uk.ac.starlink.task

Class TerminalEnvironment

java.lang.Object

uk.ac.starlink.task.TerminalEnvironment

All Implemented Interfaces:

Environment

public class TerminalEnvironment
extends Object
implements Environment

Implementation of Environment which accepts an initial command line, and communicates with the user using standard input and standard output.

This environment is somewhat deprecated in favour of the more capable LineEnvironment.

Author:

Mark Taylor (Starlink)

Field Summary

Fields

Modifier and Type	Field and Description
static int	NUM_TRIES The number of goes you get to put in an invalid parameter.

Constructor Summary

Constructors

Constructor and Description
TerminalEnvironment(String[] args, Parameter<?>[] params) Constructs a new Environment based on a String array containing supplied arguments, and a list of parameters which may be encountered.

Method Summary

Modifier and Type	Method and Description
void	acquireValue(Parameter<?> par) Sets the value of a parameter.
void	clear(Parameter<?> par)
void	clearValue(Parameter<?> par) Clears a value for a given parameter.
PrintStream	getErrorStream() Returns System.err.
String[]	getNames() Returns an array of parameter names which have been specified.
PrintStream	getOutputStream() Returns System.out.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

NUM_TRIES

public static int NUM_TRIES

The number of goes you get to put in an invalid parameter.

Constructor Detail

TerminalEnvironment

public TerminalEnvironment(String[] args,
                           Parameter<?>[] params)
                    throws UsageException

Constructs a new Environment based on a String array containing supplied arguments, and a list of parameters which may be encountered. The initial arguments may have the form value or name=value; in the former case they must correspond to a parameter with a non-zero position attribute indicating where it is expected on the command line, and in the latter case the name must correspond to the name of one of the parameters in params.

Parameters:

args - an array of words found on the command line

params - an array of Parameter objects which this Environment may be asked to get values for

Throws:

UsageException

Method Detail

clear

public void clear(Parameter<?> par)

acquireValue

public void acquireValue(Parameter<?> par)
                  throws TaskException

Sets the value of a parameter. If it a value has been specified on the command line then that is used, otherwise any known default is used, otherwise the user is prompted on standard output and response got from standard input.

A more configurable order (cf ADAM PPATH/VPATH) could be implemented by adding some methods to Parameter and getting this method to query them.

Specified by:

acquireValue in interface Environment

Parameters:

par - the parameter whose value is to be set

Throws:

TaskException

clearValue

public void clearValue(Parameter<?> par)

Description copied from interface: Environment

Clears a value for a given parameter.

Specified by:

clearValue in interface Environment

Parameters:

par - the Parameter whose value is to be cleared

getNames

public String[] getNames()

Description copied from interface: Environment

Returns an array of parameter names which have been specified. The result is not necessarily an exhaustive list of all parameters whose values can be retrieved from this environment, since an interactive environment may be able to prompt the user for values, but it can give a list of values provided explicitly or without interactive prompts.

Specified by:

getNames in interface Environment

Returns:

array of names of known supplied parameters

getOutputStream

public PrintStream getOutputStream()

Returns System.out.

Specified by:

getOutputStream in interface Environment

Returns:

System.out

getErrorStream

public PrintStream getErrorStream()

Returns System.err.

Specified by:

getErrorStream in interface Environment

Returns:

System.err