MapSourceAndSinks.mapWithUpdating generates java.lang.ClassCastException: class java.lang.Integer cannot be cast to class java.lang.String (java.lang.Integer and java.lang.String are in module java.base of loader 'bootstrap') at com.hazelcast.jet.impl.execution.TaskletExecutionService$BlockingWorker.run(TaskletExecutionService.java:250)

[sebvige]

Running the mapWithUpdating "as is " generates the exception described above.

Changing String.valueOf(e.getValue()) to e.getValue()
and
? oldValue +"--even"
: oldValue +"--odd"
to
? oldValue
: oldValue

makes the code running ok but with no parsing and suffixing

[viliam-durina]

Please share the entire code of the pipeline. Is the type parameter of the source (at drawFrom) correct, does it correspond to the actual type of data in the source?

[sebvige]

Here is the code as it is today in the repo :

 private static Pipeline mapWithUpdating(String sourceMapName, String sinkMapName) {
        Pipeline pipeline = Pipeline.create();

        pipeline.drawFrom(Sources.<Integer, Integer>map(sourceMapName))
                .map(e -> entry(e.getKey(), String.valueOf(e.getValue())))
                .drainTo(
                        Sinks.mapWithUpdating(
                                sinkMapName,
                                (oldValue, item) ->
                                        item.getKey() % 2 == 0
                                                ? oldValue + "-even"
                                                : oldValue + "-odd"
                        )
                );

        return pipeline;
    }

[viliam-durina]

I suspect that the sink map already contains items with Integer type. The sink map has to be of type <Integer, String> and all items in it have to match the signature. If you share the stack trace of the exception I could confirm.

[sebvige]

Here is the stack trace :
------------Map with Updating ----------------

25:31,512 [192.168.1.17]:5704 [jet] [3.1.1-SNAPSHOT] class java.lang.Integer cannot be cast to class java.lang.String (java.lang.Integer and java.lang.String are in module java.base of loader 'bootstrap')
java.lang.ClassCastException: class java.lang.Integer cannot be cast to class java.lang.String (java.lang.Integer and java.lang.String are in module java.base of loader 'bootstrap')
	at com.hazelcast.jet.function.BiFunctionEx.apply(BiFunctionEx.java:43)
	at com.hazelcast.jet.impl.connector.HazelcastWriters$ApplyFnEntryProcessor.handle(HazelcastWriters.java:647)
	at com.hazelcast.jet.impl.connector.HazelcastWriters$ApplyFnEntryProcessor.process(HazelcastWriters.java:639)
	at com.hazelcast.map.impl.operation.EntryOperator.process(EntryOperator.java:318)
	at com.hazelcast.map.impl.operation.EntryOperator.operateOnKeyValueInternal(EntryOperator.java:181)
	at com.hazelcast.map.impl.operation.EntryOperator.operateOnKey(EntryOperator.java:166)
	at com.hazelcast.map.impl.operation.MultipleEntryOperation.run(MultipleEntryOperation.java:76)
	at com.hazelcast.spi.Operation.call(Operation.java:170)
	at com.hazelcast.spi.impl.operationservice.impl.OperationRunnerImpl.call(OperationRunnerImpl.java:210)
	at com.hazelcast.spi.impl.operationservice.impl.OperationRunnerImpl.run(OperationRunnerImpl.java:199)
	at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.process(OperationThread.java:147)
	at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.process(OperationThread.java:177)
	at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.process(OperationThread.java:131)
	at com.hazelcast.spi.impl.operationexecutor.impl.OperationThread.run(OperationThread.java:110)

[viliam-durina]

That's it. Your sink map contained entries with Integer value.

        map.put(1, 1);

        Pipeline p = Pipeline.create();
        p.drawFrom(SourceBuilder.batch("src", procCtx -> null)
                .<Entry<Integer, String>>fillBufferFn((ctx, buf) -> {
                    buf.add(entry(1, "foo"));
                    buf.close();
                })
                .build())
         .drainTo(Sinks.mapWithUpdating("sinkMap", (oldValue, item) ->
                 item.getKey() % 2 == 0
                         ? oldValue + "-even"
                         : oldValue + "-odd"));

        inst.newJob(p).join();

failed with:

java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String
	at com.hazelcast.jet.function.BiFunctionEx.apply(BiFunctionEx.java:41)
	at com.hazelcast.jet.impl.connector.HazelcastWriters$ApplyFnEntryProcessor.handle(HazelcastWriters.java:647)