java-environment's Introduction

Environment

ARM Canada inc.

Environment file parser and matcher

Usage

Used to parse file formatted as below to get environment variable

DB_CONNECTION=mysql
DB_HOST=localhost

Basic

Load environment

You can load any List<String> into the environment. You can either read a file into an ArrayList and load it to the environment

public class Main
{
    public static void main(String[] args)
    {
        List<String> values = new ArrayList<>();
        values.add("DB_CONNECTION=mysql");
        values.add("DB_HOST=localhost");
        Environment.load(values);
    }    
}

Getting a variable

Once you have loaded the variable, you can get them using the get() facade method. You can also pass in a second argument as a fallback value

public class Main
{
    public static void main(String[] args)
    {
        Environment.get("DB_CONNECTION"); // would return mysql
        Environment.get("DB_DATABASE", "undefined"); // would return undefined since we did not provided any "DB_DATABASE" key
    }    
}

Setting a variable

You can override any value at anytime with set() method

public class Main
{
    public static void main(String[] args)
    {
        Environment.set("DB_CONNECTION", "sqlserver");
    }    
}

Class property annotation

The package comes with a @EnvironmentVariable annotation that allows an automatic assignation with the environment variables. All you have to do is call the attach() facade method on any annotated class.

Note: Annotated properties must be public

public class Database
{
    @EnvironmentVariable(key = "DB_CONNECTION")
    public String connection;
}
public class Main
{
    public static void main(String[] args)
    {
        Database db = new Database();
        Environment.attach(db);
        db.connection; // is now equals to "mysql"        
    }    
}

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