01. How to contribute

To work on a new pattern you need to do the following steps:

1. If there is no issue for the new pattern yet, raise new issue. Comment on the issue that you are working on it so that others don't start work on the same thing.
2. Fork the repository.
3. Create a new folder for the pattern. The rough structure of the new folder would be as follows:
   • etc (every resource related to the pattern, like diagrams)
   • src (the source code of the pattern)
   • index.md (the description of the pattern)
   • pom.xml (the Maven project file)
4. Implement the code changes in your fork. Remember to add sufficient comments documenting the implementation. Reference the issue id e.g. #52 in your commit messages.
5. Format the code according to Google Java Style Guide
   • Eclipse configuration
   • IntelliJ configuration
   • The build fails if the code is not properly formatted (see coding conventions)
   • The build also fails if static analysis finds violations
6. Create a simple class diagram from your example code and put it inside the etc folder.
7. Add description of the pattern in index.md and link to the class diagram. (Attention, all internal links must be relative to the pattern subdirectory, otherwise the links don't link properly on the website)
8. Create a pull request.

Structure of the index.md file

--- # this is so called 'Yaml Front Matter', read up on it here: http://jekyllrb.com/docs/frontmatter/
layout: pattern # layout must allways be pattern
title: Best Pattern Ever # the properly formatted title
folder: best-pattern-ever # the folder name in which this pattern lies
permalink: /patterns/best-pattern-ever/ # the permalink to the pattern, to keep this uniform please stick to /patterns/FOLDER/

# both categories and tags are Yaml Lists
# you can either just pick one or write a list with '-'s
# usable categories and tags are listed here: https://github.com/iluwatar/java-design-patterns/blob/gh-pages/_config.yml
categories: creational # categories of the pattern
tags: # tags of the pattern
 - best
 - ever
 - awesome
---

**Intent:** Makes your code awesome

![alt text](./etc/best_pattern.png "Best Pattern Ever")

**Applicability:** Use the Best Pattern Ever pattern when

* you want to be the best
* you need to ...

**Real world examples:**

* [Nowhere](http://no.where.com)

To add a new category or tag you need to edit the _config.yml file of the gh-pages branch. In there you should find 2 yaml lists with the respective names category-list and tag-list.

To work on one of the non-pattern issues you need to do the following steps:

1. Check that the issue has help wanted badge
2. Comment on the issue that you are working on it
3. Fork the repository.
4. Implement the code changes in your fork. Remember to add sufficient comments documenting the implementation. Reference the issue id e.g. #52 in your commit messages.
5. Create a pull request.

For creating/editing UML diagrams you need ObjectAid UML Explorer for Eclipse.

For inspiration check out the following sources:

• there is a good list of design patterns at Wikipedia
• Martin Fowler's Catalog of Patterns of Enterprise Application Architecture
• pattern language for microservices
• Microsoft's Cloud Design Patterns

Links to patterns applied in real world applications are welcome. The links should be added to the corresponding section of the index.md.