I am writing a Java application that takes command line arguments which are processed using Apache Commons CLI with the GnuParser. For reasons that are not interesting to get into, I would like it to silently ignore unknown command line options instead of throwing a ParseException but I don't see a way to do that. I see that there is a stopAtNonOption boolean option on GnuParser.parse() but what I want is more like ignoreAtNonOption where it will keep processing options after encountering an unknown token.
I could implement 开发者_运维百科my own parser to accomplish this but I'm surprised there isn't this functionality built in so I thought I'd check before going down that road.
Example code for what I'm talking about:
try {
CommandLine commandLine = parser.parse(options, args);
// stopAtNonOption set to true (below) is also not what I want
// CommandLine commandLine = parser.parse(options, args, true);
} catch (ParseException e) {
LOG.error("error parsing arguments", e);
throw new RuntimeException(e);
}
This works for me (other parsers can be derived, too):
public class ExtendedGnuParser extends GnuParser {
private boolean ignoreUnrecognizedOption;
public ExtendedGnuParser(final boolean ignoreUnrecognizedOption) {
this.ignoreUnrecognizedOption = ignoreUnrecognizedOption;
}
@Override
protected void processOption(final String arg, final ListIterator iter) throws ParseException {
boolean hasOption = getOptions().hasOption(arg);
if (hasOption || !ignoreUnrecognizedOption) {
super.processOption(arg, iter);
}
}
}
As mentioned in a comment, the accepted solution is no more suitable because the processOption
method has been deprecated and removed.
Here's my solution:
public class ExtendedParser extends DefaultParser {
private final ArrayList<String> notParsedArgs = new ArrayList<>();
public String[] getNotParsedArgs() {
return notParsedArgs.toArray(new String[notParsedArgs.size()]);
}
@Override
public CommandLine parse(Options options, String[] arguments, boolean stopAtNonOption) throws ParseException {
if(stopAtNonOption) {
return parse(options, arguments);
}
List<String> knownArguments = new ArrayList<>();
notParsedArgs.clear();
boolean nextArgument = false;
for (String arg : arguments) {
if (options.hasOption(arg) || nextArgument) {
knownArguments.add(arg);
} else {
notParsedArgs.add(arg);
}
nextArgument = options.hasOption(arg) && options.getOption(arg).hasArg();
}
return super.parse(options, knownArguments.toArray(new String[knownArguments.size()]));
}
}
Compared with the solution proposed by Pascal, it also checks for options with arguments and it keeps not parsed args in a separate list.
This is not possible with Commons CLI. But there may be another way to achieve the result you expect if you give more details of your use case.
I am a very bad developer, and I do this to break the code:
public class EasyPosixParser extends PosixParser {
@Override
protected void processOption(String arg, ListIterator iter) throws ParseException
{
try {
super.processOption(arg, iter);
} catch (ParseException e) {
// do nothing
}
}
}
in your main code, you do:
CommandLineParser commandlineParser = new EasyPosixParser();
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