Coordination Patterns — State · Singleton  +  Enterprise Integration Backbone

GoF · State Pattern
«interface»  PositionState
FlatState
BUY → Long
SELL → Short
LONG
SHORT
LongState
SELL → Flat
HOLD → Long
FLAT
LONG
ShortState
BUY → Flat
SELL → Short
FLAT
SHORT
Benefit
Eliminates fragile if/else chains — each state owns its own transitions entirely
GoF · Singleton Pattern
ReportingService — Single Thread-Safe Instance
Private INSTANCE exposed by getInstance(); prints reports and records decisions for all 3 engines with thread-safe bookkeeping.
Enterprise Integration Patterns
9 patterns · route groups
Concern Patterns Used Route
Ingest & Normalize Polling Consumer · Message Translator · Message Filter tick-ingestion
Fan Out Statistics Splitter turns each valid tick into average, moving average, stddev, min, and max computations statistics-engine
Build Decisions Selective Consumer · Correlation Identifier · Aggregator rebuild complete SignalSnapshots per engine engine routes
Expose Failures Invalid Message Channel · Dead Letter Channel keep bad records visible global