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Class calypso.util.Shell

java.lang.Object
   |
   +----calypso.util.Shell

public class Shell

extends Object

implements Runnable

The shell is easily extended with inner classes:

 ...
 Shell sh = new Shell();
 sh.registerCommand("echo",
   new ShellCommand("echoes all given parameters")
   {
     public void execute(StringTokenizer parameters_, Shell sh_)
     {
       while (parameters_.hasMoreTokens())
       {
         sh_.getOut().print(parameters_.nextToken() + " ");
       }
       sh_.getOut().print("\n");
     }
   });
 sh.run();
 

Version:

$Reveision: $

Author:

Juhana Räsänen

See Also:

ShellCommand

DEF_CMDNAME

The default command name.

DEF_PROMPT

The default prompt.

Shell()

Constructs a new shell that uses System.out and System.in as streams and default prompt.

Shell(boolean)

Constructs a new shell that uses System.out and System.in as streams and default prompt with current time.

Shell(InputStream, PrintStream)

Constructs a shell with given streams and the default prompt.

Shell(InputStream, PrintStream, String)

Constructs a new shell with given streams and prompt.

Shell(String)

Constructs a new shell with given prompt.

Shell(String, boolean)

Constructs a new shell with given prompt and current time.

clone()

Makes a shallow copy of the Shell.

getIn()

Returns the input stream

getOut()

Returns the output stream

main(String[])

A main method for testing and executing simple scripts.

registerCommand(String, ShellCommand)

Registers a new command to the shell.

run()

The main loop of the shell.

setExitFlag(boolean)

Sets the exit status flag.

setPrompt(String)

Sets the prompt shown to the user.

unregisterCommand(String)

Unregisters a command so that the shell does not recognize it anymore.

 public static final String DEF_CMDNAME

The default command name. The default command is run when the user gives a command that is not stored in the command table.

 public static final String DEF_PROMPT

The default prompt.

 public Shell()

Constructs a new shell that uses System.out and System.in as streams and default prompt.

 public Shell(boolean showTime_)

Constructs a new shell that uses System.out and System.in as streams and default prompt with current time.

Parameters:

showTime_ - true if current time is to be shown

 public Shell(String prompt_)

Constructs a new shell with given prompt. System.in and System.out are used as the streams.

Parameters:

prompt_ - the user prompt

 public Shell(String prompt_,
              boolean showTime_)

Constructs a new shell with given prompt and current time. System.in and System.out are used as the streams.

Parameters:

prompt_ - the user prompt

showTime_ - true if current time is to be shown

 public Shell(InputStream is_,
              PrintStream os_)

Constructs a shell with given streams and the default prompt.

Parameters:

is_ - the input stream

os_ - the output stream

 public Shell(InputStream is_,
              PrintStream os_,
              String prompt_)

Constructs a new shell with given streams and prompt. This constructor is called eventually by the other constructors and it also creates the default shell commands (as anonymous inner classes).

Parameters:

is_ - the input stream

os_ - the output stream

prompt_ - the user prompt

 public Object clone()

Makes a shallow copy of the Shell. The command table is copied using Hashtable.clone().

Returns:

The new copy of the Shell

Overrides:

clone in class Object

 public void registerCommand(String cmdname_,
                             ShellCommand cmd_)

Registers a new command to the shell. If there is an existing command with the given name, the previous command is discarded.

Parameters:

cmdname_ - the name of the command (must be a signle word)

cmd_ - the actual command implementation

 public void unregisterCommand(String cmdname_)

Unregisters a command so that the shell does not recognize it anymore.

Parameters:

cmdname_ - the name of the command

 public void setExitFlag(boolean value_)

Sets the exit status flag. If set as true, the shell command loop will exit the next round

Parameters:

value_ - true or false

 public void setPrompt(String prompt_)

Sets the prompt shown to the user.

Parameters:

prompt_ - the new prompt string

 public PrintStream getOut()

Returns the output stream

Returns:

the output stream

 public InputStream getIn()

Returns the input stream

Returns:

the input stream

 public void run()

The main loop of the shell. Executes until the exitFlag becomes true. Prints user the command prompt, reads a new command line from the input stream, parses it and executes the command if found.

 public static void main(String argv[])

A main method for testing and executing simple scripts.

Parameters:

command - line parameters (not used)

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