Template Method: sync post code blocks to repo exactly (DataMigration/CsvMigration/ApiMigration were entirely different from repo), Java 25, H6 file labels, fix stale console output, README mapping

03-behavioral/template-method/README.md

@@ -0,0 +1,29 @@
+# Template Method Design Pattern — Java Example
+
+**Pattern:** Behavioral → Template Method
+**Article:** https://ankurm.com/template-method-design-pattern-java/
+
+## What this example shows
+
+A data migration pipeline with a fixed skeleton and variable steps. `DataMigration` declares `migrate()` as `final` — the sequence (connect, validate, read, transform, write, notify, disconnect) can never be reordered or skipped by a subclass. `getSourceName()`, `connect()`, `readData()`, and `transformData()` are abstract steps each subclass must supply; `validate()`, `writeData()`, and `disconnect()` are concrete steps shared by everyone; `sendNotification()` is a hook with a default of `true` that a subclass can override. `CsvMigration` uses every default unchanged. `ApiMigration` overrides the hook to stay silent. `Main` runs both through the identical skeleton.
+
+## How to run
+
+```bash
+javac template-method/*.java -d out/template-method
+java -cp out/template-method template.Main
+```
+
+Requires Java 25.
+
+## Post Section ↔ File Mapping
+
+| Post Section | File(s) |
+|---|---|
+| Implementation: Data Migration Pipeline — the abstract class & template method | `DataMigration.java` |
+| Implementation: Data Migration Pipeline — CsvMigration | `CsvMigration.java` |
+| Implementation: Data Migration Pipeline — ApiMigration | `ApiMigration.java` |
+| Implementation: Data Migration Pipeline — wiring it together | `Main.java` |
+
+Article: https://ankurm.com/template-method-design-pattern-java/
+All patterns: https://ankurm.com/design-patterns-java/

README.md

@@ -445,6 +445,21 @@ javac 03-behavioral/strategy/*.java -d out/strategy
 java -cp out/strategy strategy.Main
 ```
 
+### Template Method (`03-behavioral/template-method/`)
+
+| Post Section | File(s) |
+|---|---|
+| Implementation: Data Migration Pipeline — the abstract class & template method | `DataMigration.java` |
+| Implementation: Data Migration Pipeline — CsvMigration | `CsvMigration.java` |
+| Implementation: Data Migration Pipeline — ApiMigration | `ApiMigration.java` |
+| Implementation: Data Migration Pipeline — wiring it together | `Main.java` |
+
+Run it:
+```bash
+javac 03-behavioral/template-method/*.java -d out/template-method
+java -cp out/template-method template.Main
+```
+
 ## Reference
 
 - *Design Patterns: Elements of Reusable Object-Oriented Software* — Gamma, Helm, Johnson, Vlissides