Source for javax.swing.text.CompositeView

   1: /* CompositeView.java -- An abstract view that manages child views
   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: 
  39: package javax.swing.text;
  40: 
  41: import java.awt.Insets;
  42: import java.awt.Rectangle;
  43: import java.awt.Shape;
  44: 
  45: import javax.swing.SwingConstants;
  46: 
  47: /**
  48:  * An abstract base implementation of {@link View} that manages child
  49:  * <code>View</code>s.
  50:  *
  51:  * @author Roman Kennke (roman@kennke.org)
  52:  */
  53: public abstract class CompositeView
  54:   extends View
  55: {
  56: 
  57:   /**
  58:    * The child views of this <code>CompositeView</code>.
  59:    */
  60:   View[] children;
  61: 
  62:   /**
  63:    * The allocation of this <code>View</code> minus its insets. This is
  64:    * initialized in {@link #getInsideAllocation} and reused and modified in
  65:    * {@link #childAllocation(int, Rectangle)}.
  66:    */
  67:   Rectangle insideAllocation;
  68: 
  69:   /**
  70:    * The insets of this <code>CompositeView</code>. This is initialized
  71:    * in {@link #setInsets}.
  72:    */
  73:   Insets insets;
  74: 
  75:   /**
  76:    * Creates a new <code>CompositeView</code> for the given
  77:    * <code>Element</code>.
  78:    *
  79:    * @param element the element that is rendered by this CompositeView
  80:    */
  81:   public CompositeView(Element element)
  82:   {
  83:     super(element);
  84:     children = new View[0];
  85:     insets = new Insets(0, 0, 0, 0);
  86:   }
  87: 
  88:   /**
  89:    * Loads the child views of this <code>CompositeView</code>. This method
  90:    * is called from {@link #setParent} to initialize the child views of
  91:    * this composite view.
  92:    *
  93:    * @param f the view factory to use for creating new child views
  94:    *
  95:    * @see #setParent
  96:    */
  97:   protected void loadChildren(ViewFactory f)
  98:   {
  99:     Element el = getElement();
 100:     int count = el.getElementCount();
 101:     View[] newChildren = new View[count];
 102:     for (int i = 0; i < count; ++i)
 103:       {
 104:         Element child = el.getElement(i);
 105:         View view = f.create(child);
 106:         newChildren[i] = view;
 107:       }
 108:     replace(0, getViewCount(), newChildren);
 109:   }
 110: 
 111:   /**
 112:    * Sets the parent of this <code>View</code>.
 113:    * In addition to setting the parent, this calls {@link #loadChildren}, if
 114:    * this <code>View</code> does not already have its children initialized.
 115:    *
 116:    * @param parent the parent to set
 117:    */
 118:   public void setParent(View parent)
 119:   {
 120:     super.setParent(parent);
 121:     if (parent != null && ((children == null) || children.length == 0))
 122:       loadChildren(getViewFactory());
 123:   }
 124: 
 125:   /**
 126:    * Returns the number of child views.
 127:    *
 128:    * @return the number of child views
 129:    */
 130:   public int getViewCount()
 131:   {
 132:     return children.length;
 133:   }
 134: 
 135:   /**
 136:    * Returns the child view at index <code>n</code>.
 137:    *
 138:    * @param n the index of the requested child view
 139:    *
 140:    * @return the child view at index <code>n</code>
 141:    */
 142:   public View getView(int n)
 143:   {
 144:     return children[n];
 145:   }
 146: 
 147:   /**
 148:    * Replaces child views by some other child views. If there are no views to
 149:    * remove (<code>length == 0</code>), the result is a simple insert, if
 150:    * there are no children to add (<code>view == null</code>) the result
 151:    * is a simple removal.
 152:    *
 153:    * @param offset the start offset from where to remove children
 154:    * @param length the number of children to remove
 155:    * @param views the views that replace the removed children
 156:    */
 157:   public void replace(int offset, int length, View[] views)
 158:   {
 159:     // Check for null views to add.
 160:     for (int i = 0; i < views.length; ++i)
 161:       if (views[i] == null)
 162:         throw new NullPointerException("Added views must not be null");
 163: 
 164:     int endOffset = offset + length;
 165: 
 166:     // First we set the parent of the removed children to null.
 167:     for (int i = offset; i < endOffset; ++i)
 168:       children[i].setParent(null);
 169: 
 170:     View[] newChildren = new View[children.length - length + views.length];
 171:     System.arraycopy(children, 0, newChildren, 0, offset);
 172:     System.arraycopy(views, 0, newChildren, offset, views.length);
 173:     System.arraycopy(children, offset + length, newChildren,
 174:                      offset + views.length,
 175:                      children.length - (offset + length));
 176:     children = newChildren;
 177: 
 178:     // Finally we set the parent of the added children to this.
 179:     for (int i = 0; i < views.length; ++i)
 180:       views[i].setParent(this);
 181:   }
 182: 
 183:   /**
 184:    * Returns the allocation for the specified child <code>View</code>.
 185:    *
 186:    * @param index the index of the child view
 187:    * @param a the allocation for this view
 188:    *
 189:    * @return the allocation for the specified child <code>View</code>
 190:    */
 191:   public Shape getChildAllocation(int index, Shape a)
 192:   {
 193:     Rectangle r = getInsideAllocation(a);
 194:     childAllocation(index, r);
 195:     return r;
 196:   }
 197: 
 198:   /**
 199:    * Maps a position in the document into the coordinate space of the View.
 200:    * The output rectangle usually reflects the font height but has a width
 201:    * of zero.
 202:    *
 203:    * @param pos the position of the character in the model
 204:    * @param a the area that is occupied by the view
 205:    * @param bias either {@link Position.Bias#Forward} or
 206:    *        {@link Position.Bias#Backward} depending on the preferred
 207:    *        direction bias. If <code>null</code> this defaults to
 208:    *        <code>Position.Bias.Forward</code>
 209:    *
 210:    * @return a rectangle that gives the location of the document position
 211:    *         inside the view coordinate space
 212:    *
 213:    * @throws BadLocationException if <code>pos</code> is invalid
 214:    * @throws IllegalArgumentException if b is not one of the above listed
 215:    *         valid values
 216:    */
 217:   public Shape modelToView(int pos, Shape a, Position.Bias bias)
 218:     throws BadLocationException
 219:   {
 220:     int childIndex = getViewIndex(pos, bias);
 221:     if (childIndex != -1)
 222:       {
 223:         View child = getView(childIndex);
 224:         Rectangle r = a.getBounds();
 225:         childAllocation(childIndex, r);
 226:         Shape result = child.modelToView(pos, r, bias);
 227:         if (result == null)
 228:           throw new AssertionError("" + child.getClass().getName()
 229:                                    + ".modelToView() must not return null");
 230:         return result;
 231:       }
 232:     else
 233:       throw new BadLocationException("No child view for the specified location",
 234:                                      pos);
 235:   }
 236: 
 237:   /**
 238:    * Maps a region in the document into the coordinate space of the View.
 239:    *
 240:    * @param p1 the beginning position inside the document
 241:    * @param b1 the direction bias for the beginning position
 242:    * @param p2 the end position inside the document
 243:    * @param b2 the direction bias for the end position
 244:    * @param a the area that is occupied by the view
 245:    *
 246:    * @return a rectangle that gives the span of the document region
 247:    *         inside the view coordinate space
 248:    *
 249:    * @throws BadLocationException if <code>p1</code> or <code>p2</code> are
 250:    *         invalid
 251:    * @throws IllegalArgumentException if b1 or b2 is not one of the above
 252:    *         listed valid values
 253:    */
 254:   public Shape modelToView(int p1, Position.Bias b1,
 255:                int p2, Position.Bias b2, Shape a)
 256:     throws BadLocationException
 257:   {
 258:     // TODO: This is most likely not 100% ok, figure out what else is to
 259:     // do here.
 260:     return super.modelToView(p1, b1, p2, b2, a);
 261:   }
 262: 
 263:   /**
 264:    * Maps coordinates from the <code>View</code>'s space into a position
 265:    * in the document model.
 266:    *
 267:    * @param x the x coordinate in the view space, x >= 0
 268:    * @param y the y coordinate in the view space, y >= 0
 269:    * @param a the allocation of this <code>View</code>
 270:    * @param b the bias to use
 271:    *
 272:    * @return the position in the document that corresponds to the screen
 273:    *         coordinates <code>x, y</code> >= 0
 274:    */
 275:   public int viewToModel(float x, float y, Shape a, Position.Bias[] b)
 276:   {
 277:     if (x >= 0 && y >= 0)
 278:       {
 279:         Rectangle r = getInsideAllocation(a);
 280:         View view = getViewAtPoint((int) x, (int) y, r);
 281:         return view.viewToModel(x, y, a, b);
 282:       }
 283:     return 0;
 284:   }
 285: 
 286:   /**
 287:    * Returns the next model location that is visible in eiter north / south
 288:    * direction or east / west direction. This is used to determine the placement
 289:    * of the caret when navigating around the document with the arrow keys. This
 290:    * is a convenience method for {@link #getNextNorthSouthVisualPositionFrom}
 291:    * and {@link #getNextEastWestVisualPositionFrom}.
 292:    * 
 293:    * @param pos
 294:    *          the model position to start search from
 295:    * @param b
 296:    *          the bias for <code>pos</code>
 297:    * @param a
 298:    *          the allocated region for this view
 299:    * @param direction
 300:    *          the direction from the current position, can be one of the
 301:    *          following:
 302:    *          <ul>
 303:    *          <li>{@link SwingConstants#WEST}</li>
 304:    *          <li>{@link SwingConstants#EAST}</li>
 305:    *          <li>{@link SwingConstants#NORTH}</li>
 306:    *          <li>{@link SwingConstants#SOUTH}</li>
 307:    *          </ul>
 308:    * @param biasRet
 309:    *          the bias of the return value gets stored here
 310:    * @return the position inside the model that represents the next visual
 311:    *         location
 312:    * @throws BadLocationException
 313:    *           if <code>pos</code> is not a valid location inside the document
 314:    *           model
 315:    * @throws IllegalArgumentException
 316:    *           if <code>direction</code> is invalid
 317:    */
 318:   public int getNextVisualPositionFrom(int pos, Position.Bias b, Shape a,
 319:                                        int direction, Position.Bias[] biasRet)
 320:     throws BadLocationException
 321:   {
 322:     int retVal = -1;
 323:     switch (direction)
 324:       {
 325:       case SwingConstants.WEST:
 326:       case SwingConstants.EAST:
 327:         retVal = getNextEastWestVisualPositionFrom(pos, b, a, direction,
 328:                                                    biasRet);
 329:         break;
 330:       case SwingConstants.NORTH:
 331:       case SwingConstants.SOUTH:
 332:         retVal = getNextNorthSouthVisualPositionFrom(pos, b, a, direction,
 333:                                                      biasRet);
 334:         break;
 335:       default:
 336:         throw new IllegalArgumentException("Illegal value for direction.");
 337:       }
 338:     return retVal;
 339:   }
 340: 
 341:   /**
 342:    * Returns the index of the child view that represents the specified
 343:    * model location.
 344:    *
 345:    * @param pos the model location for which to determine the child view index
 346:    * @param b the bias to be applied to <code>pos</code>
 347:    *
 348:    * @return the index of the child view that represents the specified
 349:    *         model location
 350:    */
 351:   public int getViewIndex(int pos, Position.Bias b)
 352:   {
 353:     // FIXME: Handle bias somehow.
 354:     return getViewIndexAtPosition(pos);
 355:   }
 356: 
 357:   /**
 358:    * Returns <code>true</code> if the specified point lies before the
 359:    * given <code>Rectangle</code>, <code>false</code> otherwise.
 360:    *
 361:    * &quot;Before&quot; is typically defined as being to the left or above.
 362:    *
 363:    * @param x the X coordinate of the point
 364:    * @param y the Y coordinate of the point
 365:    * @param r the rectangle to test the point against
 366:    *
 367:    * @return <code>true</code> if the specified point lies before the
 368:    *         given <code>Rectangle</code>, <code>false</code> otherwise
 369:    */
 370:   protected abstract boolean isBefore(int x, int y, Rectangle r);
 371: 
 372:   /**
 373:    * Returns <code>true</code> if the specified point lies after the
 374:    * given <code>Rectangle</code>, <code>false</code> otherwise.
 375:    *
 376:    * &quot;After&quot; is typically defined as being to the right or below.
 377:    *
 378:    * @param x the X coordinate of the point
 379:    * @param y the Y coordinate of the point
 380:    * @param r the rectangle to test the point against
 381:    *
 382:    * @return <code>true</code> if the specified point lies after the
 383:    *         given <code>Rectangle</code>, <code>false</code> otherwise
 384:    */
 385:   protected abstract boolean isAfter(int x, int y, Rectangle r);
 386: 
 387:   /**
 388:    * Returns the child <code>View</code> at the specified location.
 389:    *
 390:    * @param x the X coordinate
 391:    * @param y the Y coordinate
 392:    * @param r the inner allocation of this <code>BoxView</code> on entry,
 393:    *        the allocation of the found child on exit
 394:    *
 395:    * @return the child <code>View</code> at the specified location
 396:    */
 397:   protected abstract View getViewAtPoint(int x, int y, Rectangle r);
 398: 
 399:   /**
 400:    * Computes the allocation for a child <code>View</code>. The parameter
 401:    * <code>a</code> stores the allocation of this <code>CompositeView</code>
 402:    * and is then adjusted to hold the allocation of the child view.
 403:    *
 404:    * @param index the index of the child <code>View</code>
 405:    * @param a the allocation of this <code>CompositeView</code> before the
 406:    *        call, the allocation of the child on exit
 407:    */
 408:   protected abstract void childAllocation(int index, Rectangle a);
 409: 
 410:   /**
 411:    * Returns the child <code>View</code> that contains the given model
 412:    * position. The given <code>Rectangle</code> gives the parent's allocation
 413:    * and is changed to the child's allocation on exit.
 414:    *
 415:    * @param pos the model position to query the child <code>View</code> for
 416:    * @param a the parent allocation on entry and the child allocation on exit
 417:    *
 418:    * @return the child view at the given model position
 419:    */
 420:   protected View getViewAtPosition(int pos, Rectangle a)
 421:   {
 422:     int i = getViewIndexAtPosition(pos);
 423:     View view = children[i];
 424:     childAllocation(i, a);
 425:     return view;
 426:   }
 427: 
 428:   /**
 429:    * Returns the index of the child <code>View</code> for the given model
 430:    * position.
 431:    *
 432:    * @param pos the model position for whicht the child <code>View</code> is
 433:    *        queried
 434:    *
 435:    * @return the index of the child <code>View</code> for the given model
 436:    *         position
 437:    */
 438:   protected int getViewIndexAtPosition(int pos)
 439:   {
 440:     int index = -1;
 441:     for (int i = 0; i < children.length; i++)
 442:       {
 443:         if (children[i].getStartOffset() <= pos
 444:             && children[i].getEndOffset() > pos)
 445:           {
 446:             index = i;
 447:             break;
 448:           }
 449:       }
 450:     return index;
 451:   }
 452: 
 453:   /**
 454:    * Returns the allocation that is given to this <code>CompositeView</code>
 455:    * minus this <code>CompositeView</code>'s insets.
 456:    *
 457:    * Also this translates from an immutable allocation to a mutable allocation
 458:    * that is typically reused and further narrowed, like in
 459:    * {@link #childAllocation}.
 460:    *
 461:    * @param a the allocation given to this <code>CompositeView</code>
 462:    *
 463:    * @return the allocation that is given to this <code>CompositeView</code>
 464:    *         minus this <code>CompositeView</code>'s insets or
 465:    *         <code>null</code> if a was <code>null</code>
 466:    */
 467:   protected Rectangle getInsideAllocation(Shape a)
 468:   {
 469:     if (a == null)
 470:       return null;
 471: 
 472:     Rectangle alloc = a.getBounds();
 473:     // Initialize the inside allocation rectangle. This is done inside
 474:     // a synchronized block in order to avoid multiple threads creating
 475:     // this instance simultanously.
 476:     Rectangle inside;
 477:     synchronized(this)
 478:       {
 479:         inside = insideAllocation;
 480:         if (inside == null)
 481:           {
 482:             inside = new Rectangle();
 483:             insideAllocation = inside;
 484:           }
 485:       }
 486:     inside.x = alloc.x + insets.left;
 487:     inside.y = alloc.y + insets.top;
 488:     inside.width = alloc.width - insets.left - insets.right;
 489:     inside.height = alloc.height - insets.top - insets.bottom;
 490:     return inside;
 491:   }
 492: 
 493:   /**
 494:    * Sets the insets defined by attributes in <code>attributes</code>. This
 495:    * queries the attribute keys {@link StyleConstants#SpaceAbove},
 496:    * {@link StyleConstants#SpaceBelow}, {@link StyleConstants#LeftIndent} and
 497:    * {@link StyleConstants#RightIndent} and calls {@link #setInsets} to
 498:    * actually set the insets on this <code>CompositeView</code>.
 499:    *
 500:    * @param attributes the attributes from which to query the insets
 501:    */
 502:   protected void setParagraphInsets(AttributeSet attributes)
 503:   {
 504:     Float l = (Float) attributes.getAttribute(StyleConstants.LeftIndent);
 505:     short left = 0;
 506:     if (l != null)
 507:       left = l.shortValue();
 508:     Float r = (Float) attributes.getAttribute(StyleConstants.RightIndent);
 509:     short right = 0;
 510:     if (r != null)
 511:       right = r.shortValue();
 512:     Float t = (Float) attributes.getAttribute(StyleConstants.SpaceAbove);
 513:     short top = 0;
 514:     if (t != null)
 515:       top = t.shortValue();
 516:     Float b = (Float) attributes.getAttribute(StyleConstants.SpaceBelow);
 517:     short bottom = 0;
 518:     if (b != null)
 519:       bottom = b.shortValue();
 520:     setInsets(top, left, bottom, right);
 521:   }
 522: 
 523:   /**
 524:    * Sets the insets of this <code>CompositeView</code>.
 525:    *
 526:    * @param top the top inset
 527:    * @param left the left inset
 528:    * @param bottom the bottom inset
 529:    * @param right the right inset
 530:    */
 531:   protected void setInsets(short top, short left, short bottom, short right)
 532:   {
 533:     insets.top = top;
 534:     insets.left = left;
 535:     insets.bottom = bottom;
 536:     insets.right = right;
 537:   }
 538: 
 539:   /**
 540:    * Returns the left inset of this <code>CompositeView</code>.
 541:    *
 542:    * @return the left inset of this <code>CompositeView</code>
 543:    */
 544:   protected short getLeftInset()
 545:   {
 546:     return (short) insets.left;
 547:   }
 548: 
 549:   /**
 550:    * Returns the right inset of this <code>CompositeView</code>.
 551:    *
 552:    * @return the right inset of this <code>CompositeView</code>
 553:    */
 554:   protected short getRightInset()
 555:   {
 556:     return (short) insets.right;
 557:   }
 558: 
 559:   /**
 560:    * Returns the top inset of this <code>CompositeView</code>.
 561:    *
 562:    * @return the top inset of this <code>CompositeView</code>
 563:    */
 564:   protected short getTopInset()
 565:   {
 566:     return (short) insets.top;
 567:   }
 568: 
 569:   /**
 570:    * Returns the bottom inset of this <code>CompositeView</code>.
 571:    *
 572:    * @return the bottom inset of this <code>CompositeView</code>
 573:    */
 574:   protected short getBottomInset()
 575:   {
 576:     return (short) insets.bottom;
 577:   }
 578: 
 579:   /**
 580:    * Returns the next model location that is visible in north or south
 581:    * direction.
 582:    * This is used to determine the
 583:    * placement of the caret when navigating around the document with
 584:    * the arrow keys.
 585:    *
 586:    * @param pos the model position to start search from
 587:    * @param b the bias for <code>pos</code>
 588:    * @param a the allocated region for this view
 589:    * @param direction the direction from the current position, can be one of
 590:    *        the following:
 591:    *        <ul>
 592:    *        <li>{@link SwingConstants#NORTH}</li>
 593:    *        <li>{@link SwingConstants#SOUTH}</li>
 594:    *        </ul>
 595:    * @param biasRet the bias of the return value gets stored here
 596:    *
 597:    * @return the position inside the model that represents the next visual
 598:    *         location
 599:    *
 600:    * @throws BadLocationException if <code>pos</code> is not a valid location
 601:    *         inside the document model
 602:    * @throws IllegalArgumentException if <code>direction</code> is invalid
 603:    */
 604:   protected int getNextNorthSouthVisualPositionFrom(int pos, Position.Bias b,
 605:                                                     Shape a, int direction,
 606:                                                     Position.Bias[] biasRet)
 607:     throws BadLocationException
 608:   {
 609:     // FIXME: Implement this correctly.
 610:     return pos;
 611:   }
 612: 
 613:   /**
 614:    * Returns the next model location that is visible in east or west
 615:    * direction.
 616:    * This is used to determine the
 617:    * placement of the caret when navigating around the document with
 618:    * the arrow keys.
 619:    *
 620:    * @param pos the model position to start search from
 621:    * @param b the bias for <code>pos</code>
 622:    * @param a the allocated region for this view
 623:    * @param direction the direction from the current position, can be one of
 624:    *        the following:
 625:    *        <ul>
 626:    *        <li>{@link SwingConstants#EAST}</li>
 627:    *        <li>{@link SwingConstants#WEST}</li>
 628:    *        </ul>
 629:    * @param biasRet the bias of the return value gets stored here
 630:    *
 631:    * @return the position inside the model that represents the next visual
 632:    *         location
 633:    *
 634:    * @throws BadLocationException if <code>pos</code> is not a valid location
 635:    *         inside the document model
 636:    * @throws IllegalArgumentException if <code>direction</code> is invalid
 637:    */
 638:   protected int getNextEastWestVisualPositionFrom(int pos, Position.Bias b,
 639:                                                   Shape a, int direction,
 640:                                                   Position.Bias[] biasRet)
 641:     throws BadLocationException
 642:   {
 643:     // FIXME: Implement this correctly.
 644:     return pos;
 645:   }
 646: 
 647:   /**
 648:    * Determines if the next view in horinzontal direction is located to
 649:    * the east or west of the view at position <code>pos</code>. Usually
 650:    * the <code>View</code>s are laid out from the east to the west, so
 651:    * we unconditionally return <code>false</code> here. Subclasses that
 652:    * support bidirectional text may wish to override this method.
 653:    *
 654:    * @param pos the position in the document
 655:    * @param bias the bias to be applied to <code>pos</code>
 656:    *
 657:    * @return <code>true</code> if the next <code>View</code> is located
 658:    *         to the EAST, <code>false</code> otherwise
 659:    */
 660:   protected boolean flipEastAndWestAtEnds(int pos, Position.Bias bias)
 661:   {
 662:     return false;
 663:   }
 664: }