Enum Environment

src/main/java/org/bukkit/World.java:745–784

Represents various map environment types that a world may be

     * Represents various map environment types that a world may be
     */
    public enum Environment {
        /**
         * Represents the "normal"/"surface world" map
         */
        NORMAL(0),
        /**
         * Represents a nether based map ("hell")
         */
        NETHER(-1),
        /**
         * Represents a sky-lands based map ("heaven")
         */
        SKYLANDS(1);

        private final int id;
        private static final Map<Integer, Environment> lookup = new HashMap<Integer, Environment>();

        private Environment(int id) {
            this.id = id;
        }

        /**
         * Gets the dimension ID of this environment
         *
         * @return dimension ID
         */
        public int getId() {
            return id;
        }

        public static Environment getEnvironment(int id) {
            return lookup.get(id);
        }

        static {
            for (Environment env : values()) {
                lookup.put(env.getId(), env);
            }
        }
    }
}