Class Main

Method Details

• main

  public static void main(String[] args) throws Exception

  This method performs the main task of constructing an framework instance and starting its execution. The following functions are performed when invoked:

  1. Examine and verify command-line arguments. The launcher accepts a "-b" command line switch to set the bundle auto-deploy directory and a single argument to set the bundle cache directory.
  2. Read the system properties file. This is a file containing properties to be pushed into System.setProperty() before starting the framework. This mechanism is mainly shorthand for people starting the framework from the command line to avoid having to specify a bunch of -D system property definitions. The only properties defined in this file that will impact the framework's behavior are the those concerning setting HTTP proxies, such as http.proxyHost, http.proxyPort, and http.proxyAuth. Generally speaking, the framework does not use system properties at all.
  3. Read the framework's configuration property file. This is a file containing properties used to configure the framework instance and to pass configuration information into bundles installed into the framework instance. The configuration property file is called config.properties by default and is located in the conf/ directory of the Felix installation directory, which is the parent directory of the directory containing the felix.jar file. It is possible to use a different location for the property file by specifying the desired URL using the felix.config.properties system property; this should be set using the -D syntax when executing the JVM. If the config.properties file cannot be found, then default values are used for all configuration properties. Refer to the Felix constructor documentation for more information on framework configuration properties.
  4. Copy configuration properties specified as system properties into the set of configuration properties. Even though the Felix framework does not consult system properties for configuration information, sometimes it is convenient to specify them on the command line when launching Felix. To make this possible, the Felix launcher copies any configuration properties specified as system properties into the set of configuration properties passed into Felix.
  5. Add shutdown hook. To make sure the framework shutdowns cleanly, the launcher installs a shutdown hook; this can be disabled with the felix.shutdown.hook configuration property.
  6. Create and initialize a framework instance. The OSGi standard FrameworkFactory is retrieved from META-INF/services and used to create a framework instance with the configuration properties.
  7. Auto-deploy bundles. All bundles in the auto-deploy directory are deployed into the framework instance.
  8. Start the framework. The framework is started and the launcher thread waits for the framework to shutdown.

  It should be noted that simply starting an instance of the framework is not enough to create an interactive session with it. It is necessary to install and start bundles that provide a some means to interact with the framework; this is generally done by bundles in the auto-deploy directory or specifying an "auto-start" property in the configuration property file. If no bundles providing a means to interact with the framework are installed or if the configuration property file cannot be found, the framework will appear to be hung or deadlocked. This is not the case, it is executing correctly, there is just no way to interact with it.

  The launcher provides two ways to deploy bundles into a framework at startup, which have associated configuration properties:

  • Bundle auto-deploy - Automatically deploys all bundles from a specified directory, controlled by the following configuration properties:
    • felix.auto.deploy.dir - Specifies the auto-deploy directory from which bundles are automatically deploy at framework startup. The default is the bundle/ directory of the current directory.
    • felix.auto.deploy.action - Specifies the auto-deploy actions to be found on bundle JAR files found in the auto-deploy directory. The possible actions are install, update, start, and uninstall. If no actions are specified, then the auto-deploy directory is not processed. There is no default value for this property.
  • Bundle auto-properties - Configuration properties which specify URLs to bundles to install/start:
    • felix.auto.install.N - Space-delimited list of bundle URLs to automatically install when the framework is started, where N is the start level into which the bundle will be installed (e.g., felix.auto.install.2).
    • felix.auto.start.N - Space-delimited list of bundle URLs to automatically install and start when the framework is started, where N is the start level into which the bundle will be installed (e.g., felix.auto.start.2).

  These properties should be specified in the config.properties so that they can be processed by the launcher during the framework startup process.

  Parameters:

  args - Accepts arguments to set the auto-deploy directory and/or the bundle cache directory.

  Throws:

  Exception - If an error occurs.

• loadSystemProperties

  public static void loadSystemProperties()

  Loads the properties in the system property file associated with the framework installation into System.setProperty(). These properties are not directly used by the framework in anyway. By default, the system property file is located in the conf/ directory of the Felix installation directory and is called "system.properties". The installation directory of Felix is assumed to be the parent directory of the felix.jar file as found on the system class path property. The precise file from which to load system properties can be set by initializing the "felix.system.properties" system property to an arbitrary URL.

• loadConfigProperties

  public static Map<String,String> loadConfigProperties()

  Loads the configuration properties in the configuration property file associated with the framework installation; these properties are accessible to the framework and to bundles and are intended for configuration purposes. By default, the configuration property file is located in the conf/ directory of the Felix installation directory and is called "config.properties". The installation directory of Felix is assumed to be the parent directory of the felix.jar file as found on the system class path property. The precise file from which to load configuration properties can be set by initializing the "felix.config.properties" system property to an arbitrary URL.

  Returns:

  A Properties instance or null if there was an error.

• copySystemProperties

  public static void copySystemProperties(Map configProps)