Class LineEnvironment

  • All Implemented Interfaces:
    Environment

    public class LineEnvironment
    extends java.lang.Object
    implements Environment
    Execution environment for use from the command line. Arguments are supplied as LineWord objects.
    Since:
    27 Nov 2006
    Author:
    Mark Taylor
    • Constructor Summary

      Constructors 
      Constructor Description
      LineEnvironment()
      Constructs a LineEnvironment without any additional initialisation.
      LineEnvironment​(java.lang.String[] args, Parameter[] params)
      Constructs a new LineEnvironment, initialising it with a set of command line arguments.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void acquireValue​(Parameter param)
      Obtains a legal value for a given parameter from the environment and sets the parameter's value accordingly.
      void checkParameters​(Parameter[] params)
      Checks that this environment's values are compatible with the given list of parameters.
      void clearValue​(Parameter par)
      Clears a value for a given parameter.
      java.lang.String[] getAssignments()
      Returns an array of strings, one for each parameter assignment which was actually used (via acquireValue(uk.ac.starlink.task.Parameter)) for this environment.
      java.io.PrintStream getErrorStream()
      Returns an output stream into which error or logging output from a task can be written.
      boolean getInteractive()
      Determines whether we are running interactively.
      java.lang.String[] getNames()
      Returns an array of parameter names which have been specified.
      java.io.PrintStream getOutputStream()
      Returns an output stream into which text output from a task can be written.
      java.lang.String getParamHelp​(Parameter param)
      Returns the help string for a given parameter.
      boolean getPromptAll()
      Determines whether all parameters which haven't received explicit values on the command line should be prompted for.
      java.lang.String[] getUnused()
      Returns a string containing any words of the input argument list which were never queried by the application to find their value.
      boolean isHidden​(Parameter param)
      Determines whether a parameter is "hidden", that is its value should not be revealed to prying eyes.
      boolean paramNameMatches​(java.lang.String envName, Parameter param)
      Indicates whether a parameter name supplied from the environment is a reference to a given parameter.
      void setErrorStream​(java.io.PrintStream err)
      Sets the destination stream for standard error.
      void setInteractive​(boolean interactive)
      Sets whether we are running interactively or not.
      void setOutputStream​(java.io.PrintStream out)
      Sets the destination stream for standard out.
      void setPromptAll​(boolean prompt)
      Sets whether all parameters which haven't received explicit values on the command line should be prompted for.
      void setWords​(LineWord[] words)
      Sets the words supplying the parameter values for this environment.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • LineEnvironment

        public LineEnvironment()
        Constructs a LineEnvironment without any additional initialisation. A subsequent call of setWords(uk.ac.starlink.task.LineWord[]) must be made before it is interrogated for values.
      • LineEnvironment

        public LineEnvironment​(java.lang.String[] args,
                               Parameter[] params)
                        throws UsageException
        Constructs a new LineEnvironment, initialising it with a set of command line arguments. These are checked against a set of parameters. The arguments must be of the form name=value, or just value for positional arguments. If any of these refer to parameters not in the params list, an exception will be thrown.
        Parameters:
        args - command-line arguments
        params - parameters that args provide values for
        Throws:
        UsageException
    • Method Detail

      • setWords

        public void setWords​(LineWord[] words)
        Sets the words supplying the parameter values for this environment.
        Parameters:
        words - list of words
      • getParamHelp

        public java.lang.String getParamHelp​(Parameter param)
        Returns the help string for a given parameter. This should be supplied in ready-to-use form, that is formatted for a suitable screen width etc.
        Parameters:
        param - parameter
        Returns:
        formatted documentation for param
      • isHidden

        public boolean isHidden​(Parameter param)
        Determines whether a parameter is "hidden", that is its value should not be revealed to prying eyes. The default implementation returns false.
        Parameters:
        param - param
        Returns:
        true if param is hidden type
      • checkParameters

        public void checkParameters​(Parameter[] params)
                             throws UsageException
        Checks that this environment's values are compatible with the given list of parameters. If any of the values does not appear to be a spcecification of one of the listed parameters a UsageException will be thrown.
        Parameters:
        params - parameter list
        Throws:
        UsageException
      • getNames

        public java.lang.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
      • setInteractive

        public void setInteractive​(boolean interactive)
        Sets whether we are running interactively or not. Only if this attribute is true will any attempt be made to prompt the user for responses etc. Default is true.
        Parameters:
        interactive - whether we are running interactively
      • getInteractive

        public boolean getInteractive()
        Determines whether we are running interactively. Only if this attribute is true will any attempt be made to prompt the user for responses etc. Default is true.
        Returns:
        whether we are running interactively
      • setPromptAll

        public void setPromptAll​(boolean prompt)
        Sets whether all parameters which haven't received explicit values on the command line should be prompted for. Default is false. Only makes sense if we're running interatively.
        Parameters:
        prompt - whether to prompt for everything
      • getPromptAll

        public boolean getPromptAll()
        Determines whether all parameters which haven't received explicit values on the command line should be prompted for. Default is false.
        Returns:
        whether to prompt for everything
      • 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
      • setOutputStream

        public void setOutputStream​(java.io.PrintStream out)
        Sets the destination stream for standard out.
        Parameters:
        out - output stream
      • setErrorStream

        public void setErrorStream​(java.io.PrintStream err)
        Sets the destination stream for standard error.
        Parameters:
        err - error stream
      • getOutputStream

        public java.io.PrintStream getOutputStream()
        Description copied from interface: Environment
        Returns an output stream into which text output from a task can be written. This would correspond to standard output for a terminal-based application.
        Specified by:
        getOutputStream in interface Environment
        Returns:
        a stream for text output
      • getErrorStream

        public java.io.PrintStream getErrorStream()
        Description copied from interface: Environment
        Returns an output stream into which error or logging output from a task can be written. This would correspodnd to standard error for a terminal-based application.
        Specified by:
        getErrorStream in interface Environment
        Returns:
        a stream for error output
      • acquireValue

        public void acquireValue​(Parameter param)
                          throws TaskException
        Description copied from interface: Environment
        Obtains a legal value for a given parameter from the environment and sets the parameter's value accordingly.

        This environment should obtain a value for the parameter par in whatever way it sees fit, and must then call par's Parameter.setValueFromString(uk.ac.starlink.task.Environment, java.lang.String) method so that the parameter knows what its new value is. If the setValueFromString call throws a ParameterValueException the environment may try to get another value (for instance by re-prompting the user) or may give up and re-throw the exception.

        Specified by:
        acquireValue in interface Environment
        Parameters:
        param - the Parameter whose value is to be obtained and set
        Throws:
        TaskException
      • getUnused

        public java.lang.String[] getUnused()
        Returns a string containing any words of the input argument list which were never queried by the application to find their value. Such unused words probably merit a warning, since they may for instance be misspelled versions of real parameters.
        Returns:
        array of unused words
      • getAssignments

        public java.lang.String[] getAssignments()
        Returns an array of strings, one for each parameter assignment which was actually used (via acquireValue(uk.ac.starlink.task.Parameter)) for this environment.
        Returns:
        array of parameter assignment strings
      • paramNameMatches

        public boolean paramNameMatches​(java.lang.String envName,
                                        Parameter param)
        Indicates whether a parameter name supplied from the environment is a reference to a given parameter.

        The implementation in the LineEnvironment class performs case-insensitive matching against the param.getName(). This behaviour may be overridden by subclasses to change the environment's behaviour.

        Parameters:
        envName - parameter name from environment
        param - parameter
        Returns:
        true iff envName is considered to name param