Source for javax.swing.text.PasswordView

   1: /* PasswordView.java -- 
   2:  Copyright (C) 2004 Free Software Foundation, Inc.
   3: 
   4:  This file is part of GNU Classpath.
   5: 
   6:  GNU Classpath is free software; you can redistribute it and/or modify
   7:  it under the terms of the GNU General Public License as published by
   8:  the Free Software Foundation; either version 2, or (at your option)
   9:  any later version.
  10: 
  11:  GNU Classpath is distributed in the hope that it will be useful, but
  12:  WITHOUT ANY WARRANTY; without even the implied warranty of
  13:  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14:  General Public License for more details.
  15: 
  16:  You should have received a copy of the GNU General Public License
  17:  along with GNU Classpath; see the file COPYING.  If not, write to the
  18:  Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19:  02110-1301 USA.
  20: 
  21:  Linking this library statically or dynamically with other modules is
  22:  making a combined work based on this library.  Thus, the terms and
  23:  conditions of the GNU General Public License cover the whole
  24:  combination.
  25: 
  26:  As a special exception, the copyright holders of this library give you
  27:  permission to link this library with independent modules to produce an
  28:  executable, regardless of the license terms of these independent
  29:  modules, and to copy and distribute the resulting executable under
  30:  terms of your choice, provided that you also meet, for each linked
  31:  independent module, the terms and conditions of the license of that
  32:  module.  An independent module is a module which is not derived from
  33:  or based on this library.  If you modify this library, you may extend
  34:  this exception to your version of the library, but you are not
  35:  obligated to do so.  If you do not wish to do so, delete this
  36:  exception statement from your version. */
  37: 
  38: 
  39: package javax.swing.text;
  40: 
  41: import java.awt.Color;
  42: import java.awt.FontMetrics;
  43: import java.awt.Graphics;
  44: import java.awt.Shape;
  45: 
  46: import javax.swing.JPasswordField;
  47: 
  48: public class PasswordView
  49:   extends FieldView
  50: {
  51:   /**
  52:    * Buffer for putting the echo char into it and
  53:    * then using it to draw it into the view.
  54:    */
  55:   private char[] oneCharBuffer = new char[1];
  56: 
  57:   public PasswordView(Element elem)
  58:   {
  59:     super(elem);
  60:   }
  61: 
  62:   /**
  63:    * Draws one echo character at a given position.
  64:    *
  65:    * @param g the <code>Graphics</code> object to draw to
  66:    * @param x the x-position
  67:    * @param y the y-position
  68:    * @param ch the echo character
  69:    *
  70:    * @return the next x position right of the drawn character
  71:    */
  72:   protected int drawEchoCharacter(Graphics g, int x, int y, char ch)
  73:   {
  74:     // Update font metrics.
  75:     updateMetrics();
  76: 
  77:     // Draw character.
  78:     oneCharBuffer[0] = ch;
  79:     g.drawChars(oneCharBuffer, 0, 1, x, y);
  80: 
  81:     // Return new x position right of drawn character.
  82:     return x + metrics.charWidth(ch);
  83:   }
  84: 
  85:   private char getEchoChar()
  86:   {
  87:     char ch = ((JPasswordField) getContainer()).getEchoChar();
  88: 
  89:     if (ch == 0)
  90:       ch = '*';
  91: 
  92:     return ch;
  93:   }
  94: 
  95:   /**
  96:    * Draws selected text at a given position.
  97:    *
  98:    * @param g the <code>Graphics</code> object to draw to
  99:    * @param x the x-position
 100:    * @param y the y-position
 101:    * @param p0 the position of the first character to draw
 102:    * @param p1 the position of the first character not to draw
 103:    *
 104:    * @return the next x position right of the drawn character
 105:    */
 106:   protected int drawSelectedText(Graphics g, int x, int y, int p0, int p1)
 107:     throws BadLocationException
 108:   {
 109:     // FIXME: Throw BadLocationException somehow.
 110: 
 111:     // Update font metrics.
 112:     updateMetrics();
 113: 
 114:     // Get echo character.
 115:     char ch = getEchoChar();
 116: 
 117:     // Set color for selected text.
 118:     g.setColor(selectedColor);
 119:     g.setColor(Color.BLACK);
 120: 
 121:     // Initialize buffer for faster drawing of all characters.
 122:     int len = p1 - p0;
 123:     char[] buffer = new char[len];
 124:     for (int index = 0; index < len; ++index)
 125:       buffer[index] = ch;
 126: 
 127:     // Draw echo charaters.
 128:     g.drawChars(buffer, 0, len, x, y);
 129: 
 130:     // Return new x position right of all drawn characters.
 131:     return x + len * metrics.charWidth(ch);
 132:   }
 133: 
 134:   /**
 135:    * Draws unselected text at a given position.
 136:    *
 137:    * @param g the <code>Graphics</code> object to draw to
 138:    * @param x the x-position
 139:    * @param y the y-position
 140:    * @param p0 the position of the first character to draw
 141:    * @param p1 the position of the first character not to draw
 142:    *
 143:    * @return the next x position right of the drawn character
 144:    */
 145:   protected int drawUnselectedText(Graphics g, int x, int y, int p0, int p1)
 146:     throws BadLocationException
 147:   {
 148:     // FIXME: Throw BadLocationException somehow.
 149: 
 150:     // Update font metrics.
 151:     updateMetrics();
 152: 
 153:     // Get echo character.
 154:     char ch = getEchoChar();
 155:     Segment segment = new Segment();
 156: 
 157:     // Set color for unselected text.
 158:     g.setColor(unselectedColor);
 159:     g.setColor(Color.BLACK);
 160: 
 161:     // Initialize buffer for faster drawing of all characters.
 162:     p1--;
 163:     getDocument().getText(p0, p1 - p0, segment);
 164:     int len = segment.toString().length();
 165:     
 166:     char[] buffer = new char[len];
 167:     for (int index = 0; index < len; ++index)
 168:       buffer[index] = ch;
 169:     
 170:     y += getPreferredSpan(Y_AXIS)/2;
 171:     
 172:     // Draw echo charaters.
 173:     g.drawChars(buffer, 0, len, x, y);
 174:     
 175:     // Return new x position right of all drawn characters.
 176:     return x + (len * metrics.charWidth(ch));
 177:   }
 178: 
 179:   /**
 180:    * Determines the preferred span for this view along an axis.
 181:    * 
 182:    * @param axis to get the preferred span of
 183:    * @return the preferred span of the axis
 184:    */
 185:   public float getPreferredSpan(int axis)
 186:   {
 187:     if (axis != X_AXIS && axis != Y_AXIS)
 188:       throw new IllegalArgumentException();
 189: 
 190:     FontMetrics fm = getFontMetrics();
 191: 
 192:     if (axis == Y_AXIS)
 193:         return fm.getHeight();
 194: 
 195:     String text;
 196:     Element elem = getElement();
 197: 
 198:     try
 199:       {
 200:         text = elem.getDocument().getText(elem.getStartOffset(),
 201:                                           elem.getEndOffset());
 202:       }
 203:     catch (BadLocationException e)
 204:       {
 205:         // This should never happen.
 206:         text = "";
 207:       }
 208:     return fm.stringWidth(text);
 209:   }
 210: 
 211:   /**
 212:    * Provides a mapping from the document model coordinate space to the
 213:    * coordinate space of the view mapped to it.
 214:    * 
 215:    * @param pos - the position to convert >= 0
 216:    * @param a - the allocated region to render into
 217:    * @param b - typesafe enumeration to indicate bias to a position in the model.
 218:    * @return the bounding box of the given position
 219:    * @throws BadLocationException if the given position does not 
 220:    * represent a valid location in the associated document
 221:    */
 222:   public Shape modelToView(int pos, Shape a, Position.Bias b)
 223:     throws BadLocationException
 224:   {
 225:     return super.modelToView(pos, a, b);
 226:   }
 227: 
 228:   /**
 229:    * Provides a mapping from the view coordinate space to the logical 
 230:    * coordinate space of the model.
 231:    * 
 232:    * @param fx - the X coordinate >= 0.0f
 233:    * @param fy - the Y coordinate >= 0.0f
 234:    * @param a - the allocated region to render into 
 235:    * @param bias - typesafe enumeration to indicate bias to a position in the model.
 236:    * @return the location within the model that best represents 
 237:    * the given point in the view
 238:    * 
 239:    */
 240:   public int viewToModel(float fx, float fy, Shape a, Position.Bias[] bias)
 241:   {
 242:     return super.viewToModel(fx, fy, a, bias);
 243:   }
 244: }