Command Line Arguments Parser for Java
- Licensed under the Apache License, Version 2.0
- Supports *NIX style options
- Short options: -v
- Long options: --verbose
- Options with zero arguments (flags): -v
- Options with exact number of arguments: -p22 --port=22 --port 22 --sum=1;6
- Options with unlimited number of arguments
- Decisions/Alternatives (e.g. to support different commands)
- Keywords
- Nameless option
- Generified for type safety
- Custom type converters
- Imperative style (e.g. addOption, addFlag, ...)
- Annotations (@Option, @HelpCategory, ...)
- Annotations can be mixed with imperative style
- Mapping of arguments to nested data structures
- I18N for usage and error messages
- Customizable usage and help categories
- Since 3.0.0 support for JDK17
import de.hasait.clap.*;
public class BasicCLI {
public static void main(String[] args) {
CLAP clap = new CLAP();
CLAPValue<Boolean> verboseOption = clap.addFlag('v', "verbose", false, "Increase verbosity level");
CLAPValue<Boolean> helpOption = clap.addFlag('h', "help", false, "Print help", true);
CLAPResult result = clap.parse(args);
if (result.contains(helpOption)) {
clap.printUsageAndHelp(System.out);
return;
}
int verbosityLevel = result.getCount(verboseOption);
// TODO do something useful
}
}Example with two exclusive sets of options: One for acting as client and another one for acting as server.
import de.hasait.clap.*;
public class ClientServerCLI {
public static void main(String[] args) {
// Usage: [-v|--verbose] [-h|--help] { {-H|--host <host>} {-p|--port <port>} | {-l|--listen <port>} }
CLAP clap = new CLAP();
CLAPValue<Boolean> verboseOption = clap.addFlag('v', "verbose", false, "Increase verbosity level");
CLAPValue<Boolean> helpOption = clap.addFlag('h', "help", false, "Print help", true);
CLAPNode decision = clap.addDecision();
CLAPNode clientBranch = decision.addGroup();
clientBranch.setHelpCategory(2000, "Client");
CLAPValue<String> clientHost = clientBranch.addOption1(String.class, 'H', "host", true, "The host to connect to", "host");
CLAPValue<Integer> clientPort = clientBranch.addOption1(Integer.class, 'p', "port", true, "The port to connect to", "port");
CLAPNode serverBranch = decision.addGroup();
serverBranch.setHelpCategory(2001, "Server");
CLAPValue<Integer> serverPort = serverBranch.addOption1(Integer.class, 'l', "listen", true, "The port to listen on", "port");
CLAPResult result;
try {
result = clap.parse(args);
} catch (CLAPException e) {
clap.printUsageAndHelp(System.out);
throw e;
}
if (result.contains(helpOption)) {
clap.printUsageAndHelp(System.out);
return;
}
int verbosityLevel = result.getCount(verboseOption);
System.out.println("verbosityLevel=" + verbosityLevel);
if (result.contains(clientBranch)) {
System.out.println("Connecting to " + result.getValue(clientHost) + ":" + result.getValue(clientPort) + "...");
// TODO client
} else if (result.contains(serverBranch)) {
System.out.println("Listening on " + result.getValue(serverPort) + "...");
// TODO server
}
}
}Example program supporting two commands: Scale and rotate of provided files.
import de.hasait.clap.*;
public class CommandCLI {
public interface Command {
void execute(String[] files);
}
@CLAPKeyword("rotate")
public static class RotateCommand implements Command {
private boolean ccw;
public boolean isCcw() {
return ccw;
}
@CLAPOption(longKey = "ccw", descriptionNLSKey = "Rotate counterclockwise")
public void setCcw(boolean ccw) {
this.ccw = ccw;
}
@Override
public void execute(String[] files) {
System.out.println("rotate " + (ccw ? "ccw" : "cw") + ": " + Arrays.asList(files));
}
}
@CLAPKeyword("scale")
public static class ScaleCommand implements Command {
private int percent;
public int getPercent() {
return percent;
}
@CLAPOption(shortKey = 'p', longKey = "percent", required = true, descriptionNLSKey = "Scale percentage", argUsageNLSKey = "percent")
public void setPercent(int percent) {
this.percent = percent;
}
@Override
public void execute(String[] files) {
System.out.println("scale " + percent + "%: " + Arrays.asList(files));
}
}
public static class Args {
private Command command;
private String[] files;
public Command getCommand() {
return command;
}
@CLAPDecision(branches = {
ScaleCommand.class,
RotateCommand.class
})
public void setCommand(Command command) {
this.command = command;
}
public String[] getFiles() {
return files;
}
@CLAPOption(required = true, descriptionNLSKey = "Files to process", argUsageNLSKey = "file")
public void setFiles(String[] files) {
this.files = files;
}
}
public static void main(String[] rawArgs) {
CLAP clap = new CLAP();
CLAPValue<Boolean> verboseOption = clap.addFlag('v', "verbose", false, "Increase verbosity level");
CLAPValue<Boolean> helpOption = clap.addFlag('h', "help", false, "Print help", true);
CLAPValue<Args> argsClassOption = clap.addClass(Args.class);
CLAPResult result;
try {
result = clap.parse(rawArgs);
} catch (CLAPException e) {
clap.printUsageAndHelp(System.out);
throw e;
}
if (result.contains(helpOption)) {
clap.printUsageAndHelp(System.out);
return;
}
int verbosityLevel = result.getCount(verboseOption);
System.out.println("verbosityLevel=" + verbosityLevel);
Args args = result.getValue(argsClassOption);
args.getCommand().execute(args.files);
}
}Please have a look at the various tests. You will also find examples for annotation based parsing.