I have opened a ticket for the Sequential Logic work I'm doing. https://github.com/apache/incubator-kie-drools/issues/6182
I had a slight pause, but I have now resumed this work. The sequential engine is a dedicated subsystem that integrates with Rete's alpha network but uses a state machine rather than Rete's beta network to drive the sequence matching. The current temporal operators (before, after, etc.) all require beta joins, which are not as efficient as a state machine and are not as flexible for complex sequences with loops. When a sequence is matched, it enters the beta network for additional relational joins or rule firing. Future versions will optimise the network to avoid entering the beta network and fire immediately. Under the hood is a dedicated state machine that moves through states when signals are received from the SignalProcessors; the state machine is optimised for integrations for the sources it interacts with. Those signals are provided by logic gates once they become satisfied. The logic gates matched data received from the event stream, which itself is from the alpha network. The "feel" of the system is similar to how regular expression matching works. Because it only wants to attempt to match data for the current active sequence or subsequence, it uses a flat list of current patterns to match against. Bitmasks are used to get efficient routing from the input of data, to the pattern matching to the appropriate logic gates and their parent sequence. The branch can be found here: https://github.com/mdproctor/drools/tree/sequentiallogic It's early days, however a lot of the unit tests are in place to show how it works, but it's currently still very low level. For those interested, a lot of the unit tests can be found here: https://github.com/mdproctor/drools/tree/sequentiallogic/drools-test-coverage/test-compiler-integration/src/test/java/org/drools/mvel/integrationtests/phreak/sequencing A sequence has 1...n steps. Currently, it supports LogicCircuits, Actions, Aggregators and Subsequences. https://github.com/mdproctor/drools/tree/sequentiallogic/drools-base/src/main/java/org/drools/base/reteoo/sequencing/steps This test shows how to construct the logic gates, which are used within a LogicCircuit: https://github.com/mdproctor/drools/blob/sequentiallogic/drools-base/src/main/java/org/drools/base/reteoo/sequencing/signalprocessors/Gates.java https://github.com/mdproctor/drools/blob/sequentiallogic/drools-test-coverage/test-compiler-integration/src/test/java/org/drools/mvel/integrationtests/phreak/sequencing/PhreakSequencerLogicGateTest.java A LogicGate is a type of SignalProcessor: https://github.com/mdproctor/drools/blob/sequentiallogic/drools-base/src/main/java/org/drools/base/reteoo/sequencing/signalprocessors/LogicGate.java Loops can occur on individual SignalProcesses or on Subsequences. Where it's on a LogicGate, it tests the number of times the individual LogicGate is matched. https://github.com/mdproctor/drools/blob/sequentiallogic/drools-test-coverage/test-compiler-integration/src/test/java/org/drools/mvel/integrationtests/phreak/sequencing/PhreakSequencerSignalProcessorCounterTest.java Here is the conditional loop for SubSequence: https://github.com/mdproctor/drools/blob/sequentiallogic/drools-test-coverage/test-compiler-integration/src/test/java/org/drools/mvel/integrationtests/phreak/sequencing/PhreakSequencerSequenceLoopTest.java Timers are supported as well on signal processors and subsequences. The timer can be used to add delays or do timeouts. https://github.com/mdproctor/drools/blob/sequentiallogic/drools-test-coverage/test-compiler-integration/src/test/java/org/drools/mvel/integrationtests/phreak/sequencing/PhreakSequencerSignalProcessorTimerTest.java https://github.com/mdproctor/drools/blob/sequentiallogic/drools-test-coverage/test-compiler-integration/src/test/java/org/drools/mvel/integrationtests/phreak/sequencing/PhreakSequencerSequenceTimerTest.java Lastly, you can do aggregations over subsequences: https://github.com/mdproctor/drools/blob/sequentiallogic/drools-test-coverage/test-compiler-integration/src/test/java/org/drools/mvel/integrationtests/phreak/sequencing/PhreakSequencerAggregatorTest.java The next steps are to improve the unit tests and start to try and expose this in the DRL language itself so end users can start to use it. Regards Mark Mark
