Hmm … so the use of batch execution instead of InsertObjectCommand improved
things. However I have noticed that although rules are activating as expected,
and facts are being inserted, my queries don’t seem to get any results. For
instance with the following code:
Based on a stateless session:
List<Command> cmds = new ArrayList<Command>();
cmds.add(CommandFactory.newInsert(new IbanValidationRequest(iban),
"request"));
cmds.add(CommandFactory.newQuery("annotations", "annotations"));
ExecutionResults results =
ksession.execute(CommandFactory.newBatchExecution(cmds));
QueryResults queryResults = ( QueryResults ) results.getValue(
"annotations" );
System.out.println("Found [" + queryResults.size() + "]");
Based on a stateful session:
statefulSession.insert(new IbanValidationRequest(iban));
statefulSession.fireAllRules();
QueryResults queryResults =
statefulSession.getQueryResults("annotations");
System.out.println("Found [" + queryResults.size() + "]");
What I’m finding is that if I invoke a query against a stateful session, I get
a result. However, with stateless sessions, I am examining the
ExecutionResults, and finding that they do contain a reference to an
“annotations” QueryResults. However that collection of query results is empty.
btw - I’m also noticing that the code example in the user guide for batch
executions with queries doesn’t use the current syntax for adding a query
command. I’m guessing this syntax changed without an associated update to the
user guide.
Steve
On 11 Dec 2013, at 11:49, Wolfgang Laun <wolfgang.l...@gmail.com> wrote:
> The mean thing is that the code
> org.drools.command.CommandFactory
> uses the generic interface
> org.drools.command.Command<T>
> for all commands without specifying the generic parameter with the many
> newXyz methods. If it were written well, it would tell you what to
> expect from the command execution, since interface
> org.drools.runtime.CommandExecutor
> has the generic
> <T> T execute(Command<T> command)
>
> So you dig around in the code and may detect that ksession.execute(
> cmd ) with cmd being made by newInsertElements(...) returns a
> Collection<FactHandle>. Mighty helpful.
>
> Fixing the Experts would help a little, avoiding utter stupefaction.
>
> Cheers
> -W
>
>
>
> On 11/12/2013, Stephen Masters <stephen.mast...@me.com> wrote:
>> Thanks for that, Wolfgang. I have been working on something else for a few
>> days, but just switched over to batch execution, and that is giving me some
>> appropriate results (my tests are passing).
>>
>> Which leads me to the question ...
>>
>> Given that Example 3.4.1 in the Drools 5.5.0.Final user guide does not
>> compile, is that because there is a bug in the implementation of command
>> execution? Or is it a bug in the example. i.e.
>> The results should just not be assigned to anything?
>> The results (an ArrayList containing the facts which were just inserted)
>> should be assigned to a List of Object?
>> The example should just be removed from the user guide, as it is no longer a
>> valid/recommended approach?
>>
>> Anybody with thoughts on that? Assuming that the answer is a documentation
>> fix, I’ll be happy to correct it appropriately and submit a pull request.
>>
>> Cheers,
>>
>> Steve
>>
>>
>>
>>
>> On 4 Dec 2013, at 12:24, Wolfgang Laun <wolfgang.l...@gmail.com> wrote:
>>
>>> I think you have to put your insert command into a list
>>> List<Command<?>> cmds = new ArrayList();
>>> and pass this via batch execution
>>> CommandFactory.newBatchExecution( cmds )
>>>
>>> -W
>>>
>>> On 04/12/2013, Stephen Masters <stephen.mast...@me.com> wrote:
>>>> Hi folks,
>>>>
>>>> Can anyone explain how stateless session execution results should work?
>>>> Working through the docs and tracing the code, it’s getting a bit
>>>> confusing.
>>>>
>>>> Firstly, according to the user manual, one should be able to insert a
>>>> list
>>>> of facts as a Command, and get an instance of ExecutionResults back,
>>>> which
>>>> can then be queried. Here’s the example code:
>>>> StatelessKnowledgeSession ksession =
>>>> kbase.newStatelessKnowledgeSession();
>>>>
>>>> Command cmd = CommandFactory.newInsertElements( Arrays.asList( Object[]
>>>> {
>>>>
>>>> new Cheese( "stilton" ),
>>>>
>>>> new Cheese( "brie" ),
>>>>
>>>> new Cheese( "cheddar" ),
>>>>
>>>> });
>>>>
>>>> ExecutionResults bresults = ksession.execute( cmd );
>>>>
>>>> That doesn’t compile, so I fixed it as follows:
>>>>
>>>> Command cmd = CommandFactory.newInsertElements( Arrays.asList(
>>>> new Cheese( "stilton" ),
>>>> new Cheese( "brie" ),
>>>> new Cheese( "cheddar" )
>>>> ));
>>>> ExecutionResults bresults = ksession.execute( cmd );
>>>>
>>>> This does now compile, but running it throws a ClassCastException:
>>>> java.lang.ClassCastException: java.util.ArrayList cannot be cast to
>>>> org.drools.runtime.ExecutionResults
>>>>
>>>> Taking a look through the Drools code, it would appear that Command has
>>>> a
>>>> generic type, which in the case of an InsertElementsCommand is:
>>>> GenericCommand<Collection<FactHandle>>
>>>>
>>>> In turn, the execute command in StatelessKnowledgeSessionImpl casts its
>>>> result to that generic type:
>>>> public <T> T execute(Command<T> command) {
>>>> Object o = ((GenericCommand) command).execute( context );
>>>> ...
>>>> return (T) o;
>>>>
>>>> So the ClassCastException is because the execute method returns an
>>>> ArrayList
>>>> of FactHandle instead of an ExecutionResults.
>>>>
>>>> I’m assuming that I must have got the wrong end of the stick somewhere,
>>>> so
>>>> what should I be doing to get an ExecutionResults from a stateless
>>>> session,
>>>> which I can then query?
>>>>
>>>> Cheers,
>>>>
>>>> Steve
>>>
>>> _______________________________________________
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>>> rules-users@lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>>
>
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