Utility methods for ASCII character checking. : Character Data Type « Data Type « Java Tutorial

1. Java Tutorial
2. Data Type
3. Character Data Type

/**
 * Utility methods for ASCII character checking.
 */
public class ASCIIUtil {

  /**
   * Checks whether the supplied character is a letter or number.
   */
  public static boolean isLetterOrNumber(int c) {
    return isLetter(c) || isNumber(c);
  }

  /**
   * Checks whether the supplied character is a letter.
   */
  public static boolean isLetter(int c) {
    return isUpperCaseLetter(c) || isLowerCaseLetter(c);
  }

  /**
   * Checks whether the supplied character is an upper-case letter.
   */
  public static boolean isUpperCaseLetter(int c) {
    return (c >= 65 && c <= 90); // A - Z
  }

  /**
   * Checks whether the supplied character is an lower-case letter.
   */
  public static boolean isLowerCaseLetter(int c) {
    return (c >= 97 && c <= 122);  // a - z
  }

  /**
   * Checks whether the supplied character is a number
   */
  public static boolean isNumber(int c) {
    return (c >= 48 && c <= 57); // 0 - 9
  }
}