Package org.javalite.app_config

Class AppConfig

  • All Implemented Interfaces:
    Map<String,​String>
    public class AppConfig
extends Object
implements Map<String,​String>
    This class allows configuration of applications for different deployment environments, such as development, test, staging, production, etc. Configuration is done either with property files on the classpath, or on a file system.

    1. Classpath configuration

    Applications could have environment-specific files, whose names follow this pattern: name.properties, where name is a name of a deployment environment, such as "development", "staging", "production", etc. You can also provide a global file, properties from which will be loaded in all environments: global.properties.

    In all cases the files need to be on the classpath in package /app_config.

    Environment-specific file will have an "environment" part of the file name match to an environment variable called ACTIVE_ENV or system property active_env. The system property will override the environment variable!

    Such configuration is easy to achieve in Unix shell:

    export ACTIVE_ENV=test

    If environment variable ACTIVE_ENV is missing, it defaults to "development".

    You can also provide an environment as a system property active_env. System property overrides environment variable ACTIVE_ENV

    Example:

    If there are four files packed into a /app_config package:
    • global.properties
    • development.properties
    • staging.properties
    • production.properties
    And the ACTIVE_ENV=staging, then properties will be loaded from the following files:
    • global.properties
    • staging.properties

    2. File configuration

    In addition to properties on classpath, you can also specify a single file for properties to loaded from a file system. Use a system property with a full path to a file like: 
         java -cp $CLASSPATH com.myproject.Main -Dapp_config.properties=/opt/directory1/myproject.properties
    The file-based configuration overrides classpath one. If you have a property defined in both, the classpath configuration will be completely ignored and the file property will be used.

    Property substitution

    AppConfig allows a property substitution to make it possible to refactor large property files by specifying a repeating value once. If your property file has these properties: 
     first.name=John
   phrase= And the name is ${first.name}
    than this code will print And the name is John: 
     System.out.println(p("phrase"));
    Note: The order of properties does not matter.
    Author:
    Igor Polevoy

    • Constructor Detail

      • AppConfig

        public AppConfig()

    • Method Detail

      • setActiveEnv

        public static void setActiveEnv​(String activeEnv)
        You can change the environment dynamically. Attention!!! This method should only be used for tests! Careful out there...
        Parameters:
        activeEnv - new environment value

      • init

        public static void init()

      • reload

        public static void reload()
        Used in tests.

      • setProperty

        public static String setProperty​(String name,
                                 String value)
        Sets a property in memory. If property exists, it will be overwritten, if not, a new one will be created.
        Parameters:
        name - - name of property
        value - - value of property
        Returns:
        old value

      • getAsProperty

        public static Property getAsProperty​(String key)
        Returns property instance corresponding to key.
        Parameters:
        key - key for property.
        Returns:
        Property for this key.

      • getProperty

        public static String getProperty​(String key)
        Returns property value for a key.
        Parameters:
        key - key of property.
        Returns:
        value for this key, null if not found.

      • getAllProperties

        public static Map<String,​String> getAllProperties()

      • activeEnv

        public static String activeEnv()
        Returns current environment name as defined by environment variable ACTIVE_ENV.
        Returns:
        current environment name as defined by environment variable ACTIVE_ENV.

      • isInTestMode

        public static boolean isInTestMode()
        Checks if running in a context of a test by checking of a presence of a class org.junit.Test on classpath.
        Returns:
        true if class org.junit.Test is on classpath, otherwise returns false

      • isInTestEnv

        public static boolean isInTestEnv()
        Returns:
        true if environment name as defined by environment variable ACTIVE_ENV is "testenv".

      • isInProduction

        public static boolean isInProduction()
        Returns:
        true if environment name as defined by environment variable ACTIVE_ENV is "production".

      • isInDevelopment

        public static boolean isInDevelopment()
        Returns:
        true if environment name as defined by environment variable ACTIVE_ENV is "development".

      • isInStaging

        public static boolean isInStaging()
        Returns:
        true if environment name as defined by environment variable ACTIVE_ENV is "staging".

      • getKeys

        public static List<String> getKeys​(String prefix)
        Returns all keys that start with a prefix
        Parameters:
        prefix - prefix for properties.

      • getProperties

        public static List<String> getProperties​(String prefix)
        Return all numbered properties with a prefix. For instance if there is a file: 
             prop.1=one
     prop.2=two
        .. and this method is called: 
             List props = AppConfig.getProperties("prop");
        then the resulting list will have all properties starting from prop. This method presumes consecutive numbers in the suffix.
        Parameters:
        prefix - prefix of numbered properties.
        Returns:
        list of property values.

      • pInteger

        public static Integer pInteger​(String propertyName)
        Read property as Integer.
        Parameters:
        propertyName - name of property.
        Returns:
        property as Integer.

      • pDouble

        public static Double pDouble​(String propertyName)
        Read property as Double.
        Parameters:
        propertyName - name of property.
        Returns:
        property as Double.

      • pFloat

        public static Float pFloat​(String propertyName)
        Read property as Float.
        Parameters:
        propertyName - name of property.
        Returns:
        property as Float.

      • pBoolean

        public static Boolean pBoolean​(String propertyName)
        Read property as Boolean.
        Parameters:
        propertyName - name of property.
        Returns:
        property as Boolean.