joptsimple
Class OptionParser

java.lang.Object
  extended by joptsimple.OptionParser

public class OptionParser
extends java.lang.Object

Parses command line arguments, using a syntax that attempts to take from the best of POSIX getopt() and GNU getopt_long().

This parser supports short options and long options.

There are two ways to tell the parser what options to recognize:

  1. A "fluent interface"-style API for specifying options, available since version 2. Sentences in this fluent interface language begin with a call to accepts or acceptsAll methods; calls on the ensuing chain of objects describe whether the options can take an argument, whether the argument is required or optional, to what type arguments of the options should be converted if any, etc. Since version 3, these calls return an instance of OptionSpec, which can subsequently be used to retrieve the arguments of the associated option in a type-safe manner.
  2. Since version 1, a more concise way of specifying short options has been to use the special constructor. Arguments of options specified in this manner will be of type String. Here are the rules for the format of the specification strings this constructor accepts:

Each of the options in a list of options given to acceptsAll is treated as a synonym of the others. For example:

     
     OptionParser parser = new OptionParser();
     parser.acceptsAll( asList( "w", "interactive", "confirmation" ) );
     OptionSet options = parser.parse( "-w" );
     
   
In this case, options.has would answer true when given arguments "w", "interactive", and "confirmation". The OptionSet would give the same responses to these arguments for its other methods as well.

By default, as with GNU getopt(), the parser allows intermixing of options and non-options. If, however, the parser has been created to be "POSIX-ly correct", then the first argument that does not look lexically like an option, and is not a required argument of a preceding option, signals the end of options. You can still bind optional arguments to their options using the abutting (for short options) or = syntax.

Unlike GNU getopt(), this parser does not honor the environment variable POSIXLY_CORRECT. "POSIX-ly correct" parsers are configured by either:

  1. using the method posixlyCorrect(boolean), or
  2. using the constructor with an argument whose first character is a plus sign ("+")

Author:
Paul Holser
See Also:
The GNU C Library

Constructor Summary
OptionParser()
          Creates an option parser that initially recognizes no options, and does not exhibit "POSIX-ly correct" behavior.
OptionParser(java.lang.String optionSpecification)
          Creates an option parser and configures it to recognize the short options specified in the given string.
 
Method Summary
 OptionSpecBuilder accepts(java.lang.String option)
          Tells the parser to recognize the given option.
 OptionSpecBuilder accepts(java.lang.String option, java.lang.String description)
          Tells the parser to recognize the given option.
 OptionSpecBuilder acceptsAll(java.util.Collection<java.lang.String> options)
          Tells the parser to recognize the given options, and treat them as synonymous.
 OptionSpecBuilder acceptsAll(java.util.Collection<java.lang.String> options, java.lang.String description)
          Tells the parser to recognize the given options, and treat them as synonymous.
 OptionSet parse(java.lang.String... arguments)
          Parses the given command line arguments according to the option specifications given to the parser.
 void posixlyCorrect(boolean setting)
          Tells the parser whether or not to behave "POSIX-ly correct"-ly.
 void printHelpOn(java.io.OutputStream sink)
          Writes information about the options this parser recognizes to the given output sink.
 void printHelpOn(java.io.Writer sink)
          Writes information about the options this parser recognizes to the given output sink.
 void recognizeAlternativeLongOptions(boolean recognize)
          Tells the parser either to recognize or ignore "-W"-style long options.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

OptionParser

public OptionParser()

Creates an option parser that initially recognizes no options, and does not exhibit "POSIX-ly correct" behavior.


OptionParser

public OptionParser(java.lang.String optionSpecification)

Creates an option parser and configures it to recognize the short options specified in the given string.

Arguments of options specified this way will be of type String.

Parameters:
optionSpecification - an option specification
Throws:
java.lang.NullPointerException - if optionSpecification is null
OptionException - if the option specification contains illegal characters or otherwise cannot be recognized
Method Detail

accepts

public OptionSpecBuilder accepts(java.lang.String option)

Tells the parser to recognize the given option.

This method returns an instance of OptionSpecBuilder to allow the formation of parser directives as sentences in a fluent interface language. For example:


   OptionParser parser = new OptionParser();
   parser.accepts( "c" ).withRequiredArg().ofType( Integer.class );
 

If no methods are invoked on the returned OptionSpecBuilder, then the parser treats the option as accepting no argument.

Parameters:
option - the option to recognize
Returns:
an object that can be used to flesh out more detail about the option
Throws:
OptionException - if the option contains illegal characters
java.lang.NullPointerException - if the option is null

accepts

public OptionSpecBuilder accepts(java.lang.String option,
                                 java.lang.String description)

Tells the parser to recognize the given option.

Parameters:
option - the option to recognize
description - a string that describes the purpose of the option. This is used when generating help information about the parser.
Returns:
an object that can be used to flesh out more detail about the option
Throws:
OptionException - if the option contains illegal characters
java.lang.NullPointerException - if the option is null
See Also:
accepts(String)

acceptsAll

public OptionSpecBuilder acceptsAll(java.util.Collection<java.lang.String> options)

Tells the parser to recognize the given options, and treat them as synonymous.

Parameters:
options - the options to recognize and treat as synonymous
Returns:
an object that can be used to flesh out more detail about the options
Throws:
OptionException - if any of the options contain illegal characters
java.lang.NullPointerException - if the option list or any of its elements are null
See Also:
accepts(String)

acceptsAll

public OptionSpecBuilder acceptsAll(java.util.Collection<java.lang.String> options,
                                    java.lang.String description)

Tells the parser to recognize the given options, and treat them as synonymous.

Parameters:
options - the options to recognize and treat as synonymous
description - a string that describes the purpose of the option. This is used when generating help information about the parser.
Returns:
an object that can be used to flesh out more detail about the options
Throws:
OptionException - if any of the options contain illegal characters
java.lang.NullPointerException - if the option list or any of its elements are null
java.lang.IllegalArgumentException - if the option list is empty
See Also:
acceptsAll(Collection)

posixlyCorrect

public void posixlyCorrect(boolean setting)

Tells the parser whether or not to behave "POSIX-ly correct"-ly.

Parameters:
setting - true if the parser should behave "POSIX-ly correct"-ly

recognizeAlternativeLongOptions

public void recognizeAlternativeLongOptions(boolean recognize)

Tells the parser either to recognize or ignore "-W"-style long options.

Parameters:
recognize - true if the parser is to recognize the special style of long options

printHelpOn

public void printHelpOn(java.io.OutputStream sink)
                 throws java.io.IOException

Writes information about the options this parser recognizes to the given output sink.

The output sink is flushed, but not closed.

Parameters:
sink - the sink to write information to
Throws:
java.io.IOException - if there is a problem writing to the sink
java.lang.NullPointerException - if sink is null
See Also:
printHelpOn(Writer)

printHelpOn

public void printHelpOn(java.io.Writer sink)
                 throws java.io.IOException

Writes information about the options this parser recognizes to the given output sink.

The output sink is flushed, but not closed.

Parameters:
sink - the sink to write information to
Throws:
java.io.IOException - if there is a problem writing to the sink
java.lang.NullPointerException - if sink is null
See Also:
printHelpOn(OutputStream)

parse

public OptionSet parse(java.lang.String... arguments)

Parses the given command line arguments according to the option specifications given to the parser.

Parameters:
arguments - arguments to parse
Returns:
an OptionSet describing the parsed options, their arguments, and any non-option arguments found
Throws:
OptionException - if problems are detected while parsing
java.lang.NullPointerException - if the argument list is null


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