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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

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03-behavioral/template-method/README.md Normal file
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# 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/

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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