc.cep.Rule_node_heart_beat_received_7df7ea24b0c74c25b8b0b86f4a8b1b1dDefaultConsequenceInvokerGenerated.evaluate(Unknown Source)
at my.secret.company.mmc.cep.Rule_node_heart_beat_received_7df7ea24b0c74c25b8b0b86f4a8b1b1dDefaultConsequenceInvoker.evaluate(Unknown Source)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1287)
... 13 more
答案 0 :(得分：0)
这是用例：
1.由相同的元组/对象触发的乘法规则
2.一条规则撤回/使其被触发的对象无效。
3.另一条规则已经安排好，对变化一无所知
它在DefaultKnowledgeHelper.retract（DefaultKnowledgeHelper.java:357）中因NullPointerException而失败，因为handle.getEntryPoint（）== null（无效）
5.5.0.final的内联修复（应该对逻辑进行适当的API更改以便清除）。
DefaultFactHandle.java
- private int id;
+ private volatile int id;
DefaultAgenda.java（fireActivation方法）
- try {
- increaseDormantActivations();
- decreaseActiveActivations();
+ try {
+ increaseDormantActivations();
+ decreaseActiveActivations();
+
+ for (FactHandle factHandle : activation.getFactHandles())
+ if (!((InternalFactHandle) factHandle).isValid())
+ return;
以下是需要考虑的其他堆栈跟踪：
Thread [pool-1-thread-1] (Suspended (modification of field entryPoint in DefaultFactHandle))
owns: DefaultAgenda (id=27071)
EventFactHandle(DefaultFactHandle).invalidate() line: 232
ReteooFactHandleFactory(AbstractFactHandleFactory).destroyFactHandle(InternalFactHandle) line: 94
NamedEntryPoint.retract(FactHandle, boolean, boolean, Rule, Activation) line: 606
DefaultKnowledgeHelper.retract(FactHandle) line: 357
Rule_node_heart_beat_arrival_timeout_a8e57af87b4c49aabea42ea1015155d4.defaultConsequence(KnowledgeHelper, EventImpl, FactHandle, ProducerTemplate) line: 9
Rule_node_heart_beat_arrival_timeout_a8e57af87b4c49aabea42ea1015155d4DefaultConsequenceInvokerGenerated.evaluate(KnowledgeHelper, WorkingMemory) line: not available
Rule_node_heart_beat_arrival_timeout_a8e57af87b4c49aabea42ea1015155d4DefaultConsequenceInvoker.evaluate(KnowledgeHelper, WorkingMemory) line: not available
DefaultAgenda.fireActivation(Activation) line: 1287
DefaultAgenda.fireTimedActivation(Activation, boolean) line: 1344
Scheduler$ActivationTimerJob.execute(JobContext) line: 83
SelfRemovalJob.execute(JobContext) line: 15
DefaultTimerJobInstance.call() line: 51
DefaultTimerJobInstance.call() line: 14
ScheduledThreadPoolExecutor$ScheduledFutureTask<V>(FutureTask<V>).run() line: 262
ScheduledThreadPoolExecutor$ScheduledFutureTask<V>.access$201(ScheduledThreadPoolExecutor$ScheduledFutureTask) line: 178
ScheduledThreadPoolExecutor$ScheduledFutureTask<V>.run() line: 292
ScheduledThreadPoolExecutor(ThreadPoolExecutor).runWorker(ThreadPoolExecutor$Worker) line: 1145
ThreadPoolExecutor$Worker.run() line: 615
Thread.run() line: 745
==> 'node heart beat arrival timeout' has been activated by the tuple [null]
21:16:15,150 WARN DefaultTimerJobInstance:63 - Unable to execute timer job!
Exception executing consequence for rule "node heart beat arrival timeout" in my.secret.company.mmc.cep: java.lang.NullPointerException
at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1297)
at org.drools.common.DefaultAgenda.fireTimedActivation(DefaultAgenda.java:1344)
at org.drools.common.Scheduler$ActivationTimerJob.execute(Scheduler.java:83)
at org.drools.time.SelfRemovalJob.execute(SelfRemovalJob.java:15)
at org.drools.time.impl.DefaultTimerJobInstance.call(DefaultTimerJobInstance.java:51)
at org.drools.time.impl.DefaultTimerJobInstance.call(DefaultTimerJobInstance.java:14)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:178)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:292)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at org.drools.base.DefaultKnowledgeHelper.retract(DefaultKnowledgeHelper.java:357)
at my.secret.company.mmc.cep.Rule_node_heart_beat_arrival_timeout_a41bd73ea00c4975b04415e563fb3e62.defaultConsequence(Rule_node_heart_beat_arrival_timeout_a41bd73ea00c4975b04415e563fb3e62.java:9)
at my.secret.company.mmc.cep.Rule_node_heart_beat_arrival_timeout_a41bd73ea00c4975b04415e563fb3e62DefaultConsequenceInvokerGenerated.evaluate(Unknown Source)
at my.secret.company.mmc.cep.Rule_node_heart_beat_arrival_timeout_a41bd73ea00c4975b04415e563fb3e62DefaultConsequenceInvoker.evaluate(Unknown Source)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1287)
... 11 more
==> 'node heart beat received' has been activated by the tuple [null, null]
Exception executing consequence for rule "node heart beat received" in my.secret.company.mmc.cep: java.lang.NullPointerException
at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1297)
at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:1221)
at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1456)
at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:710)
at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:674)
at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:230)
at my.secret.company.cep.DroolsAssert.fireAllRules(DroolsAssert.java:302)
at my.secret.company.cep.DroolsAssert.insertAndFire(DroolsAssert.java:309)
at my.secret.company.mmc.cep.SuperCepRulesTest$1.run(SuperCepRulesTest.java:272)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at org.drools.base.DefaultKnowledgeHelper.retract(DefaultKnowledgeHelper.java:357)
at my.secret.company.mmc.cep.Rule_node_heart_beat_received_7df7ea24b0c74c25b8b0b86f4a8b1b1d.defaultConsequence(Rule_node_heart_beat_received_7df7ea24b0c74c25b8b0b86f4a8b1b1d.java:7)
at my.secret.company.mmc.cep.Rule_node_heart_beat_received_7df7ea24b0c74c25b8b0b86f4a8b1b1dDefaultConsequenceInvokerGenerated.evaluate(Unknown Source)
at my.secret.company.mmc.cep.Rule_node_heart_beat_received_7df7ea24b0c74c25b8b0b86f4a8b1b1dDefaultConsequenceInvoker.evaluate(Unknown Source)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1287)
... 13 more