Argument and options parser for java
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readme.md

Jargo

A tool to ease the handling of program arguments/options
Build Status

Maven Central

Most basic usage

import static se.softhouse.jargo.Arguments.*;
...
String[] args = {"--enable-logging", "--listen-port", "8090", "Hello"};

Argument<?> helpArgument = helpArgument("-h", "--help"); //Will throw when -h is encountered
Argument<Boolean> enableLogging = optionArgument("-l", "--enable-logging")
									.description("Output debug information to standard out").build();
Argument<String> greetingPhrase = stringArgument()
									.description("A greeting phrase to greet new connections with").build();
Argument<List<Integer>> ports = integerArgument("-p", "--listen-port")
									.defaultValue(8080)
									.description("The port clients should connect to.")
									.metaDescription("<port>")
									.limitTo(Range.closed(0, 65536))
									.repeated().build();

try
{
	ParsedArguments arguments = CommandLineParser.withArguments(greetingPhrase, enableLogging, ports)
													.andArguments(helpArgument)
													.parse(args);
													
	System.out.println("Logging enabled: " + arguments.get(enableLogging));
	System.out.println("Ports: " + arguments.get(ports));
	System.out.println("Greeting visitors with: " + arguments.get(greetingPhrase));
}
catch(ArgumentException exception)
{
	System.out.println(exception.getMessageAndUsage());
	System.exit(1);
}

For more examples see the Javadoc

Dependency

Jargo

 <dependency>
   <groupId>se.softhouse</groupId>
   <artifactId>jargo</artifactId>
   <version>0.4.4</version>
 </dependency>

Common-test (optional) Javadoc

 <dependency>
  <groupId>se.softhouse</groupId>
  <artifactId>common-test</artifactId>
  <version>0.4.4</version>

JDK compatiblity

JDK 6

Version <= 0.4.1 (used Guava)

JDK 8

From version 0.4.2 and onwards this library requires jdk 8 and Guava was removed as a dependency. This made this library even more lightweight (179K, no external dependencies). Especially useful as command line tools are often distributed, so the small file-size can be useful. If you want to go even further in reducing the filesize of your program, you can try out Proguard

Bugs/Questions

Stack Overflow

Issues

QA forum

Rationale

for writing yet another argument parsing library (see Is there a good command line argument parser for Java? for others)

  1. Because type-safety, immutability and readability matters

  2. Compared to annotation based solutions (like JCommander) jargo can be updated at runtime to support more arguments

  3. The generics on Argument gives you compile-time errors when switching types

    In JCommander:

    @Parameter(names = "-file", converter = FileConverter.class)  
    File file; //Oops, changing this to int would not work very well with FileConverter

    In jargo:

    Arguments.fileArgument("-file").parse("-file", "filename.txt").createNewFile();

    if fileArgument would change to being integerArgument, trying to call createNewFile() would generate a compile-time error

  4. Because JCommander doesn't support repeated arguments other than List<String>

    String[] args = {"--numbers", "5", "6", "--numbers", "3", "4"};  
    Argument<List<List<Integer>>> numbers = Arguments.integerArgument("--numbers").arity(2).repeated().build();
  5. Reflection makes it hard to analyze references to classes/methods and it often requires a granted suppressAccessChecks from the SecurityManager, this may not be wanted. No reflection is used in jargo.