Simple Properties

Introduction

Aplications might behave differently in different environments. One might have a specific configuration for Production Environment, which is different from Development Environment.

With simple properties, you can configure a different profile of properties for each of your environments, and access them through an easy to use DSL.

This library was inspired and is very similar to Spring Profiles, but only for Properties, and in a simpler way.

Adding to your project

Edit your build.gradle to contain the following dependency, from Maven Central:

implementation("com.kerooker.simpleproperties:simple-properties:{currentVersion}")

Usage Example

object MySystemProperties {

    private val simpleProperties = SimpleProperties()
    
    val databaseUrl: String = simpleProperties["my.database.url"]

}

File	Value of "my.database.url"
application-local.properties	localhost:3306
application-qa.properties	qa.database.server.intranet:3306
application-prod.properties	prod.database.server.intranet:7725

Launching app:

With local profile:

java -jar myapp.jar -Dactive_profiles=local

MySystemProperties.databaseUrl == "localhost:3306"

With production profile: java -jar myapp.jar -Dactive_profiles=prod

MySystemProperties.databaseUrl == "prod.database.server.intranet:7725"

Default profile

SimpleProperties will always try to read an optional default file application.properties. Any profile may override properties from the default file.

Configuring profiles

SimpleProperties will try to find your profiles in some places:

1. System Environment Variables
2. Java Properties
3. Defined at instantiation
   1. SimpleProperties(profiles = listOf("qa"))

More than one profile

Multiple profiles may be used at once, in a comma separated value in case of System (-Dactive_profiles=foo,bar,baz).

If keys are overriden, the last profile in the list will take priority.

Where to place files

Files are expected to be in the classpath. In Spring, this is usually done by placing the file in the resources folder, and this is allowed in Simple Properties too:

MyProject
`-- src
    `-- main
        |-- kotlin
        |   |-- Foo.kt
        |   `-- Bar.kt
        `-- resources
            |-- application.properties
            |-- application-foo.properties
            `-- application-bar.properties

You can customize where your files will be placed when creating the SimpleProperties instance:

SimpleProperties(filesLocation = "foo/bar")

Which allows for example the structure

MyProject
`-- resources
    `-- foo
        `-- bar
            |-- application.properties
            `-- application-foo.properties