diff -r e417b37e6c08 -r f3b4caf1d05d java/copy-image-resizer/src/cz/frantovo/copyImageResizer/cli/CLIParser.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/java/copy-image-resizer/src/cz/frantovo/copyImageResizer/cli/CLIParser.java	Sun Nov 16 21:59:13 2014 +0100
@@ -0,0 +1,139 @@
+/**
+ * copy-image-resizer
+ * Copyright © 2014 František Kučera (frantovo.cz)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package cz.frantovo.copyImageResizer.cli;
+
+import java.io.File;
+import java.util.Arrays;
+import java.util.Collection;
+
+/**
+ *
+ * @author Ing. František Kučera (frantovo.cz)
+ */
+public class CLIParser {
+
+	public CLIOptions parseOptions(String[] args) throws CLIParserException {
+		CLIOptions options = new CLIOptions();
+
+		for (int i = 0; i < args.length; i++) {
+			String arg = args[i];
+
+			boolean matches = false;
+
+			for (Token t : Token.values()) {
+				if (t.matches(arg)) {
+					int parsedArgs = t.parse(args, i, options);
+					i = i + parsedArgs;
+					matches = true;
+				}
+			}
+
+			if (!matches) {
+				throw new CLIParserException("Unknown option: " + arg);
+			}
+		}
+
+		return options;
+	}
+
+	private static String fetchNext(String[] args, int index) throws CLIParserException {
+		if (index < args.length) {
+			return args[index];
+		} else {
+			throw new CLIParserException("Expecting value for option: " + args[index - 1]);
+		}
+	}
+
+	private static enum Token {
+
+		INPUT_DIR("--input-dir") { // bash-completion: option
+					@Override
+					public int parse(String[] args, int index, CLIOptions options) throws CLIParserException {
+						int originalIndex = index;
+						String name = fetchNext(args, ++index);
+						options.setInput(new File(name));
+						return index - originalIndex;
+					}
+				},
+		OUTPUT_DIR("--output-dir") { // bash-completion: option
+					@Override
+					public int parse(String[] args, int index, CLIOptions options) throws CLIParserException {
+						int originalIndex = index;
+						String name = fetchNext(args, ++index);
+						options.setOutput(new File(name));
+						return index - originalIndex;
+					}
+				},
+		SIZE("--size") { // bash-completion: option
+					@Override
+					public int parse(String[] args, int index, CLIOptions options) throws CLIParserException {
+						int originalIndex = index;
+						int width = parseInt(fetchNext(args, ++index));
+						int height = parseInt(fetchNext(args, ++index));
+						String directory = width + "x" + height;
+						options.addSize(new CLIOptions.SizeSpecification(width, height, directory));
+						return index - originalIndex;
+					}
+				},
+		SIZE_NAMED("--size-named") { // bash-completion: option
+					@Override
+					public int parse(String[] args, int index, CLIOptions options) throws CLIParserException {
+						int originalIndex = index;
+						int width = parseInt(fetchNext(args, ++index));
+						int height = parseInt(fetchNext(args, ++index));
+						String directory = fetchNext(args, ++index);
+						options.addSize(new CLIOptions.SizeSpecification(width, height, directory));
+						return index - originalIndex;
+					}
+				};
+
+		private final Collection<String> options;
+
+		private Token(String... options) {
+			this.options = Arrays.asList(options);
+		}
+
+		/**
+		 * @param option e.g. „--input-file“
+		 * @return whether option is this token
+		 */
+		public boolean matches(String option) {
+			return options.contains(option);
+		}
+
+		private static int parseInt(String number) throws CLIParserException {
+			try {
+				return Integer.parseInt(number);
+			} catch (Exception e) {
+				throw new CLIParserException("Unable to parse integer: " + number, e);
+			}
+		}
+
+		/**
+		 * Parse String arguments and fill values into the options object.
+		 *
+		 * @param args CLI arguments
+		 * @param index index of the option matched by this token, like „--input-file“
+		 * @param options object to be filled
+		 * @return number of parsed arguments – if option has no arguments (just boolean flag),
+		 * return 0, otherwise return positive integer: number of eaten arguments.
+		 * @throws CLIParserException
+		 */
+		public abstract int parse(String[] args, int index, CLIOptions options) throws CLIParserException;
+	}
+}