package rmuir;

import java.text.ParseException;
import java.util.Objects;

/*
 * Copyright (c) 2015 Robert Muir. 
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/**
 * Boolean parser that does not suck.
 */
public final class BooleanParser {
  
  /**
   * Parses a boolean value, the way you would expect.
   * @param string text to parse. must be {@code true} or {@code false}.
   * @return parsed boolean value
   * @throws ParseException if {@code string} is something other than {@code true} or {@code false}.
   * @throws NullPointerException if {@code string} is {@code null}.
   */
  public static boolean parseBoolean(String string) throws ParseException {
    Objects.requireNonNull(string, "string argument must be non-null");
    switch (string) {
      case "true": return true;
      case "false": return false;
      default: throw new ParseException("Invalid boolean value: '" + string + "'", 0);
    }
  }
}

package rmuir;

import java.text.ParseException;
import java.util.Objects;

/*
 * Copyright (c) 2015 Robert Muir. 
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/**
 * Boolean parser that does not suck.
 */
public final class BooleanParser {
  
  /**
   * Parses a boolean value, the way you would expect.
   * @param string text to parse. must be {@code true} or {@code false}.
   * @return parsed boolean value
   * @throws ParseException if {@code string} is something other than {@code true} or {@code false}.
   * @throws NullPointerException if {@code string} is {@code null}.
   */
  public static boolean parseBoolean(String string) throws ParseException {
    Objects.requireNonNull(string, "String argument was null. Checking for null is too hard? Give up, programming is not for you.");
    switch (string) {
      case "true": return true;
      case "false": return false;
      default: throw new ParseException("Invalid boolean value: '" + string + "'", 0);
    }
  }
}

Make error message better