Java main arguments parser

MainArguments.java

import java.util.List;
import java.util.Map;
import java.util.Set;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;

/**
 * Parses options and arguments provided in the command line. All option values must be preceded with "--"
 * Example of use: 
 * 
 * MainArguments margs = new MainArguments(new String[] { "--port", "--user" }, args);
 * String port = margs.getOptionAsString("--port", "8080");
 * String user = margs.getOptionAsString("--user", "foobar");
 * 
 * @author icoloma
 *
 */
public class MainArguments {
	
	/** Map of options provided in the command line */
	private static Map<String, String> options = Maps.newHashMap();
	
	/** List with all remaining command line args */
	private List<String> remainderArgs = Lists.newArrayList();
	
	/**
	 * @param validOptions the list of options that are supported by this aplication
	 * @param cmdArgs the array of arguments passed by the command line
	 */
	public MainArguments(String[] validOptions, String[] cmdArgs) {
		Set<String> vo = Sets.newHashSet(validOptions);
		for (int i = 0; i < cmdArgs.length; ) {
			String arg = cmdArgs[i++];
			if (arg.startsWith("-")) {
				if (!vo.contains(arg)) {
					throw new IllegalArgumentException("Unexpected option: " + arg);
				}
				if (i >= cmdArgs.length) {
					throw new IllegalArgumentException("Missing value for " + arg);
				}
				options.put(arg, cmdArgs[i++]);
			} else {
				remainderArgs.add(arg);
			}
		}
	}
	
	/**
	 * Return the value of the provided option
	 * @param name the name of the option
	 * @param defaultValue the value to return if null
	 */
	public String getOptionAsString(String name, String defaultValue) {
		String value = options.get(name);
		return value == null? defaultValue : value;
	}
	
	public Integer getOptionAsInteger(String name, Integer defaultValue) {
		String value = options.get(name);
		return value == null? defaultValue : Integer.parseInt(value, 10);
	}

	public List<String> getRemainderArgs() {
		return remainderArgs;
	}

}

MainArgumentsTest.java

import static org.junit.Assert.assertEquals;

import org.junit.Test;

public class MainArgumentsTest {

	@Test
	public void testParseOptions() {
		MainArguments args = new MainArguments(
				new String[] { "--foo", "--bar" }, 
				new String[] { "--foo", "fooValue", "bazziebazbaz" }
				);
		assertEquals("fooValue", args.getOptionAsString("--foo", "xxx"));
		assertEquals("barDefaults", args.getOptionAsString("--bar", "barDefaults"));
		assertEquals(1, args.getRemainderArgs().size());
		assertEquals("bazziebazbaz", args.getRemainderArgs().get(0));
	}
	
	@Test(expected=IllegalArgumentException.class)
	public void testMissingOption() {
		new MainArguments(
				new String[] { "--foo", "--bar" }, 
				new String[] { "--foo" }
				);
	}
	
	@Test(expected=IllegalArgumentException.class)
	public void testIllegalOption() {
		new MainArguments(
				new String[] { "--foo", "--bar" }, 
				new String[] { "--xxx" }
				);
	}
	
}