/*

 Wotonomy: OpenStep design patterns for pure Java applications.

 Copyright (C) 2000 Blacksmith, Inc.

 This library is free software; you can redistribute it and/or

 modify it under the terms of the GNU Lesser General Public

 License as published by the Free Software Foundation; either

 version 2.1 of the License, or (at your option) any later version.

 This library 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

 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public

 License along with this library; if not, see http://www.gnu.org

 */

 package net.wotonomy.ui.swing.components;

 import java.awt.datatransfer.DataFlavor;

 import java.awt.datatransfer.Transferable;

 import java.awt.datatransfer.UnsupportedFlavorException;

 import java.awt.event.KeyEvent;

 import javax.swing.JPasswordField;

 /**

  * SmartPasswordField is an extention of JPasswordField.  It does everything

  * a JPassword does, as well as limit the number of characters.  The user

  * of this class can specify that a password can only have a maximum of

  * 10 characters for instance.

  *

  * @author rob@straylight.princeton.com

  * @author $Author: cgruber $

  * @version $Revision: 904 $

  */

 public class SmartPasswordField extends JPasswordField

 {

 /*******************************

 * CONSTANTS

 *******************************/

    private static final int BACKSPACE = 8;

    private static final int DELETE = 127;

    private static final int SPACE = 32;

    private static final int DASH = 45;

    private static final int UNDERSCORE = 95;

    private static final int PERIOD = 46;

    private static final int PASTE = 22;  // Ctl-V

    private int passwordLength = Integer.MAX_VALUE;

 /*******************************

 * PUBLIC METHODS

 *******************************/

 /**

 * Default constructor.

 */

    public SmartPasswordField()

    {

        super();

    }

 /**

 * This constructor allows the user to set the maximum length of the password.

 * @param aLength The maximum length of the password.

 */

    public SmartPasswordField( int aLength )

    {

        this();

        setPasswordLength( aLength );

    }

 /**

 * Sets the maximum lenght of the password.  The value must be 0 or greater.

 * If the length specified is less than 0, then no action occurs.

 * @param aLength The maximum lenght of the password.

 */

     public void setPasswordLength( int aLength )

     {

         if ( aLength >= 0 )

         {

             passwordLength = aLength;

         }

     }

 /**

 * Returns the current maximum length of the password.

 * @return The current maximum length of the password.

 */

     public int getPasswordLength()

     {

         return passwordLength;

     }

 /**

 * This method processes a key event.  This event is generated by input from the

 * keyboard when this text field has the focus.  This method is called for every

 * key that is pressed and released on the keyboard.  This includes modifier

 * keys like the shift and alt keys.  This class looks at the key and determines

 * if the key is valid input given the restrictions of this class. <BR> <BR>

 * @param e A key event generated by a keyboard action.

 */

    public void processKeyEvent(KeyEvent e)

    {

       String currentText = "";

       String testString = "";

       char newChar = e.getKeyChar();

       int currentLength = 0;

       int selectionStart = 0;

       int selectionEnd = 0;

       int endOfHead = 0;

       int startOfTail = 0;

       boolean backspace = false;

       boolean delete = false;

       boolean paste = false;

       boolean insertionPoint = false;

       boolean selectionAtStart = false;

       boolean selectionAtEnd = false;

       backspace = (newChar == BACKSPACE);

       delete = (newChar == DELETE);

       paste = (newChar == PASTE);

       if ((e.getKeyCode() == KeyEvent.VK_UNDEFINED) || ((backspace) || (delete) || (paste)))  // A "key-typed" event

       {

          if (isValidCharacter(newChar))

          {

             if ((isPrintableCharacter(newChar)) || (backspace) || (delete) || (paste))

             {

                // Analyze the current contents of the field

                currentText = new String( getPassword() );

                currentLength = currentText.length();

                selectionStart = getSelectionStart();

                selectionEnd = getSelectionEnd();

                insertionPoint = (selectionStart == selectionEnd);

                selectionAtStart = (selectionStart == 0);

                selectionAtEnd = (selectionEnd >= currentLength);

                if (selectionEnd > currentLength)

                {

                   setSelectionEnd(currentLength);

                }

                // Generate new string

                if (selectionStart > 0) // Create head of test string

                {

                   endOfHead = selectionStart;

                   if (insertionPoint && backspace)

                   {

                      endOfHead -= 1;

                   }

                   testString += currentText.substring(0, endOfHead);

                }

                if (!(backspace || delete || paste))  // Add the new character

                {

                   testString += newChar;

                }

                if (paste)  // Add the string from the clipboard

                {

                   Transferable data = getToolkit().getSystemClipboard().getContents(this);

                   if (data != null)

                   {

                      try

                      {

                         String clipString = (String)data.getTransferData(DataFlavor.stringFlavor);

                         testString += clipString;

                      }

                      catch (java.io.IOException ioe)

                      {

                         // Do nothing

                      }

                      catch (UnsupportedFlavorException ufe)

                      {

                         // Do nothing

                      }

                   }

                }

                if (selectionEnd < currentLength) // Add the tail of the string

                {

                   startOfTail = selectionEnd;

                   if (insertionPoint && delete)

                   {

                      startOfTail += 1;

                   }

                   testString += currentText.substring(startOfTail);

                }

             }

             if (testString.compareTo("") != 0)  // Null string is OK

             {

                if (!(isValidString(testString)))

                {

                   e.consume();

                }

             }

          }

          else

          {

             e.consume();

          }

       }

       super.processKeyEvent(e);

       postProcessing();

    }

 /*******************************

 * PROTECTED METHODS

 *******************************/

 /**

 * Returns whether the inputted character is valid or not.  In this case all

 * characters are valid input.

 * @param aChar A character to perform the validity test with.

 * @return True if the character is valid for this subclassed text field. <BR>

 *         False is the character is not valid.

 */

    protected boolean isValidCharacter(char aChar)

    {

        return true;

    }

 /**

 * Returns whether a string is valid for this text field.  As the user types from

 * the keyboard, this method is called to determine if the new string in the text

 * field is valid based upon the restriction of this class.  The length of the

 * new string is checked against the maximum password length.

 * @param aString The string to perform the validity check with.

 * @return True if the length of the string is less than or equal to the maximum length.

 *         False if the character is not valud.

 */

    protected boolean isValidString(String aString)

    {

        if ( aString.length() > passwordLength )

        {

            return false;

        }

        return true;

    }

 /**

 * This class does not need any post processing.

 */

    protected void postProcessing()

    {

        /* Do Nothing */

    }

 /*******************************

 * PRIVATE METHODS

 *******************************/

    private boolean isPrintableCharacter(char inputChar)

    {

       if ((inputChar >= ' ') && (inputChar <= '~'))

       {

          return true;

       }

       return false;

    }

 }