filevalidator.java

JAVA Servlet2.3外文书籍源码

package firewall.common;

/**
 * Title:        Professional Java Servlet Programming - Chapter 2
 * Description:  Class to provide common static utility methods
 * Copyright:    Copyright (c) 2001
 * Company:
 * @author Andrew Harbourne-Thomas
 * @version 1.0
 */

public class FileValidator
{
  /**
   * Provides a (limited) String array of valid
   *  character file extensions
   */
  public static final String[] VALID_EXTENSIONS =
              {"txt", "html", "htm", "java"};

  /**
   * This method is desinged to determine if the filename passed
   * is valid according to the following rules:
   *  filename cannot be null or empty,
   *  filename must end in a valid extension (as specified)
   *
   * @param filename - the filename to be checked
   * @return boolean indication if the filename is valid;
   *          true if it is, false otherwise.
   */
  public static boolean isFileNameValid(String filename)
  {
    if (filename == null || filename.length() == 0) {
      return false;
    }

    for (int i = 0; i < VALID_EXTENSIONS.length; i++)
    {
      if (filename.endsWith("." + VALID_EXTENSIONS[i])) {
        return true;
      }
    }
    return false;
  }

  /**
   * This method recieves a file list (String[]) and checks that all
   * files are valid names.  If not, it removes them (replaces with null).
   */
  public static void cleanFileList(String[] files)
  {
    for (int i = 0; i < files.length; i++)
    {
      if (!isFileNameValid(files[i])) {
        files[i] = null;
      }
    }
  }
}