All Packages  Class Hierarchy  This Package  Previous  Next  Index

Class semper.util.system.Env

java.lang.Object
   |
   +----semper.util.system.Env

public class Env

extends Object

Version:

$Revision: 1.6 $ $Date: 1997/09/26 11:03:44 $

Author:

N. Asokan ([email protected])

Env()

getEnvVarsTable()

Dump the list of known environment variables and their values

getLocalEnvVar(String)

Get the local value of an environment variable; for variables that were set via this front end, this must be the same as the actual value in the environment

getSystemEnvVar(String)

Get the value of a variable from the system environment; for variables that were set via this front end, this must be the same as the local value maintained in the front-end.

init()

Initialise the environment interaction front-end.

initEnv()

Initialise the environment by setting all known variables to the values according to the local table

isInitialised()

Check if the environment interaction front-end has been initialised

removeEnvVar(String, String)

Remove an environment variable.

setEnvVar(String, String, String)

Set the specified environment variable.

 public Env()

 public static void init() throws EnvException

Initialise the environment interaction front-end.

Throws: EnvException

if initialisation failed

 public static boolean isInitialised()

Check if the environment interaction front-end has been initialised

Returns:

true/false

 public static void setEnvVar(String name,
                              String value,
                              String creator) throws EnvException

Set the specified environment variable. Once set, only the creator of the environment variable can reset or remove that variable. Currently, no access control checks are done though.

Parameters:

name - name of the variable

value - the proposed new value

creator - identity of the creator (for now, it can be any string; eventually it must be a name that can be authenticated by external means)

Throws: EnvException

if the variable cannot be set

 public static void removeEnvVar(String name,
                                 String creator) throws EnvException

Remove an environment variable. Only the creator of a variable can remove it. The variable is removed from the local table but NOT from the environment itself. To unset an environment variable from the environment, the process must be restarted.

Parameters:

name - name of the variable

creator - identity of the creator

Throws: EnvException

if removal didn't succeed

 public static String getLocalEnvVar(String name)

Get the local value of an environment variable; for variables that were set via this front end, this must be the same as the actual value in the environment

Parameters:

name - name of the variable

Returns:

(local) value of the variable

See Also:

getSystemEnvVar

 public static String getSystemEnvVar(String name)

Get the value of a variable from the system environment; for variables that were set via this front end, this must be the same as the local value maintained in the front-end. Be very careful when using this function: on some platforms (windows, linux,...), if the environment variable was not already set, java seg faults. If the variable is already set, there is no problem.

Parameters:

name - name of the variable

Returns:

value of the variable in the environment

See Also:

getLocalEnvVar

 public static Enumeration getEnvVarsTable()

Dump the list of known environment variables and their values

Returns:

Enumeration containing the environment variables

See Also:

EnvVar

 public static void initEnv() throws EnvException

Initialise the environment by setting all known variables to the values according to the local table

Throws: EnvException

when initialisation has failed

All Packages  Class Hierarchy  This Package  Previous  Next  Index