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
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/