Study guide

Every feature works on this PC with Java and SQL Server only - no cloud AI service, no API key. Read the classes in the order shown; the comments at the top of each class explain the idea.

How a request flows

core/TenantFilter finds the company (sub-domain or the user you act as) and puts it in TenantContext.
core/TenantIdentifierResolver gives that id to Hibernate: every entity with @TenantId is filtered automatically.
core/GlobalModelAdvice adds the company's branding (#509) and the menu to every page.
The feature's controller calls its service; services use JPA repositories or JdbcTemplate (always with tenant_id = ?).
Templates ask feature flags (#507) with ${@featureFlags.on('key')}.

Run, reset, test

Run: mvnw spring-boot:run -Dspring-boot.run.profiles=local

Reset the demo data: run database/reset-database.sql, then restart.

Tests: mvnw test (OCR accuracy, face recognition, NL parser, statistics, sentiment ...).

Sub-domain tenant: open http://siamsport.localhost:PORT/ - the browser sends *.localhost to this PC.

#	Feature	Technique	Read these classes
496	AI Chatbot	Intent rules + TF-IDF cosine similarity over knowledge-base articles	`chatbot/ChatbotServicechatbot/TfIdfIndexcore/Text`
497	AI Auto-fill	Regular expressions + heuristics + date parsing, scored per field	`autofill/AutoFillServiceautofill/LeadController`
498	OCR	Otsu threshold, line projection, connected components, template matching against rendered fonts	`ocr/OcrEngineocr/GlyphLibraryocr/SampleImageService`
499	Face Recognition	Local Binary Pattern Histograms (LBPH) + chi-square distance + threshold	`face/LbphRecognizerface/FaceServiceface/SyntheticFaces`
500	Recommendation Engine	Item-based collaborative filtering (cosine) + content similarity + popularity fallback	`recommend/RecommendationService`
501	Predictive Analytics	Holt-Winters seasonal smoothing, linear regression, logistic regression (gradient descent)	`predict/ForecastServicepredict/ChurnModel`
502	Natural Language Search	Rule-based parser: vocabulary from the database, number/compare phrases, sort words	`nlsearch/QueryParsernlsearch/NlSearchService`
503	Document Intelligence	Keyword classifier + field extractors + arithmetic validation; PDFBox for PDF text	`docintel/DocumentAnalyzerdocintel/SampleDocuments`
504	Sentiment Analysis	Lexicon with negation and intensifiers + Naive Bayes trained on labelled reviews	`sentiment/SentimentAnalyzersentiment/NaiveBayessentiment/Lexicon`
505	Anomaly Detection	Robust z-score (median / MAD), hour-of-day rarity, velocity window, rolling 3-sigma band	`anomaly/AnomalyDetectoranomaly/AnomalyService`
506	A/B Testing	Hash bucketing (FNV-1a), two-proportion z-test, confidence intervals, sample size	`abtest/AbTestServiceabtest/Stats`
507	Feature Flags	Rule evaluation with reasons, sticky percentage buckets, audit log	`flags/FeatureFlagServiceflags/FlagController`
508	Multi-tenant	Hibernate @TenantId + CurrentTenantIdentifierResolver + sub-domain / session resolution	`core/TenantFiltercore/TenantIdentifierResolvertenancy/TenantService`
509	White-label	Per-tenant CSS custom properties, validated colours, contrast check	`branding/BrandingServicebranding/BrandingController`
510	Geofencing	Haversine distance for circles, ray casting for polygons, state change events	`geofence/GeoMathgeofence/GeofenceService`