Source for javax.swing.text.DefaultFormatter

   1: /* DefaultFormatter.java --
   2: Copyright (C) 2005  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: package javax.swing.text;
  39: 
  40: import java.io.Serializable;
  41: import java.lang.reflect.Constructor;
  42: import java.text.ParseException;
  43: 
  44: import javax.swing.JFormattedTextField;
  45: 
  46: /**
  47:  * The <code>DefaultFormatter</code> is a concrete formatter for use in
  48:  * {@link JFormattedTextField}s.
  49:  *
  50:  * It can format arbitrary values by invoking
  51:  * their {@link Object#toString} method.
  52:  *
  53:  * In order to convert a String back to
  54:  * a value, the value class must provide a single argument constructor that
  55:  * takes a String object as argument value. If no such constructor is found,
  56:  * the String itself is passed back by #stringToValue.
  57:  *  
  58:  * @author Roman Kennke (roman@kennke.org)
  59:  */
  60: public class DefaultFormatter extends JFormattedTextField.AbstractFormatter
  61:   implements Cloneable, Serializable
  62: {
  63: 
  64:   /**
  65:    * A {@link DocumentFilter} that intercepts modification of the
  66:    * JFormattedTextField's Document and commits the value depending
  67:    * on the value of the <code>commitsOnValidEdit</code> property.
  68:    *
  69:    */
  70:   // FIXME: Handle allowsInvalid and overwriteMode properties
  71:   private class FormatterDocumentFilter
  72:     extends DocumentFilter
  73:   {
  74:     /**
  75:      * Invoked when text is removed from a text component.
  76:      *
  77:      * @param bypass the FilterBypass to use to mutate the document
  78:      * @param offset the start position of the modification
  79:      * @param length the length of the removed text
  80:      *
  81:      * @throws BadLocationException if offset or lenght are invalid in
  82:      *     the Document
  83:      */
  84:     public void remove(DocumentFilter.FilterBypass bypass, int offset,
  85:                         int length)
  86:       throws BadLocationException
  87:     {
  88:       super.remove(bypass, offset, length);
  89:       checkValidInput();
  90:       commitIfAllowed();
  91:     }
  92:     
  93:     /**
  94:      * Invoked when text is inserted into a text component.
  95:      *
  96:      * @param bypass the FilterBypass to use to mutate the document
  97:      * @param offset the start position of the modification
  98:      * @param text the inserted text
  99:      * @param attributes the attributes of the inserted text
 100:      *
 101:      * @throws BadLocationException if offset or lenght are invalid in
 102:      *     the Document
 103:      */
 104:     public void insertString(DocumentFilter.FilterBypass bypass, int offset,
 105:                               String text, AttributeSet attributes)
 106:       throws BadLocationException
 107:     {
 108:       if (overwriteMode == true)
 109:         replace(bypass, offset, text.length(), text, attributes);
 110:       else
 111:         super.insertString(bypass, offset, text, attributes);
 112:       checkValidInput();
 113:       commitIfAllowed();
 114:     }
 115: 
 116:     /**
 117:      * Invoked when text is replaced in a text component.
 118:      * 
 119:      * @param bypass the FilterBypass to use to mutate the document
 120:      * @param offset the start position of the modification
 121:      * @param length the length of the removed text
 122:      * @param text the inserted text
 123:      * @param attributes the attributes of the inserted text
 124:      *
 125:      * @throws BadLocationException if offset or lenght are invalid in
 126:      *     the Document
 127:      */
 128:     public void replace(DocumentFilter.FilterBypass bypass, int offset,
 129:                          int length, String text, AttributeSet attributes)
 130:       throws BadLocationException
 131:     {
 132:       super.replace(bypass, offset, length, text, attributes);
 133:       checkValidInput();
 134:       commitIfAllowed();
 135:     }
 136: 
 137:     /**
 138:      * Commits the value to the JTextTextField if the property
 139:      * <code>commitsOnValidEdit</code> is set to <code>true</code>.
 140:      */
 141:     private void commitIfAllowed()
 142:     {
 143:       if (commitsOnValidEdit == true)
 144:         try
 145:           {
 146:             getFormattedTextField().commitEdit();
 147:           }
 148:         catch (ParseException ex)
 149:           {
 150:             // ignore invalid edits
 151:           }
 152:     }
 153: 
 154:     /**
 155:      * Checks if the value in the input field is valid. If the
 156:      * property allowsInvalid is set to <code>false</code>, then
 157:      * the string in the input field is not allowed to be entered.
 158:      */
 159:     private void checkValidInput()
 160:     {
 161:       JFormattedTextField ftf = getFormattedTextField();
 162:       try
 163:         {
 164:           Object newval = stringToValue(ftf.getText());
 165:         }
 166:       catch (ParseException ex)
 167:         {
 168:           if (!allowsInvalid)
 169:             {
 170:               // roll back the input if invalid edits are not allowed
 171:               try
 172:                 {
 173:                   ftf.setText(valueToString(ftf.getValue()));
 174:                 }
 175:               catch (ParseException pe)
 176:                 {
 177:                   // if that happens, something serious must be wrong
 178:                   AssertionError ae;
 179:           ae = new AssertionError("values must be parseable");
 180:           ae.initCause(pe);
 181:           throw ae;
 182:                 }
 183:             }
 184:         }
 185:     }
 186:   }
 187: 
 188:   /** The serialization UID (compatible with JDK1.5). */
 189:   private static final long serialVersionUID = -355018354457785329L;
 190: 
 191:   /**
 192:    * Indicates if the value should be committed after every
 193:    * valid modification of the Document.
 194:    */
 195:   boolean commitsOnValidEdit;
 196: 
 197:   /**
 198:    * If <code>true</code> newly inserted characters overwrite existing
 199:    * values, otherwise insertion is done the normal way.
 200:    */
 201:   boolean overwriteMode;
 202: 
 203:   /**
 204:    * If <code>true</code> invalid edits are allowed for a limited
 205:    * time.
 206:    */
 207:   boolean allowsInvalid;
 208: 
 209:   /**
 210:    * The class that is used for values.
 211:    */
 212:   Class valueClass;
 213: 
 214:   /**
 215:    * Creates a new instance of <code>DefaultFormatter</code>.
 216:    */
 217:   public DefaultFormatter()
 218:   {
 219:     commitsOnValidEdit = false;
 220:     overwriteMode = true;
 221:     allowsInvalid = true;
 222:   }
 223: 
 224:   /**
 225:    * Installs the formatter on the specified {@link JFormattedTextField}.
 226:    *
 227:    * This method does the following things:
 228:    * <ul>
 229:    * <li>Display the value of #valueToString in the
 230:    *  <code>JFormattedTextField</code></li>
 231:    * <li>Install the Actions from #getActions on the <code>JTextField</code>
 232:    * </li>
 233:    * <li>Install the DocumentFilter returned by #getDocumentFilter</li>
 234:    * <li>Install the NavigationFilter returned by #getNavigationFilter</li>
 235:    * </ul>
 236:    *
 237:    * This method is typically not overridden by subclasses. Instead override
 238:    * one of the mentioned methods in order to customize behaviour.
 239:    *
 240:    * @param ftf the {@link JFormattedTextField} in which this formatter
 241:    *     is installed 
 242:    */
 243:   public void install(JFormattedTextField ftf)
 244:   {
 245:     super.install(ftf);
 246:   }
 247: 
 248:   /**
 249:    * Returns <code>true</code> if the value should be committed after
 250:    * each valid modification of the input field, <code>false</code> if
 251:    * it should never be committed by this formatter.
 252:    *
 253:    * @return the state of the <code>commitsOnValidEdit</code> property
 254:    *
 255:    * @see #setCommitsOnValidEdit
 256:    */
 257:   public boolean getCommitsOnValidEdit()
 258:   {
 259:     return commitsOnValidEdit;
 260:   }
 261: 
 262:   /**
 263:    * Sets the value of the <code>commitsOnValidEdit</code> property.
 264:    *
 265:    * @param commitsOnValidEdit the new state of the
 266:    *     <code>commitsOnValidEdit</code> property
 267:    *
 268:    * @see #getCommitsOnValidEdit
 269:    */
 270:   public void setCommitsOnValidEdit(boolean commitsOnValidEdit)
 271:   {
 272:     this.commitsOnValidEdit = commitsOnValidEdit;
 273:   }
 274: 
 275:   /**
 276:    * Returns the value of the <code>overwriteMode</code> property.
 277:    * If that is set to <code>true</code> then newly inserted characters
 278:    * overwrite existing values, otherwise the characters are inserted like
 279:    * normal. The default is <code>true</code>.
 280:    *
 281:    * @return the value of the <code>overwriteMode</code> property
 282:    */
 283:   public boolean getOverwriteMode()
 284:   {
 285:     return overwriteMode;
 286:   }
 287: 
 288:   /**
 289:    * Sets the value of the <code>overwriteMode</code> property.
 290:    * 
 291:    * If that is set to <code>true</code> then newly inserted characters
 292:    * overwrite existing values, otherwise the characters are inserted like
 293:    * normal. The default is <code>true</code>.
 294:    *
 295:    * @param overwriteMode the new value for the <code>overwriteMode</code>
 296:    *     property
 297:    */
 298:   public void setOverwriteMode(boolean overwriteMode)
 299:   {
 300:     this.overwriteMode = overwriteMode;
 301:   }
 302: 
 303:   /**
 304:    * Returns whether or not invalid edits are allowed or not. If invalid
 305:    * edits are allowed, the JFormattedTextField may temporarily contain invalid
 306:    * characters.
 307:    *
 308:    * @return the value of the allowsInvalid property
 309:    */
 310:   public boolean getAllowsInvalid()
 311:   {
 312:     return allowsInvalid;
 313:   }
 314: 
 315:   /**
 316:    * Sets the value of the <code>allowsInvalid</code> property.
 317:    *
 318:    * @param allowsInvalid the new value for the property
 319:    *
 320:    * @see #getAllowsInvalid()
 321:    */
 322:   public void setAllowsInvalid(boolean allowsInvalid)
 323:   {
 324:     this.allowsInvalid = allowsInvalid;
 325:   }
 326: 
 327:   /**
 328:    * Returns the class that is used for values. When Strings are converted
 329:    * back to values, this class is used to create new value objects.
 330:    *
 331:    * @return the class that is used for values
 332:    */
 333:   public Class<?> getValueClass()
 334:   {
 335:     return valueClass;
 336:   }
 337: 
 338:   /**
 339:    * Sets the class that is used for values.
 340:    *
 341:    * @param valueClass the class that is used for values
 342:    *
 343:    * @see #getValueClass()
 344:    */
 345:   public void setValueClass(Class<?> valueClass)
 346:   {
 347:     this.valueClass = valueClass;
 348:   }
 349: 
 350:   /**
 351:    * Converts a String (from the JFormattedTextField input) to a value.
 352:    * In order to achieve this, the formatter tries to instantiate an object
 353:    * of the class returned by #getValueClass() using a single argument
 354:    * constructor that takes a String argument. If such a constructor cannot
 355:    * be found, the String itself is returned.
 356:    *
 357:    * @param string the string to convert
 358:    *
 359:    * @return the value for the string
 360:    *
 361:    * @throws ParseException if the string cannot be converted into
 362:    *     a value object (e.g. invalid input)
 363:    */
 364:   public Object stringToValue(String string)
 365:     throws ParseException
 366:   {
 367:     Object value = string;
 368:     Class valueClass = getValueClass();
 369:     if (valueClass == null)
 370:       {
 371:         JFormattedTextField jft = getFormattedTextField();
 372:         if (jft != null)
 373:           valueClass = jft.getValue().getClass();
 374:       }
 375:     if (valueClass != null)
 376:       try
 377:         {
 378:           Constructor constr = valueClass.getConstructor
 379:                                              (new Class[]{String.class});
 380:           value = constr.newInstance(new Object[]{ string });
 381:         }
 382:       catch (NoSuchMethodException ex)
 383:         {
 384:           // leave value as string
 385:         }
 386:       catch (Exception ex)
 387:         {
 388:           throw new ParseException(string, 0);
 389:         }
 390:     return value;
 391:   }
 392: 
 393:   /**
 394:    * Converts a value object into a String. This is done by invoking the
 395:    * {@link Object#toString()} method on the value.
 396:    *
 397:    * @param value the value to be converted
 398:    *
 399:    * @return the string representation of the value
 400:    *
 401:    * @throws ParseException if the value cannot be converted
 402:    */
 403:   public String valueToString(Object value)
 404:     throws ParseException
 405:   {
 406:     if (value == null)
 407:       return "";
 408:     return value.toString();
 409:   }
 410: 
 411:   /**
 412:    * Creates and returns a clone of this DefaultFormatter.
 413:    *
 414:    * @return a clone of this object
 415:    *
 416:    * @throws CloneNotSupportedException not thrown here
 417:    */
 418:   public Object clone()
 419:     throws CloneNotSupportedException
 420:   {
 421:     return super.clone();
 422:   }
 423: 
 424:   /**
 425:    * Returns the DocumentFilter that is used to restrict input.
 426:    *
 427:    * @return the DocumentFilter that is used to restrict input
 428:    */
 429:   protected DocumentFilter getDocumentFilter()
 430:   {
 431:     return new FormatterDocumentFilter();
 432:   }
 433: }