# Composite Design Pattern — Java Example

**Pattern:** Structural → Composite
**Article:** https://ankurm.com/composite-design-pattern-java/

## What this example shows

Builds a file system tree where files (leaves) and directories (composites) share the same `FileSystemItem` interface. Callers compute size or print the tree without ever checking whether a node is a file or a directory.

## How to run

```bash
javac composite/*.java -d out/composite
java -cp out/composite composite.Main
```

Requires Java 25.

## Post Section ↔ File Mapping

| Post Section | File(s) |
|---|---|
| The Problem: Treating Leaves and Containers Uniformly | illustrative only — not part of this repository's runnable example |
| Step 1 — The Component Interface | `FileSystemItem.java` |
| Step 2 — The Leaf (File) | `File.java` |
| Step 3 — The Composite (Directory) | `Directory.java` |
| Building and Using the Tree | `Main.java` |

Article: https://ankurm.com/composite-design-pattern-java/
All patterns: https://ankurm.com/design-patterns-java/