Showing the changes to java/pkg/java/awt/BorderLayout.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,887 @@ | ||
| 1 | +/* | |
| 2 | + * Copyright (c) 1995, 2006, Oracle and/or its affiliates. All rights reserved. | |
| 3 | + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| 4 | + * | |
| 5 | + * This code is free software; you can redistribute it and/or modify it | |
| 6 | + * under the terms of the GNU General Public License version 2 only, as | |
| 7 | + * published by the Free Software Foundation. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle in the LICENSE file that accompanied this code. | |
| 10 | + * | |
| 11 | + * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 | + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 | + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 | + * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 | + * accompanied this code). | |
| 16 | + * | |
| 17 | + * You should have received a copy of the GNU General Public License version | |
| 18 | + * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 | + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | + * | |
| 21 | + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +package java.awt; | |
| 27 | + | |
| 28 | +import java.util.Hashtable; | |
| 29 | + | |
| 30 | +/** | |
| 31 | + * A border layout lays out a container, arranging and resizing | |
| 32 | + * its components to fit in five regions: | |
| 33 | + * north, south, east, west, and center. | |
| 34 | + * Each region may contain no more than one component, and | |
| 35 | + * is identified by a corresponding constant: | |
| 36 | + * <code>NORTH</code>, <code>SOUTH</code>, <code>EAST</code>, | |
| 37 | + * <code>WEST</code>, and <code>CENTER</code>. When adding a | |
| 38 | + * component to a container with a border layout, use one of these | |
| 39 | + * five constants, for example: | |
| 40 | + * <pre> | |
| 41 | + * Panel p = new Panel(); | |
| 42 | + * p.setLayout(new BorderLayout()); | |
| 43 | + * p.add(new Button("Okay"), BorderLayout.SOUTH); | |
| 44 | + * </pre> | |
| 45 | + * As a convenience, <code>BorderLayout</code> interprets the | |
| 46 | + * absence of a string specification the same as the constant | |
| 47 | + * <code>CENTER</code>: | |
| 48 | + * <pre> | |
| 49 | + * Panel p2 = new Panel(); | |
| 50 | + * p2.setLayout(new BorderLayout()); | |
| 51 | + * p2.add(new TextArea()); // Same as p.add(new TextArea(), BorderLayout.CENTER); | |
| 52 | + * </pre> | |
| 53 | + * <p> | |
| 54 | + * In addition, <code>BorderLayout</code> supports the relative | |
| 55 | + * positioning constants, <code>PAGE_START</code>, <code>PAGE_END</code>, | |
| 56 | + * <code>LINE_START</code>, and <code>LINE_END</code>. | |
| 57 | + * In a container whose <code>ComponentOrientation</code> is set to | |
| 58 | + * <code>ComponentOrientation.LEFT_TO_RIGHT</code>, these constants map to | |
| 59 | + * <code>NORTH</code>, <code>SOUTH</code>, <code>WEST</code>, and | |
| 60 | + * <code>EAST</code>, respectively. | |
| 61 | + * <p> | |
| 62 | + * For compatibility with previous releases, <code>BorderLayout</code> | |
| 63 | + * also includes the relative positioning constants <code>BEFORE_FIRST_LINE</code>, | |
| 64 | + * <code>AFTER_LAST_LINE</code>, <code>BEFORE_LINE_BEGINS</code> and | |
| 65 | + * <code>AFTER_LINE_ENDS</code>. These are equivalent to | |
| 66 | + * <code>PAGE_START</code>, <code>PAGE_END</code>, <code>LINE_START</code> | |
| 67 | + * and <code>LINE_END</code> respectively. For | |
| 68 | + * consistency with the relative positioning constants used by other | |
| 69 | + * components, the latter constants are preferred. | |
| 70 | + * <p> | |
| 71 | + * Mixing both absolute and relative positioning constants can lead to | |
| 72 | + * unpredicable results. If | |
| 73 | + * you use both types, the relative constants will take precedence. | |
| 74 | + * For example, if you add components using both the <code>NORTH</code> | |
| 75 | + * and <code>PAGE_START</code> constants in a container whose | |
| 76 | + * orientation is <code>LEFT_TO_RIGHT</code>, only the | |
| 77 | + * <code>PAGE_START</code> will be layed out. | |
| 78 | + * <p> | |
| 79 | + * NOTE: Currently (in the Java 2 platform v1.2), | |
| 80 | + * <code>BorderLayout</code> does not support vertical | |
| 81 | + * orientations. The <code>isVertical</code> setting on the container's | |
| 82 | + * <code>ComponentOrientation</code> is not respected. | |
| 83 | + * <p> | |
| 84 | + * The components are laid out according to their | |
| 85 | + * preferred sizes and the constraints of the container's size. | |
| 86 | + * The <code>NORTH</code> and <code>SOUTH</code> components may | |
| 87 | + * be stretched horizontally; the <code>EAST</code> and | |
| 88 | + * <code>WEST</code> components may be stretched vertically; | |
| 89 | + * the <code>CENTER</code> component may stretch both horizontally | |
| 90 | + * and vertically to fill any space left over. | |
| 91 | + * <p> | |
| 92 | + * Here is an example of five buttons in an applet laid out using | |
| 93 | + * the <code>BorderLayout</code> layout manager: | |
| 94 | + * <p> | |
| 95 | + * <img src="doc-files/BorderLayout-1.gif" | |
| 96 | + * alt="Diagram of an applet demonstrating BorderLayout. | |
| 97 | + * Each section of the BorderLayout contains a Button corresponding to its position in the layout, one of: | |
| 98 | + * North, West, Center, East, or South." | |
| 99 | + * ALIGN=center HSPACE=10 VSPACE=7> | |
| 100 | + * <p> | |
| 101 | + * The code for this applet is as follows: | |
| 102 | + * <p> | |
| 103 | + * <hr><blockquote><pre> | |
| 104 | + * import java.awt.*; | |
| 105 | + * import java.applet.Applet; | |
| 106 | + * | |
| 107 | + * public class buttonDir extends Applet { | |
| 108 | + * public void init() { | |
| 109 | + * setLayout(new BorderLayout()); | |
| 110 | + * add(new Button("North"), BorderLayout.NORTH); | |
| 111 | + * add(new Button("South"), BorderLayout.SOUTH); | |
| 112 | + * add(new Button("East"), BorderLayout.EAST); | |
| 113 | + * add(new Button("West"), BorderLayout.WEST); | |
| 114 | + * add(new Button("Center"), BorderLayout.CENTER); | |
| 115 | + * } | |
| 116 | + * } | |
| 117 | + * </pre></blockquote><hr> | |
| 118 | + * <p> | |
| 119 | + * @author Arthur van Hoff | |
| 120 | + * @see java.awt.Container#add(String, Component) | |
| 121 | + * @see java.awt.ComponentOrientation | |
| 122 | + * @since JDK1.0 | |
| 123 | + */ | |
| 124 | +public class BorderLayout implements LayoutManager2, | |
| 125 | + java.io.Serializable { | |
| 126 | + /** | |
| 127 | + * Constructs a border layout with the horizontal gaps | |
| 128 | + * between components. | |
| 129 | + * The horizontal gap is specified by <code>hgap</code>. | |
| 130 | + * | |
| 131 | + * @see #getHgap() | |
| 132 | + * @see #setHgap(int) | |
| 133 | + * | |
| 134 | + * @serial | |
| 135 | + */ | |
| 136 | + int hgap; | |
| 137 | + | |
| 138 | + /** | |
| 139 | + * Constructs a border layout with the vertical gaps | |
| 140 | + * between components. | |
| 141 | + * The vertical gap is specified by <code>vgap</code>. | |
| 142 | + * | |
| 143 | + * @see #getVgap() | |
| 144 | + * @see #setVgap(int) | |
| 145 | + * @serial | |
| 146 | + */ | |
| 147 | + int vgap; | |
| 148 | + | |
| 149 | + /** | |
| 150 | + * Constant to specify components location to be the | |
| 151 | + * north portion of the border layout. | |
| 152 | + * @serial | |
| 153 | + * @see #getChild(String, boolean) | |
| 154 | + * @see #addLayoutComponent | |
| 155 | + * @see #getLayoutAlignmentX | |
| 156 | + * @see #getLayoutAlignmentY | |
| 157 | + * @see #removeLayoutComponent | |
| 158 | + */ | |
| 159 | + Component north; | |
| 160 | + /** | |
| 161 | + * Constant to specify components location to be the | |
| 162 | + * west portion of the border layout. | |
| 163 | + * @serial | |
| 164 | + * @see #getChild(String, boolean) | |
| 165 | + * @see #addLayoutComponent | |
| 166 | + * @see #getLayoutAlignmentX | |
| 167 | + * @see #getLayoutAlignmentY | |
| 168 | + * @see #removeLayoutComponent | |
| 169 | + */ | |
| 170 | + Component west; | |
| 171 | + /** | |
| 172 | + * Constant to specify components location to be the | |
| 173 | + * east portion of the border layout. | |
| 174 | + * @serial | |
| 175 | + * @see #getChild(String, boolean) | |
| 176 | + * @see #addLayoutComponent | |
| 177 | + * @see #getLayoutAlignmentX | |
| 178 | + * @see #getLayoutAlignmentY | |
| 179 | + * @see #removeLayoutComponent | |
| 180 | + */ | |
| 181 | + Component east; | |
| 182 | + /** | |
| 183 | + * Constant to specify components location to be the | |
| 184 | + * south portion of the border layout. | |
| 185 | + * @serial | |
| 186 | + * @see #getChild(String, boolean) | |
| 187 | + * @see #addLayoutComponent | |
| 188 | + * @see #getLayoutAlignmentX | |
| 189 | + * @see #getLayoutAlignmentY | |
| 190 | + * @see #removeLayoutComponent | |
| 191 | + */ | |
| 192 | + Component south; | |
| 193 | + /** | |
| 194 | + * Constant to specify components location to be the | |
| 195 | + * center portion of the border layout. | |
| 196 | + * @serial | |
| 197 | + * @see #getChild(String, boolean) | |
| 198 | + * @see #addLayoutComponent | |
| 199 | + * @see #getLayoutAlignmentX | |
| 200 | + * @see #getLayoutAlignmentY | |
| 201 | + * @see #removeLayoutComponent | |
| 202 | + */ | |
| 203 | + Component center; | |
| 204 | + | |
| 205 | + /** | |
| 206 | + * | |
| 207 | + * A relative positioning constant, that can be used instead of | |
| 208 | + * north, south, east, west or center. | |
| 209 | + * mixing the two types of constants can lead to unpredicable results. If | |
| 210 | + * you use both types, the relative constants will take precedence. | |
| 211 | + * For example, if you add components using both the <code>NORTH</code> | |
| 212 | + * and <code>BEFORE_FIRST_LINE</code> constants in a container whose | |
| 213 | + * orientation is <code>LEFT_TO_RIGHT</code>, only the | |
| 214 | + * <code>BEFORE_FIRST_LINE</code> will be layed out. | |
| 215 | + * This will be the same for lastLine, firstItem, lastItem. | |
| 216 | + * @serial | |
| 217 | + */ | |
| 218 | + Component firstLine; | |
| 219 | + /** | |
| 220 | + * A relative positioning constant, that can be used instead of | |
| 221 | + * north, south, east, west or center. | |
| 222 | + * Please read Description for firstLine. | |
| 223 | + * @serial | |
| 224 | + */ | |
| 225 | + Component lastLine; | |
| 226 | + /** | |
| 227 | + * A relative positioning constant, that can be used instead of | |
| 228 | + * north, south, east, west or center. | |
| 229 | + * Please read Description for firstLine. | |
| 230 | + * @serial | |
| 231 | + */ | |
| 232 | + Component firstItem; | |
| 233 | + /** | |
| 234 | + * A relative positioning constant, that can be used instead of | |
| 235 | + * north, south, east, west or center. | |
| 236 | + * Please read Description for firstLine. | |
| 237 | + * @serial | |
| 238 | + */ | |
| 239 | + Component lastItem; | |
| 240 | + | |
| 241 | + /** | |
| 242 | + * The north layout constraint (top of container). | |
| 243 | + */ | |
| 244 | + public static final String NORTH = "North"; | |
| 245 | + | |
| 246 | + /** | |
| 247 | + * The south layout constraint (bottom of container). | |
| 248 | + */ | |
| 249 | + public static final String SOUTH = "South"; | |
| 250 | + | |
| 251 | + /** | |
| 252 | + * The east layout constraint (right side of container). | |
| 253 | + */ | |
| 254 | + public static final String EAST = "East"; | |
| 255 | + | |
| 256 | + /** | |
| 257 | + * The west layout constraint (left side of container). | |
| 258 | + */ | |
| 259 | + public static final String WEST = "West"; | |
| 260 | + | |
| 261 | + /** | |
| 262 | + * The center layout constraint (middle of container). | |
| 263 | + */ | |
| 264 | + public static final String CENTER = "Center"; | |
| 265 | + | |
| 266 | + /** | |
| 267 | + * Synonym for PAGE_START. Exists for compatibility with previous | |
| 268 | + * versions. PAGE_START is preferred. | |
| 269 | + * | |
| 270 | + * @see #PAGE_START | |
| 271 | + * @since 1.2 | |
| 272 | + */ | |
| 273 | + public static final String BEFORE_FIRST_LINE = "First"; | |
| 274 | + | |
| 275 | + /** | |
| 276 | + * Synonym for PAGE_END. Exists for compatibility with previous | |
| 277 | + * versions. PAGE_END is preferred. | |
| 278 | + * | |
| 279 | + * @see #PAGE_END | |
| 280 | + * @since 1.2 | |
| 281 | + */ | |
| 282 | + public static final String AFTER_LAST_LINE = "Last"; | |
| 283 | + | |
| 284 | + /** | |
| 285 | + * Synonym for LINE_START. Exists for compatibility with previous | |
| 286 | + * versions. LINE_START is preferred. | |
| 287 | + * | |
| 288 | + * @see #LINE_START | |
| 289 | + * @since 1.2 | |
| 290 | + */ | |
| 291 | + public static final String BEFORE_LINE_BEGINS = "Before"; | |
| 292 | + | |
| 293 | + /** | |
| 294 | + * Synonym for LINE_END. Exists for compatibility with previous | |
| 295 | + * versions. LINE_END is preferred. | |
| 296 | + * | |
| 297 | + * @see #LINE_END | |
| 298 | + * @since 1.2 | |
| 299 | + */ | |
| 300 | + public static final String AFTER_LINE_ENDS = "After"; | |
| 301 | + | |
| 302 | + /** | |
| 303 | + * The component comes before the first line of the layout's content. | |
| 304 | + * For Western, left-to-right and top-to-bottom orientations, this is | |
| 305 | + * equivalent to NORTH. | |
| 306 | + * | |
| 307 | + * @see java.awt.Component#getComponentOrientation | |
| 308 | + * @since 1.4 | |
| 309 | + */ | |
| 310 | + public static final String PAGE_START = BEFORE_FIRST_LINE; | |
| 311 | + | |
| 312 | + /** | |
| 313 | + * The component comes after the last line of the layout's content. | |
| 314 | + * For Western, left-to-right and top-to-bottom orientations, this is | |
| 315 | + * equivalent to SOUTH. | |
| 316 | + * | |
| 317 | + * @see java.awt.Component#getComponentOrientation | |
| 318 | + * @since 1.4 | |
| 319 | + */ | |
| 320 | + public static final String PAGE_END = AFTER_LAST_LINE; | |
| 321 | + | |
| 322 | + /** | |
| 323 | + * The component goes at the beginning of the line direction for the | |
| 324 | + * layout. For Western, left-to-right and top-to-bottom orientations, | |
| 325 | + * this is equivalent to WEST. | |
| 326 | + * | |
| 327 | + * @see java.awt.Component#getComponentOrientation | |
| 328 | + * @since 1.4 | |
| 329 | + */ | |
| 330 | + public static final String LINE_START = BEFORE_LINE_BEGINS; | |
| 331 | + | |
| 332 | + /** | |
| 333 | + * The component goes at the end of the line direction for the | |
| 334 | + * layout. For Western, left-to-right and top-to-bottom orientations, | |
| 335 | + * this is equivalent to EAST. | |
| 336 | + * | |
| 337 | + * @see java.awt.Component#getComponentOrientation | |
| 338 | + * @since 1.4 | |
| 339 | + */ | |
| 340 | + public static final String LINE_END = AFTER_LINE_ENDS; | |
| 341 | + | |
| 342 | + /* | |
| 343 | + * JDK 1.1 serialVersionUID | |
| 344 | + */ | |
| 345 | + private static final long serialVersionUID = -8658291919501921765L; | |
| 346 | + | |
| 347 | + /** | |
| 348 | + * Constructs a new border layout with | |
| 349 | + * no gaps between components. | |
| 350 | + */ | |
| 351 | + public BorderLayout() { | |
| 352 | + this(0, 0); | |
| 353 | + } | |
| 354 | + | |
| 355 | + /** | |
| 356 | + * Constructs a border layout with the specified gaps | |
| 357 | + * between components. | |
| 358 | + * The horizontal gap is specified by <code>hgap</code> | |
| 359 | + * and the vertical gap is specified by <code>vgap</code>. | |
| 360 | + * @param hgap the horizontal gap. | |
| 361 | + * @param vgap the vertical gap. | |
| 362 | + */ | |
| 363 | + public BorderLayout(int hgap, int vgap) { | |
| 364 | + this.hgap = hgap; | |
| 365 | + this.vgap = vgap; | |
| 366 | + } | |
| 367 | + | |
| 368 | + /** | |
| 369 | + * Returns the horizontal gap between components. | |
| 370 | + * @since JDK1.1 | |
| 371 | + */ | |
| 372 | + public int getHgap() { | |
| 373 | + return hgap; | |
| 374 | + } | |
| 375 | + | |
| 376 | + /** | |
| 377 | + * Sets the horizontal gap between components. | |
| 378 | + * @param hgap the horizontal gap between components | |
| 379 | + * @since JDK1.1 | |
| 380 | + */ | |
| 381 | + public void setHgap(int hgap) { | |
| 382 | + this.hgap = hgap; | |
| 383 | + } | |
| 384 | + | |
| 385 | + /** | |
| 386 | + * Returns the vertical gap between components. | |
| 387 | + * @since JDK1.1 | |
| 388 | + */ | |
| 389 | + public int getVgap() { | |
| 390 | + return vgap; | |
| 391 | + } | |
| 392 | + | |
| 393 | + /** | |
| 394 | + * Sets the vertical gap between components. | |
| 395 | + * @param vgap the vertical gap between components | |
| 396 | + * @since JDK1.1 | |
| 397 | + */ | |
| 398 | + public void setVgap(int vgap) { | |
| 399 | + this.vgap = vgap; | |
| 400 | + } | |
| 401 | + | |
| 402 | + /** | |
| 403 | + * Adds the specified component to the layout, using the specified | |
| 404 | + * constraint object. For border layouts, the constraint must be | |
| 405 | + * one of the following constants: <code>NORTH</code>, | |
| 406 | + * <code>SOUTH</code>, <code>EAST</code>, | |
| 407 | + * <code>WEST</code>, or <code>CENTER</code>. | |
| 408 | + * <p> | |
| 409 | + * Most applications do not call this method directly. This method | |
| 410 | + * is called when a component is added to a container using the | |
| 411 | + * <code>Container.add</code> method with the same argument types. | |
| 412 | + * @param comp the component to be added. | |
| 413 | + * @param constraints an object that specifies how and where | |
| 414 | + * the component is added to the layout. | |
| 415 | + * @see java.awt.Container#add(java.awt.Component, java.lang.Object) | |
| 416 | + * @exception IllegalArgumentException if the constraint object is not | |
| 417 | + * a string, or if it not one of the five specified | |
| 418 | + * constants. | |
| 419 | + * @since JDK1.1 | |
| 420 | + */ | |
| 421 | + public void addLayoutComponent(Component comp, Object constraints) { | |
| 422 | + synchronized (comp.getTreeLock()) { | |
| 423 | + if ((constraints == null) || (constraints instanceof String)) { | |
| 424 | + addLayoutComponent((String)constraints, comp); | |
| 425 | + } else { | |
| 426 | + throw new IllegalArgumentException("cannot add to layout: constraint must be a string (or null)"); | |
| 427 | + } | |
| 428 | + } | |
| 429 | + } | |
| 430 | + | |
| 431 | + /** | |
| 432 | + * @deprecated replaced by <code>addLayoutComponent(Component, Object)</code>. | |
| 433 | + */ | |
| 434 | + @Deprecated | |
| 435 | + public void addLayoutComponent(String name, Component comp) { | |
| 436 | + synchronized (comp.getTreeLock()) { | |
| 437 | + /* Special case: treat null the same as "Center". */ | |
| 438 | + if (name == null) { | |
| 439 | + name = "Center"; | |
| 440 | + } | |
| 441 | + | |
| 442 | + /* Assign the component to one of the known regions of the layout. | |
| 443 | + */ | |
| 444 | + if ("Center".equals(name)) { | |
| 445 | + center = comp; | |
| 446 | + } else if ("North".equals(name)) { | |
| 447 | + north = comp; | |
| 448 | + } else if ("South".equals(name)) { | |
| 449 | + south = comp; | |
| 450 | + } else if ("East".equals(name)) { | |
| 451 | + east = comp; | |
| 452 | + } else if ("West".equals(name)) { | |
| 453 | + west = comp; | |
| 454 | + } else if (BEFORE_FIRST_LINE.equals(name)) { | |
| 455 | + firstLine = comp; | |
| 456 | + } else if (AFTER_LAST_LINE.equals(name)) { | |
| 457 | + lastLine = comp; | |
| 458 | + } else if (BEFORE_LINE_BEGINS.equals(name)) { | |
| 459 | + firstItem = comp; | |
| 460 | + } else if (AFTER_LINE_ENDS.equals(name)) { | |
| 461 | + lastItem = comp; | |
| 462 | + } else { | |
| 463 | + throw new IllegalArgumentException("cannot add to layout: unknown constraint: " + name); | |
| 464 | + } | |
| 465 | + } | |
| 466 | + } | |
| 467 | + | |
| 468 | + /** | |
| 469 | + * Removes the specified component from this border layout. This | |
| 470 | + * method is called when a container calls its <code>remove</code> or | |
| 471 | + * <code>removeAll</code> methods. Most applications do not call this | |
| 472 | + * method directly. | |
| 473 | + * @param comp the component to be removed. | |
| 474 | + * @see java.awt.Container#remove(java.awt.Component) | |
| 475 | + * @see java.awt.Container#removeAll() | |
| 476 | + */ | |
| 477 | + public void removeLayoutComponent(Component comp) { | |
| 478 | + synchronized (comp.getTreeLock()) { | |
| 479 | + if (comp == center) { | |
| 480 | + center = null; | |
| 481 | + } else if (comp == north) { | |
| 482 | + north = null; | |
| 483 | + } else if (comp == south) { | |
| 484 | + south = null; | |
| 485 | + } else if (comp == east) { | |
| 486 | + east = null; | |
| 487 | + } else if (comp == west) { | |
| 488 | + west = null; | |
| 489 | + } | |
| 490 | + if (comp == firstLine) { | |
| 491 | + firstLine = null; | |
| 492 | + } else if (comp == lastLine) { | |
| 493 | + lastLine = null; | |
| 494 | + } else if (comp == firstItem) { | |
| 495 | + firstItem = null; | |
| 496 | + } else if (comp == lastItem) { | |
| 497 | + lastItem = null; | |
| 498 | + } | |
| 499 | + } | |
| 500 | + } | |
| 501 | + | |
| 502 | + /** | |
| 503 | + * Gets the component that was added using the given constraint | |
| 504 | + * | |
| 505 | + * @param constraints the desired constraint, one of <code>CENTER</code>, | |
| 506 | + * <code>NORTH</code>, <code>SOUTH</code>, | |
| 507 | + * <code>WEST</code>, <code>EAST</code>, | |
| 508 | + * <code>PAGE_START</code>, <code>PAGE_END</code>, | |
| 509 | + * <code>LINE_START</code>, <code>LINE_END</code> | |
| 510 | + * @return the component at the given location, or <code>null</code> if | |
| 511 | + * the location is empty | |
| 512 | + * @exception IllegalArgumentException if the constraint object is | |
| 513 | + * not one of the nine specified constants | |
| 514 | + * @see #addLayoutComponent(java.awt.Component, java.lang.Object) | |
| 515 | + * @since 1.5 | |
| 516 | + */ | |
| 517 | + public Component getLayoutComponent(Object constraints) { | |
| 518 | + if (CENTER.equals(constraints)) { | |
| 519 | + return center; | |
| 520 | + } else if (NORTH.equals(constraints)) { | |
| 521 | + return north; | |
| 522 | + } else if (SOUTH.equals(constraints)) { | |
| 523 | + return south; | |
| 524 | + } else if (WEST.equals(constraints)) { | |
| 525 | + return west; | |
| 526 | + } else if (EAST.equals(constraints)) { | |
| 527 | + return east; | |
| 528 | + } else if (PAGE_START.equals(constraints)) { | |
| 529 | + return firstLine; | |
| 530 | + } else if (PAGE_END.equals(constraints)) { | |
| 531 | + return lastLine; | |
| 532 | + } else if (LINE_START.equals(constraints)) { | |
| 533 | + return firstItem; | |
| 534 | + } else if (LINE_END.equals(constraints)) { | |
| 535 | + return lastItem; | |
| 536 | + } else { | |
| 537 | + throw new IllegalArgumentException("cannot get component: unknown constraint: " + constraints); | |
| 538 | + } | |
| 539 | + } | |
| 540 | + | |
| 541 | + | |
| 542 | + /** | |
| 543 | + * Returns the component that corresponds to the given constraint location | |
| 544 | + * based on the target <code>Container</code>'s component orientation. | |
| 545 | + * Components added with the relative constraints <code>PAGE_START</code>, | |
| 546 | + * <code>PAGE_END</code>, <code>LINE_START</code>, and <code>LINE_END</code> | |
| 547 | + * take precedence over components added with the explicit constraints | |
| 548 | + * <code>NORTH</code>, <code>SOUTH</code>, <code>WEST</code>, and <code>EAST</code>. | |
| 549 | + * The <code>Container</code>'s component orientation is used to determine the location of components | |
| 550 | + * added with <code>LINE_START</code> and <code>LINE_END</code>. | |
| 551 | + * | |
| 552 | + * @param constraints the desired absolute position, one of <code>CENTER</code>, | |
| 553 | + * <code>NORTH</code>, <code>SOUTH</code>, | |
| 554 | + * <code>EAST</code>, <code>WEST</code> | |
| 555 | + * @param target the {@code Container} used to obtain | |
| 556 | + * the constraint location based on the target | |
| 557 | + * {@code Container}'s component orientation. | |
| 558 | + * @return the component at the given location, or <code>null</code> if | |
| 559 | + * the location is empty | |
| 560 | + * @exception IllegalArgumentException if the constraint object is | |
| 561 | + * not one of the five specified constants | |
| 562 | + * @exception NullPointerException if the target parameter is null | |
| 563 | + * @see #addLayoutComponent(java.awt.Component, java.lang.Object) | |
| 564 | + * @since 1.5 | |
| 565 | + */ | |
| 566 | + public Component getLayoutComponent(Container target, Object constraints) { | |
| 567 | + boolean ltr = target.getComponentOrientation().isLeftToRight(); | |
| 568 | + Component result = null; | |
| 569 | + | |
| 570 | + if (NORTH.equals(constraints)) { | |
| 571 | + result = (firstLine != null) ? firstLine : north; | |
| 572 | + } else if (SOUTH.equals(constraints)) { | |
| 573 | + result = (lastLine != null) ? lastLine : south; | |
| 574 | + } else if (WEST.equals(constraints)) { | |
| 575 | + result = ltr ? firstItem : lastItem; | |
| 576 | + if (result == null) { | |
| 577 | + result = west; | |
| 578 | + } | |
| 579 | + } else if (EAST.equals(constraints)) { | |
| 580 | + result = ltr ? lastItem : firstItem; | |
| 581 | + if (result == null) { | |
| 582 | + result = east; | |
| 583 | + } | |
| 584 | + } else if (CENTER.equals(constraints)) { | |
| 585 | + result = center; | |
| 586 | + } else { | |
| 587 | + throw new IllegalArgumentException("cannot get component: invalid constraint: " + constraints); | |
| 588 | + } | |
| 589 | + | |
| 590 | + return result; | |
| 591 | + } | |
| 592 | + | |
| 593 | + | |
| 594 | + /** | |
| 595 | + * Gets the constraints for the specified component | |
| 596 | + * | |
| 597 | + * @param comp the component to be queried | |
| 598 | + * @return the constraint for the specified component, | |
| 599 | + * or null if component is null or is not present | |
| 600 | + * in this layout | |
| 601 | + * @see #addLayoutComponent(java.awt.Component, java.lang.Object) | |
| 602 | + * @since 1.5 | |
| 603 | + */ | |
| 604 | + public Object getConstraints(Component comp) { | |
| 605 | + //fix for 6242148 : API method java.awt.BorderLayout.getConstraints(null) should return null | |
| 606 | + if (comp == null){ | |
| 607 | + return null; | |
| 608 | + } | |
| 609 | + if (comp == center) { | |
| 610 | + return CENTER; | |
| 611 | + } else if (comp == north) { | |
| 612 | + return NORTH; | |
| 613 | + } else if (comp == south) { | |
| 614 | + return SOUTH; | |
| 615 | + } else if (comp == west) { | |
| 616 | + return WEST; | |
| 617 | + } else if (comp == east) { | |
| 618 | + return EAST; | |
| 619 | + } else if (comp == firstLine) { | |
| 620 | + return PAGE_START; | |
| 621 | + } else if (comp == lastLine) { | |
| 622 | + return PAGE_END; | |
| 623 | + } else if (comp == firstItem) { | |
| 624 | + return LINE_START; | |
| 625 | + } else if (comp == lastItem) { | |
| 626 | + return LINE_END; | |
| 627 | + } | |
| 628 | + return null; | |
| 629 | + } | |
| 630 | + | |
| 631 | + /** | |
| 632 | + * Determines the minimum size of the <code>target</code> container | |
| 633 | + * using this layout manager. | |
| 634 | + * <p> | |
| 635 | + * This method is called when a container calls its | |
| 636 | + * <code>getMinimumSize</code> method. Most applications do not call | |
| 637 | + * this method directly. | |
| 638 | + * @param target the container in which to do the layout. | |
| 639 | + * @return the minimum dimensions needed to lay out the subcomponents | |
| 640 | + * of the specified container. | |
| 641 | + * @see java.awt.Container | |
| 642 | + * @see java.awt.BorderLayout#preferredLayoutSize | |
| 643 | + * @see java.awt.Container#getMinimumSize() | |
| 644 | + */ | |
| 645 | + public Dimension minimumLayoutSize(Container target) { | |
| 646 | + synchronized (target.getTreeLock()) { | |
| 647 | + Dimension dim = new Dimension(0, 0); | |
| 648 | + | |
| 649 | + boolean ltr = target.getComponentOrientation().isLeftToRight(); | |
| 650 | + Component c = null; | |
| 651 | + | |
| 652 | + if ((c=getChild(EAST,ltr)) != null) { | |
| 653 | + Dimension d = c.getMinimumSize(); | |
| 654 | + dim.width += d.width + hgap; | |
| 655 | + dim.height = Math.max(d.height, dim.height); | |
| 656 | + } | |
| 657 | + if ((c=getChild(WEST,ltr)) != null) { | |
| 658 | + Dimension d = c.getMinimumSize(); | |
| 659 | + dim.width += d.width + hgap; | |
| 660 | + dim.height = Math.max(d.height, dim.height); | |
| 661 | + } | |
| 662 | + if ((c=getChild(CENTER,ltr)) != null) { | |
| 663 | + Dimension d = c.getMinimumSize(); | |
| 664 | + dim.width += d.width; | |
| 665 | + dim.height = Math.max(d.height, dim.height); | |
| 666 | + } | |
| 667 | + if ((c=getChild(NORTH,ltr)) != null) { | |
| 668 | + Dimension d = c.getMinimumSize(); | |
| 669 | + dim.width = Math.max(d.width, dim.width); | |
| 670 | + dim.height += d.height + vgap; | |
| 671 | + } | |
| 672 | + if ((c=getChild(SOUTH,ltr)) != null) { | |
| 673 | + Dimension d = c.getMinimumSize(); | |
| 674 | + dim.width = Math.max(d.width, dim.width); | |
| 675 | + dim.height += d.height + vgap; | |
| 676 | + } | |
| 677 | + | |
| 678 | + Insets insets = target.getInsets(); | |
| 679 | + dim.width += insets.left + insets.right; | |
| 680 | + dim.height += insets.top + insets.bottom; | |
| 681 | + | |
| 682 | + return dim; | |
| 683 | + } | |
| 684 | + } | |
| 685 | + | |
| 686 | + /** | |
| 687 | + * Determines the preferred size of the <code>target</code> | |
| 688 | + * container using this layout manager, based on the components | |
| 689 | + * in the container. | |
| 690 | + * <p> | |
| 691 | + * Most applications do not call this method directly. This method | |
| 692 | + * is called when a container calls its <code>getPreferredSize</code> | |
| 693 | + * method. | |
| 694 | + * @param target the container in which to do the layout. | |
| 695 | + * @return the preferred dimensions to lay out the subcomponents | |
| 696 | + * of the specified container. | |
| 697 | + * @see java.awt.Container | |
| 698 | + * @see java.awt.BorderLayout#minimumLayoutSize | |
| 699 | + * @see java.awt.Container#getPreferredSize() | |
| 700 | + */ | |
| 701 | + public Dimension preferredLayoutSize(Container target) { | |
| 702 | + synchronized (target.getTreeLock()) { | |
| 703 | + Dimension dim = new Dimension(0, 0); | |
| 704 | + | |
| 705 | + boolean ltr = target.getComponentOrientation().isLeftToRight(); | |
| 706 | + Component c = null; | |
| 707 | + | |
| 708 | + if ((c=getChild(EAST,ltr)) != null) { | |
| 709 | + Dimension d = c.getPreferredSize(); | |
| 710 | + dim.width += d.width + hgap; | |
| 711 | + dim.height = Math.max(d.height, dim.height); | |
| 712 | + } | |
| 713 | + if ((c=getChild(WEST,ltr)) != null) { | |
| 714 | + Dimension d = c.getPreferredSize(); | |
| 715 | + dim.width += d.width + hgap; | |
| 716 | + dim.height = Math.max(d.height, dim.height); | |
| 717 | + } | |
| 718 | + if ((c=getChild(CENTER,ltr)) != null) { | |
| 719 | + Dimension d = c.getPreferredSize(); | |
| 720 | + dim.width += d.width; | |
| 721 | + dim.height = Math.max(d.height, dim.height); | |
| 722 | + } | |
| 723 | + if ((c=getChild(NORTH,ltr)) != null) { | |
| 724 | + Dimension d = c.getPreferredSize(); | |
| 725 | + dim.width = Math.max(d.width, dim.width); | |
| 726 | + dim.height += d.height + vgap; | |
| 727 | + } | |
| 728 | + if ((c=getChild(SOUTH,ltr)) != null) { | |
| 729 | + Dimension d = c.getPreferredSize(); | |
| 730 | + dim.width = Math.max(d.width, dim.width); | |
| 731 | + dim.height += d.height + vgap; | |
| 732 | + } | |
| 733 | + | |
| 734 | + Insets insets = target.getInsets(); | |
| 735 | + dim.width += insets.left + insets.right; | |
| 736 | + dim.height += insets.top + insets.bottom; | |
| 737 | + | |
| 738 | + return dim; | |
| 739 | + } | |
| 740 | + } | |
| 741 | + | |
| 742 | + /** | |
| 743 | + * Returns the maximum dimensions for this layout given the components | |
| 744 | + * in the specified target container. | |
| 745 | + * @param target the component which needs to be laid out | |
| 746 | + * @see Container | |
| 747 | + * @see #minimumLayoutSize | |
| 748 | + * @see #preferredLayoutSize | |
| 749 | + */ | |
| 750 | + public Dimension maximumLayoutSize(Container target) { | |
| 751 | + return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE); | |
| 752 | + } | |
| 753 | + | |
| 754 | + /** | |
| 755 | + * Returns the alignment along the x axis. This specifies how | |
| 756 | + * the component would like to be aligned relative to other | |
| 757 | + * components. The value should be a number between 0 and 1 | |
| 758 | + * where 0 represents alignment along the origin, 1 is aligned | |
| 759 | + * the furthest away from the origin, 0.5 is centered, etc. | |
| 760 | + */ | |
| 761 | + public float getLayoutAlignmentX(Container parent) { | |
| 762 | + return 0.5f; | |
| 763 | + } | |
| 764 | + | |
| 765 | + /** | |
| 766 | + * Returns the alignment along the y axis. This specifies how | |
| 767 | + * the component would like to be aligned relative to other | |
| 768 | + * components. The value should be a number between 0 and 1 | |
| 769 | + * where 0 represents alignment along the origin, 1 is aligned | |
| 770 | + * the furthest away from the origin, 0.5 is centered, etc. | |
| 771 | + */ | |
| 772 | + public float getLayoutAlignmentY(Container parent) { | |
| 773 | + return 0.5f; | |
| 774 | + } | |
| 775 | + | |
| 776 | + /** | |
| 777 | + * Invalidates the layout, indicating that if the layout manager | |
| 778 | + * has cached information it should be discarded. | |
| 779 | + */ | |
| 780 | + public void invalidateLayout(Container target) { | |
| 781 | + } | |
| 782 | + | |
| 783 | + /** | |
| 784 | + * Lays out the container argument using this border layout. | |
| 785 | + * <p> | |
| 786 | + * This method actually reshapes the components in the specified | |
| 787 | + * container in order to satisfy the constraints of this | |
| 788 | + * <code>BorderLayout</code> object. The <code>NORTH</code> | |
| 789 | + * and <code>SOUTH</code> components, if any, are placed at | |
| 790 | + * the top and bottom of the container, respectively. The | |
| 791 | + * <code>WEST</code> and <code>EAST</code> components are | |
| 792 | + * then placed on the left and right, respectively. Finally, | |
| 793 | + * the <code>CENTER</code> object is placed in any remaining | |
| 794 | + * space in the middle. | |
| 795 | + * <p> | |
| 796 | + * Most applications do not call this method directly. This method | |
| 797 | + * is called when a container calls its <code>doLayout</code> method. | |
| 798 | + * @param target the container in which to do the layout. | |
| 799 | + * @see java.awt.Container | |
| 800 | + * @see java.awt.Container#doLayout() | |
| 801 | + */ | |
| 802 | + public void layoutContainer(Container target) { | |
| 803 | + synchronized (target.getTreeLock()) { | |
| 804 | + Insets insets = target.getInsets(); | |
| 805 | + int top = insets.top; | |
| 806 | + int bottom = target.height - insets.bottom; | |
| 807 | + int left = insets.left; | |
| 808 | + int right = target.width - insets.right; | |
| 809 | + | |
| 810 | + boolean ltr = target.getComponentOrientation().isLeftToRight(); | |
| 811 | + Component c = null; | |
| 812 | + | |
| 813 | + if ((c=getChild(NORTH,ltr)) != null) { | |
| 814 | + c.setSize(right - left, c.height); | |
| 815 | + Dimension d = c.getPreferredSize(); | |
| 816 | + c.setBounds(left, top, right - left, d.height); | |
| 817 | + top += d.height + vgap; | |
| 818 | + } | |
| 819 | + if ((c=getChild(SOUTH,ltr)) != null) { | |
| 820 | + c.setSize(right - left, c.height); | |
| 821 | + Dimension d = c.getPreferredSize(); | |
| 822 | + c.setBounds(left, bottom - d.height, right - left, d.height); | |
| 823 | + bottom -= d.height + vgap; | |
| 824 | + } | |
| 825 | + if ((c=getChild(EAST,ltr)) != null) { | |
| 826 | + c.setSize(c.width, bottom - top); | |
| 827 | + Dimension d = c.getPreferredSize(); | |
| 828 | + c.setBounds(right - d.width, top, d.width, bottom - top); | |
| 829 | + right -= d.width + hgap; | |
| 830 | + } | |
| 831 | + if ((c=getChild(WEST,ltr)) != null) { | |
| 832 | + c.setSize(c.width, bottom - top); | |
| 833 | + Dimension d = c.getPreferredSize(); | |
| 834 | + c.setBounds(left, top, d.width, bottom - top); | |
| 835 | + left += d.width + hgap; | |
| 836 | + } | |
| 837 | + if ((c=getChild(CENTER,ltr)) != null) { | |
| 838 | + c.setBounds(left, top, right - left, bottom - top); | |
| 839 | + } | |
| 840 | + } | |
| 841 | + } | |
| 842 | + | |
| 843 | + /** | |
| 844 | + * Get the component that corresponds to the given constraint location | |
| 845 | + * | |
| 846 | + * @param key The desired absolute position, | |
| 847 | + * either NORTH, SOUTH, EAST, or WEST. | |
| 848 | + * @param ltr Is the component line direction left-to-right? | |
| 849 | + */ | |
| 850 | + private Component getChild(String key, boolean ltr) { | |
| 851 | + Component result = null; | |
| 852 | + | |
| 853 | + if (key == NORTH) { | |
| 854 | + result = (firstLine != null) ? firstLine : north; | |
| 855 | + } | |
| 856 | + else if (key == SOUTH) { | |
| 857 | + result = (lastLine != null) ? lastLine : south; | |
| 858 | + } | |
| 859 | + else if (key == WEST) { | |
| 860 | + result = ltr ? firstItem : lastItem; | |
| 861 | + if (result == null) { | |
| 862 | + result = west; | |
| 863 | + } | |
| 864 | + } | |
| 865 | + else if (key == EAST) { | |
| 866 | + result = ltr ? lastItem : firstItem; | |
| 867 | + if (result == null) { | |
| 868 | + result = east; | |
| 869 | + } | |
| 870 | + } | |
| 871 | + else if (key == CENTER) { | |
| 872 | + result = center; | |
| 873 | + } | |
| 874 | + if (result != null && !result.visible) { | |
| 875 | + result = null; | |
| 876 | + } | |
| 877 | + return result; | |
| 878 | + } | |
| 879 | + | |
| 880 | + /** | |
| 881 | + * Returns a string representation of the state of this border layout. | |
| 882 | + * @return a string representation of this border layout. | |
| 883 | + */ | |
| 884 | + public String toString() { | |
| 885 | + return getClass().getName() + "[hgap=" + hgap + ",vgap=" + vgap + "]"; | |
| 886 | + } | |
| 887 | +} | |