topic Behavior of Multi Instance Tasks/Subprocesses on emtpy collections in Alfresco Archive

Behavior of Multi Instance Tasks/Subprocesses on emtpy collections

jakobtonn — Tue, 02 Dec 2014 08:18:12 GMT

In the application we are currently developing, we have the scenario of a multi-instance subprocesses which has a collection that might be empty. Our expectation was that if the collection was empty, Activiti would just skip the sub-process altogether and continue the execution after the sub-process

Re: Behavior of Multi Instance Tasks/Subprocesses on emtpy collections

jbarrez — Fri, 05 Dec 2014 15:11:20 GMT

Are you using current master version?

Cause, the code looks like it incorporates the '0' case: https://github.com/Activiti/Activiti/blob/master/modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/behavior/MultiInstanceActivityBehavior.java#L95

Also, the exception you get seems changed : https://github.com/Activiti/Activiti/blob/master/modules/activiti-engine/src/main/java/org/activiti/engine/impl/bpmn/behavior/ParallelMultiInstanceBehavior.java#L41

Re: Behavior of Multi Instance Tasks/Subprocesses on emtpy collections

jakobtonn — Fri, 05 Dec 2014 15:23:23 GMT

From the code you posted, it seems like the code does now work the way I had expected, I will re-check my test case against the current master state, if it indeed does work, my question is answered.

Re: Behavior of Multi Instance Tasks/Subprocesses on emtpy collections

schaumtier — Mon, 08 Dec 2014 12:46:09 GMT

There seems to be a difference between multi-instance subprocesses and multi-instance tasks. When using multi-instance tasks there is no problem with the current master version (at last the problem was in 5.16). But using multi-instance subprocesses with an empty collection results in a NullPointerException in MultiInstanceActivityBehavior.java in line 223.

Edit: The problem exists only if you use parallel multi-instance subprocesses. If you use sequential ones then it works as expected.

Re: Behavior of Multi Instance Tasks/Subprocesses on emtpy collections

jbarrez — Mon, 08 Dec 2014 13:52:41 GMT

Hmmm i see. Could you create a simple example process that demonstrates this problem? Then I can jump in straight away at fixing the bug.

Re: Behavior of Multi Instance Tasks/Subprocesses on emtpy collections

saig0 — Fri, 23 Jan 2015 14:08:08 GMT

Hi,

here is the simple example process with a parallel multi instance subprocess.

[img]https://www.dropbox.com/s/wrel8dbq33v83xj/ProcessWithMultiInstance.jpg?dl=1[/img]
Process definition: https://www.dropbox.com/s/oy8l3v8x5jbg04z/ProcessWithMultiInstance.bpmn?dl=0

If you start the process instance with an empty collection, activiti throw a null-pointer execption.
<java>
java.lang.NullPointerException
at org.activiti.engine.impl.bpmn.behavior.MultiInstanceActivityBehavior.setLoopVariable(MultiInstanceActivityBehavior.java:223)
at org.activiti.engine.impl.bpmn.behavior.ParallelMultiInstanceBehavior.leave(ParallelMultiInstanceBehavior.java:116)
at org.activiti.engine.impl.bpmn.behavior.MultiInstanceActivityBehavior.execute(MultiInstanceActivityBehavior.java:96)
at org.activiti.engine.impl.pvm.runtime.AtomicOperationActivityExecute.execute(AtomicOperationActivityExecute.java:60)
at org.activiti.engine.impl.interceptor.CommandContext.performOperation(CommandContext.java:96)
at org.activiti.engine.impl.persistence.entity.ExecutionEntity.performOperationSync(ExecutionEntity.java:631)
at org.activiti.engine.impl.persistence.entity.ExecutionEntity.performOperation(ExecutionEntity.java:626)
at org.activiti.engine.impl.pvm.runtime.AtomicOperationTransitionNotifyListenerStart.eventNotificationsCompleted(AtomicOperationTransitionNotifyListenerStart.java:52)
</java>

Test case:
<java>
    @Deployment(resources = "ProcessWithMultiInstance.bpmn")
    @Test
    public void multiInstanceWithEmptyCollection()
    {
        Map<String, Object> vars = new HashMap<String, Object>();
        vars.put("messages", Collections.EMPTY_LIST);
        activitiRule.getRuntimeService().startProcessInstanceByKey("myProcess", vars);

        assertThat(activitiRule.getHistoryService().createHistoricProcessInstanceQuery().count(), is(1L));
    }
</java>
Complete test case: https://www.dropbox.com/s/n83f17b0441521w/MultiInstanceTest.java?dl=0

Greetings.

Re: Behavior of Multi Instance Tasks/Subprocesses on emtpy collections

jbarrez — Tue, 10 Feb 2015 17:02:28 GMT

You are correct. Fixed it : https://github.com/Activiti/Activiti/commit/053d8e7965de8e42758f196bbc098d46e0be0221

Thanks for the easy to use process definition and test. This really helped me speed up to resolve the problem!

Re: Behavior of Multi Instance Tasks/Subprocesses on emtpy collections

gi00vani_kun — Fri, 27 Feb 2015 14:01:56 GMT

The important fix is provided by ParallelMultiInstanceBehavior.java

After applying the fix in activiti-engine-5.16.4.jar I got the below error when executing my project

<code>
Caused by: org.apache.ibatis.exceptions.PersistenceException:
### Error updating database. Cause: java.sql.SQLIntegrityConstraintViolationException: ORA-02291: integrity constraint (BB.ACT_FK_EXE_PROCINST) violated - parent key not found

### The error may involve org.activiti.engine.impl.persistence.entity.ExecutionEntity.insertExecution-Inline
### The error occurred while setting parameters
### SQL: insert into ACT_RU_EXECUTION (ID_, REV_, PROC_INST_ID_, BUSINESS_KEY_, PROC_DEF_ID_, ACT_ID_, IS_ACTIVE_, IS_CONCURRENT_, IS_SCOPE_,IS_EVENT_SCOPE_, PARENT_ID_, SUPER_EXEC_, SUSPENSION_STATE_, CACHED_ENT_STATE_, TENANT_ID_, NAME_) values ( ?, 1, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ? )
### Cause: java.sql.SQLIntegrityConstraintViolationException: ORA-02291: integrity constraint (BB.ACT_FK_EXE_PROCINST) violated - parent key not found

at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:23)
at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:150)
at org.apache.ibatis.session.defaults.DefaultSqlSession.insert(DefaultSqlSession.java:137)
at org.activiti.engine.impl.db.DbSqlSession.flushInserts(DbSqlSession.java:758)
at org.activiti.engine.impl.db.DbSqlSession.flush(DbSqlSession.java:590)
at org.activiti.engine.impl.interceptor.CommandContext.flushSessions(CommandContext.java:211)
at org.activiti.engine.impl.interceptor.CommandContext.close(CommandContext.java:137)
at org.activiti.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:66)
at org.activiti.spring.SpringTransactionInterceptor$1.doInTransaction(SpringTransactionInterceptor.java:47)
at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:133)
at org.activiti.spring.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:45)
at org.activiti.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:31)
at org.activiti.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecutorImpl.java:40)
at org.activiti.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecutorImpl.java:35)
at org.activiti.engine.impl.RuntimeServiceImpl.startProcessInstanceById(RuntimeServiceImpl.java:101)
at org.activiti.explorer.ui.process.listener.StartProcessInstanceClickListener.buttonClick(StartProcessInstanceClickListener.java:71)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:510)
… 33 more
Caused by: java.sql.SQLIntegrityConstraintViolationException: ORA-02291: integrity constraint (BB.ACT_FK_EXE_PROCINST) violated - parent key not found

at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:445)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:396)
at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:879)
at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:450)
at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:192)
at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:531)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:207)
at oracle.jdbc.driver.T4CPreparedStatement.executeForRows(T4CPreparedStatement.java:1044)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1329)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3593)
at oracle.jdbc.driver.OraclePreparedStatement.execute(OraclePreparedStatement.java:3694)
at oracle.jdbc.driver.OraclePreparedStatementWrapper.execute(OraclePreparedStatementWrapper.java:1378)
at org.apache.ibatis.executor.statement.PreparedStatementHandler.update(PreparedStatementHandler.java:41)
at org.apache.ibatis.executor.statement.RoutingStatementHandler.update(RoutingStatementHandler.java:66)
at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:45)
at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:100)
at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:75)
at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:148)
… 52 more
</code>

Re: Behavior of Multi Instance Tasks/Subprocesses on emtpy collections

gi00vani_kun — Fri, 27 Feb 2015 15:48:58 GMT

I've fixed this with a simpler solution:

<code>
<subProcess id="subprocess1" name="Sub Process">
           <multiInstanceLoopCharacteristics isSequential="false" activiti:collection="list2process">
                   <!– completionCondition>${nrOfCompletedInstances/nrOfInstances > 0.5}</completionCondition –>
           </multiInstanceLoopCharacteristics>
</code>

And Java hack :

<code>
if (f.size() > 1) {
   f.remove(0);
   execution.setVariable("list2process", f);
}
</code>