J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2005 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.imageio.metadata; |
| 27 | |
| 28 | import org.w3c.dom.Node; |
| 29 | import java.lang.reflect.Method; |
| 30 | |
| 31 | /** |
| 32 | * An abstract class to be extended by objects that represent metadata |
| 33 | * (non-image data) associated with images and streams. Plug-ins |
| 34 | * represent metadata using opaque, plug-in specific objects. These |
| 35 | * objects, however, provide the ability to access their internal |
| 36 | * information as a tree of <code>IIOMetadataNode</code> objects that |
| 37 | * support the XML DOM interfaces as well as additional interfaces for |
| 38 | * storing non-textual data and retrieving information about legal |
| 39 | * data values. The format of such trees is plug-in dependent, but |
| 40 | * plug-ins may choose to support a plug-in neutral format described |
| 41 | * below. A single plug-in may support multiple metadata formats, |
| 42 | * whose names maybe determined by calling |
| 43 | * <code>getMetadataFormatNames</code>. The plug-in may also support |
| 44 | * a single special format, referred to as the "native" format, which |
| 45 | * is designed to encode its metadata losslessly. This format will |
| 46 | * typically be designed specifically to work with a specific file |
| 47 | * format, so that images may be loaded and saved in the same format |
| 48 | * with no loss of metadata, but may be less useful for transfering |
| 49 | * metadata between an <code>ImageReader</code> and an |
| 50 | * <code>ImageWriter</code> for different image formats. To convert |
| 51 | * between two native formats as losslessly as the image file formats |
| 52 | * will allow, an <code>ImageTranscoder</code> object must be used. |
| 53 | * |
| 54 | * @see javax.imageio.ImageReader#getImageMetadata |
| 55 | * @see javax.imageio.ImageReader#getStreamMetadata |
| 56 | * @see javax.imageio.ImageReader#readAll |
| 57 | * @see javax.imageio.ImageWriter#getDefaultStreamMetadata |
| 58 | * @see javax.imageio.ImageWriter#getDefaultImageMetadata |
| 59 | * @see javax.imageio.ImageWriter#write |
| 60 | * @see javax.imageio.ImageWriter#convertImageMetadata |
| 61 | * @see javax.imageio.ImageWriter#convertStreamMetadata |
| 62 | * @see javax.imageio.IIOImage |
| 63 | * @see javax.imageio.ImageTranscoder |
| 64 | * |
| 65 | */ |
| 66 | public abstract class IIOMetadata { |
| 67 | |
| 68 | /** |
| 69 | * A boolean indicating whether the concrete subclass supports the |
| 70 | * standard metadata format, set via the constructor. |
| 71 | */ |
| 72 | protected boolean standardFormatSupported; |
| 73 | |
| 74 | /** |
| 75 | * The name of the native metadata format for this object, |
| 76 | * initialized to <code>null</code> and set via the constructor. |
| 77 | */ |
| 78 | protected String nativeMetadataFormatName = null; |
| 79 | |
| 80 | /** |
| 81 | * The name of the class implementing <code>IIOMetadataFormat</code> |
| 82 | * and representing the native metadata format, initialized to |
| 83 | * <code>null</code> and set via the constructor. |
| 84 | */ |
| 85 | protected String nativeMetadataFormatClassName = null; |
| 86 | |
| 87 | /** |
| 88 | * An array of names of formats, other than the standard and |
| 89 | * native formats, that are supported by this plug-in, |
| 90 | * initialized to <code>null</code> and set via the constructor. |
| 91 | */ |
| 92 | protected String[] extraMetadataFormatNames = null; |
| 93 | |
| 94 | /** |
| 95 | * An array of names of classes implementing <code>IIOMetadataFormat</code> |
| 96 | * and representing the metadata formats, other than the standard and |
| 97 | * native formats, that are supported by this plug-in, |
| 98 | * initialized to <code>null</code> and set via the constructor. |
| 99 | */ |
| 100 | protected String[] extraMetadataFormatClassNames = null; |
| 101 | |
| 102 | /** |
| 103 | * An <code>IIOMetadataController</code> that is suggested for use |
| 104 | * as the controller for this <code>IIOMetadata</code> object. It |
| 105 | * may be retrieved via <code>getDefaultController</code>. To |
| 106 | * install the default controller, call |
| 107 | * <code>setController(getDefaultController())</code>. This |
| 108 | * instance variable should be set by subclasses that choose to |
| 109 | * provide their own default controller, usually a GUI, for |
| 110 | * setting parameters. |
| 111 | * |
| 112 | * @see IIOMetadataController |
| 113 | * @see #getDefaultController |
| 114 | */ |
| 115 | protected IIOMetadataController defaultController = null; |
| 116 | |
| 117 | /** |
| 118 | * The <code>IIOMetadataController</code> that will be |
| 119 | * used to provide settings for this <code>IIOMetadata</code> |
| 120 | * object when the <code>activateController</code> method |
| 121 | * is called. This value overrides any default controller, |
| 122 | * even when <code>null</code>. |
| 123 | * |
| 124 | * @see IIOMetadataController |
| 125 | * @see #setController(IIOMetadataController) |
| 126 | * @see #hasController() |
| 127 | * @see #activateController() |
| 128 | */ |
| 129 | protected IIOMetadataController controller = null; |
| 130 | |
| 131 | /** |
| 132 | * Constructs an empty <code>IIOMetadata</code> object. The |
| 133 | * subclass is responsible for suppying values for all protected |
| 134 | * instance variables that will allow any non-overridden default |
| 135 | * implemtations of methods to satisfy their contracts. For example, |
| 136 | * <code>extraMetadataFormatNames</code> should not have length 0. |
| 137 | */ |
| 138 | protected IIOMetadata() {} |
| 139 | |
| 140 | /** |
| 141 | * Constructs an <code>IIOMetadata</code> object with the given |
| 142 | * format names and format class names, as well as a boolean |
| 143 | * indicating whether the standard format is supported. |
| 144 | * |
| 145 | * <p> This constructor does not attempt to check the class names |
| 146 | * for validity. Invalid class names may cause exceptions in |
| 147 | * subsequent calls to <code>getMetadataFormat</code>. |
| 148 | * |
| 149 | * @param standardMetadataFormatSupported <code>true</code> if |
| 150 | * this object can return or accept a DOM tree using the standard |
| 151 | * metadata format. |
| 152 | * @param nativeMetadataFormatName the name of the native metadata |
| 153 | * format, as a <code>String</code>, or <code>null</code> if there |
| 154 | * is no native format. |
| 155 | * @param nativeMetadataFormatClassName the name of the class of |
| 156 | * the native metadata format, or <code>null</code> if there is |
| 157 | * no native format. |
| 158 | * @param extraMetadataFormatNames an array of <code>String</code>s |
| 159 | * indicating additional formats supported by this object, or |
| 160 | * <code>null</code> if there are none. |
| 161 | * @param extraMetadataFormatClassNames an array of <code>String</code>s |
| 162 | * indicating the class names of any additional formats supported by |
| 163 | * this object, or <code>null</code> if there are none. |
| 164 | * |
| 165 | * @exception IllegalArgumentException if |
| 166 | * <code>extraMetadataFormatNames</code> has length 0. |
| 167 | * @exception IllegalArgumentException if |
| 168 | * <code>extraMetadataFormatNames</code> and |
| 169 | * <code>extraMetadataFormatClassNames</code> are neither both |
| 170 | * <code>null</code>, nor of the same length. |
| 171 | */ |
| 172 | protected IIOMetadata(boolean standardMetadataFormatSupported, |
| 173 | String nativeMetadataFormatName, |
| 174 | String nativeMetadataFormatClassName, |
| 175 | String[] extraMetadataFormatNames, |
| 176 | String[] extraMetadataFormatClassNames) { |
| 177 | this.standardFormatSupported = standardMetadataFormatSupported; |
| 178 | this.nativeMetadataFormatName = nativeMetadataFormatName; |
| 179 | this.nativeMetadataFormatClassName = nativeMetadataFormatClassName; |
| 180 | if (extraMetadataFormatNames != null) { |
| 181 | if (extraMetadataFormatNames.length == 0) { |
| 182 | throw new IllegalArgumentException |
| 183 | ("extraMetadataFormatNames.length == 0!"); |
| 184 | } |
| 185 | if (extraMetadataFormatClassNames == null) { |
| 186 | throw new IllegalArgumentException |
| 187 | ("extraMetadataFormatNames != null && extraMetadataFormatClassNames == null!"); |
| 188 | } |
| 189 | if (extraMetadataFormatClassNames.length != |
| 190 | extraMetadataFormatNames.length) { |
| 191 | throw new IllegalArgumentException |
| 192 | ("extraMetadataFormatClassNames.length != extraMetadataFormatNames.length!"); |
| 193 | } |
| 194 | this.extraMetadataFormatNames = |
| 195 | (String[]) extraMetadataFormatNames.clone(); |
| 196 | this.extraMetadataFormatClassNames = |
| 197 | (String[]) extraMetadataFormatClassNames.clone(); |
| 198 | } else { |
| 199 | if (extraMetadataFormatClassNames != null) { |
| 200 | throw new IllegalArgumentException |
| 201 | ("extraMetadataFormatNames == null && extraMetadataFormatClassNames != null!"); |
| 202 | } |
| 203 | } |
| 204 | } |
| 205 | |
| 206 | /** |
| 207 | * Returns <code>true</code> if the standard metadata format is |
| 208 | * supported by <code>getMetadataFormat</code>, |
| 209 | * <code>getAsTree</code>, <code>setFromTree</code>, and |
| 210 | * <code>mergeTree</code>. |
| 211 | * |
| 212 | * <p> The default implementation returns the value of the |
| 213 | * <code>standardFormatSupported</code> instance variable. |
| 214 | * |
| 215 | * @return <code>true</code> if the standard metadata format |
| 216 | * is supported. |
| 217 | * |
| 218 | * @see #getAsTree |
| 219 | * @see #setFromTree |
| 220 | * @see #mergeTree |
| 221 | * @see #getMetadataFormat |
| 222 | */ |
| 223 | public boolean isStandardMetadataFormatSupported() { |
| 224 | return standardFormatSupported; |
| 225 | } |
| 226 | |
| 227 | /** |
| 228 | * Returns <code>true</code> if this object does not support the |
| 229 | * <code>mergeTree</code>, <code>setFromTree</code>, and |
| 230 | * <code>reset</code> methods. |
| 231 | * |
| 232 | * @return true if this <code>IIOMetadata</code> object cannot be |
| 233 | * modified. |
| 234 | */ |
| 235 | public abstract boolean isReadOnly(); |
| 236 | |
| 237 | /** |
| 238 | * Returns the name of the "native" metadata format for this |
| 239 | * plug-in, which typically allows for lossless encoding and |
| 240 | * transmission of the metadata stored in the format handled by |
| 241 | * this plug-in. If no such format is supported, |
| 242 | * <code>null</code>will be returned. |
| 243 | * |
| 244 | * <p> The structure and contents of the "native" metadata format |
| 245 | * are defined by the plug-in that created this |
| 246 | * <code>IIOMetadata</code> object. Plug-ins for simple formats |
| 247 | * will usually create a dummy node for the root, and then a |
| 248 | * series of child nodes representing individual tags, chunks, or |
| 249 | * keyword/value pairs. A plug-in may choose whether or not to |
| 250 | * document its native format. |
| 251 | * |
| 252 | * <p> The default implementation returns the value of the |
| 253 | * <code>nativeMetadataFormatName</code> instance variable. |
| 254 | * |
| 255 | * @return the name of the native format, or <code>null</code>. |
| 256 | * |
| 257 | * @see #getExtraMetadataFormatNames |
| 258 | * @see #getMetadataFormatNames |
| 259 | */ |
| 260 | public String getNativeMetadataFormatName() { |
| 261 | return nativeMetadataFormatName; |
| 262 | } |
| 263 | |
| 264 | /** |
| 265 | * Returns an array of <code>String</code>s containing the names |
| 266 | * of additional metadata formats, other than the native and standard |
| 267 | * formats, recognized by this plug-in's |
| 268 | * <code>getAsTree</code>, <code>setFromTree</code>, and |
| 269 | * <code>mergeTree</code> methods. If there are no such additional |
| 270 | * formats, <code>null</code> is returned. |
| 271 | * |
| 272 | * <p> The default implementation returns a clone of the |
| 273 | * <code>extraMetadataFormatNames</code> instance variable. |
| 274 | * |
| 275 | * @return an array of <code>String</code>s with length at least |
| 276 | * 1, or <code>null</code>. |
| 277 | * |
| 278 | * @see #getAsTree |
| 279 | * @see #setFromTree |
| 280 | * @see #mergeTree |
| 281 | * @see #getNativeMetadataFormatName |
| 282 | * @see #getMetadataFormatNames |
| 283 | */ |
| 284 | public String[] getExtraMetadataFormatNames() { |
| 285 | if (extraMetadataFormatNames == null) { |
| 286 | return null; |
| 287 | } |
| 288 | return (String[])extraMetadataFormatNames.clone(); |
| 289 | } |
| 290 | |
| 291 | /** |
| 292 | * Returns an array of <code>String</code>s containing the names |
| 293 | * of all metadata formats, including the native and standard |
| 294 | * formats, recognized by this plug-in's <code>getAsTree</code>, |
| 295 | * <code>setFromTree</code>, and <code>mergeTree</code> methods. |
| 296 | * If there are no such formats, <code>null</code> is returned. |
| 297 | * |
| 298 | * <p> The default implementation calls |
| 299 | * <code>getNativeMetadataFormatName</code>, |
| 300 | * <code>isStandardMetadataFormatSupported</code>, and |
| 301 | * <code>getExtraMetadataFormatNames</code> and returns the |
| 302 | * combined results. |
| 303 | * |
| 304 | * @return an array of <code>String</code>s. |
| 305 | * |
| 306 | * @see #getNativeMetadataFormatName |
| 307 | * @see #isStandardMetadataFormatSupported |
| 308 | * @see #getExtraMetadataFormatNames |
| 309 | */ |
| 310 | public String[] getMetadataFormatNames() { |
| 311 | String nativeName = getNativeMetadataFormatName(); |
| 312 | String standardName = isStandardMetadataFormatSupported() ? |
| 313 | IIOMetadataFormatImpl.standardMetadataFormatName : null; |
| 314 | String[] extraNames = getExtraMetadataFormatNames(); |
| 315 | |
| 316 | int numFormats = 0; |
| 317 | if (nativeName != null) { |
| 318 | ++numFormats; |
| 319 | } |
| 320 | if (standardName != null) { |
| 321 | ++numFormats; |
| 322 | } |
| 323 | if (extraNames != null) { |
| 324 | numFormats += extraNames.length; |
| 325 | } |
| 326 | if (numFormats == 0) { |
| 327 | return null; |
| 328 | } |
| 329 | |
| 330 | String[] formats = new String[numFormats]; |
| 331 | int index = 0; |
| 332 | if (nativeName != null) { |
| 333 | formats[index++] = nativeName; |
| 334 | } |
| 335 | if (standardName != null) { |
| 336 | formats[index++] = standardName; |
| 337 | } |
| 338 | if (extraNames != null) { |
| 339 | for (int i = 0; i < extraNames.length; i++) { |
| 340 | formats[index++] = extraNames[i]; |
| 341 | } |
| 342 | } |
| 343 | |
| 344 | return formats; |
| 345 | } |
| 346 | |
| 347 | /** |
| 348 | * Returns an <code>IIOMetadataFormat</code> object describing the |
| 349 | * given metadata format, or <code>null</code> if no description |
| 350 | * is available. The supplied name must be one of those returned |
| 351 | * by <code>getMetadataFormatNames</code> (<i>i.e.</i>, either the |
| 352 | * native format name, the standard format name, or one of those |
| 353 | * returned by <code>getExtraMetadataFormatNames</code>). |
| 354 | * |
| 355 | * <p> The default implementation checks the name against the |
| 356 | * global standard metadata format name, and returns that format |
| 357 | * if it is supported. Otherwise, it checks against the native |
| 358 | * format names followed by any additional format names. If a |
| 359 | * match is found, it retrieves the name of the |
| 360 | * <code>IIOMetadataFormat</code> class from |
| 361 | * <code>nativeMetadataFormatClassName</code> or |
| 362 | * <code>extraMetadataFormatClassNames</code> as appropriate, and |
| 363 | * constructs an instance of that class using its |
| 364 | * <code>getInstance</code> method. |
| 365 | * |
| 366 | * @param formatName the desired metadata format. |
| 367 | * |
| 368 | * @return an <code>IIOMetadataFormat</code> object. |
| 369 | * |
| 370 | * @exception IllegalArgumentException if <code>formatName</code> |
| 371 | * is <code>null</code> or is not one of the names recognized by |
| 372 | * the plug-in. |
| 373 | * @exception IllegalStateException if the class corresponding to |
| 374 | * the format name cannot be loaded. |
| 375 | */ |
| 376 | public IIOMetadataFormat getMetadataFormat(String formatName) { |
| 377 | if (formatName == null) { |
| 378 | throw new IllegalArgumentException("formatName == null!"); |
| 379 | } |
| 380 | if (standardFormatSupported |
| 381 | && formatName.equals |
| 382 | (IIOMetadataFormatImpl.standardMetadataFormatName)) { |
| 383 | return IIOMetadataFormatImpl.getStandardFormatInstance(); |
| 384 | } |
| 385 | String formatClassName = null; |
| 386 | if (formatName.equals(nativeMetadataFormatName)) { |
| 387 | formatClassName = nativeMetadataFormatClassName; |
| 388 | } else if (extraMetadataFormatNames != null) { |
| 389 | for (int i = 0; i < extraMetadataFormatNames.length; i++) { |
| 390 | if (formatName.equals(extraMetadataFormatNames[i])) { |
| 391 | formatClassName = extraMetadataFormatClassNames[i]; |
| 392 | break; // out of for |
| 393 | } |
| 394 | } |
| 395 | } |
| 396 | if (formatClassName == null) { |
| 397 | throw new IllegalArgumentException("Unsupported format name"); |
| 398 | } |
| 399 | try { |
| 400 | Class cls = null; |
| 401 | final Object o = this; |
| 402 | |
| 403 | // firstly we try to use classloader used for loading |
| 404 | // the IIOMetadata implemantation for this plugin. |
| 405 | ClassLoader loader = (ClassLoader) |
| 406 | java.security.AccessController.doPrivileged( |
| 407 | new java.security.PrivilegedAction() { |
| 408 | public Object run() { |
| 409 | return o.getClass().getClassLoader(); |
| 410 | } |
| 411 | }); |
| 412 | |
| 413 | try { |
| 414 | cls = Class.forName(formatClassName, true, |
| 415 | loader); |
| 416 | } catch (ClassNotFoundException e) { |
| 417 | // we failed to load IIOMetadataFormat class by |
| 418 | // using IIOMetadata classloader.Next try is to |
| 419 | // use thread context classloader. |
| 420 | loader = (ClassLoader) |
| 421 | java.security.AccessController.doPrivileged( |
| 422 | new java.security.PrivilegedAction() { |
| 423 | public Object run() { |
| 424 | return Thread.currentThread().getContextClassLoader(); |
| 425 | } |
| 426 | }); |
| 427 | try { |
| 428 | cls = Class.forName(formatClassName, true, |
| 429 | loader); |
| 430 | } catch (ClassNotFoundException e1) { |
| 431 | // finally we try to use system classloader in case |
| 432 | // if we failed to load IIOMetadataFormat implementation |
| 433 | // class above. |
| 434 | cls = Class.forName(formatClassName, true, |
| 435 | ClassLoader.getSystemClassLoader()); |
| 436 | } |
| 437 | } |
| 438 | |
| 439 | Method meth = cls.getMethod("getInstance"); |
| 440 | return (IIOMetadataFormat) meth.invoke(null); |
| 441 | } catch (Exception e) { |
| 442 | RuntimeException ex = |
| 443 | new IllegalStateException ("Can't obtain format"); |
| 444 | ex.initCause(e); |
| 445 | throw ex; |
| 446 | } |
| 447 | |
| 448 | } |
| 449 | |
| 450 | /** |
| 451 | * Returns an XML DOM <code>Node</code> object that represents the |
| 452 | * root of a tree of metadata contained within this object |
| 453 | * according to the conventions defined by a given metadata |
| 454 | * format. |
| 455 | * |
| 456 | * <p> The names of the available metadata formats may be queried |
| 457 | * using the <code>getMetadataFormatNames</code> method. |
| 458 | * |
| 459 | * @param formatName the desired metadata format. |
| 460 | * |
| 461 | * @return an XML DOM <code>Node</code> object forming the |
| 462 | * root of a tree. |
| 463 | * |
| 464 | * @exception IllegalArgumentException if <code>formatName</code> |
| 465 | * is <code>null</code> or is not one of the names returned by |
| 466 | * <code>getMetadataFormatNames</code>. |
| 467 | * |
| 468 | * @see #getMetadataFormatNames |
| 469 | * @see #setFromTree |
| 470 | * @see #mergeTree |
| 471 | */ |
| 472 | public abstract Node getAsTree(String formatName); |
| 473 | |
| 474 | /** |
| 475 | * Alters the internal state of this <code>IIOMetadata</code> |
| 476 | * object from a tree of XML DOM <code>Node</code>s whose syntax |
| 477 | * is defined by the given metadata format. The previous state is |
| 478 | * altered only as necessary to accomodate the nodes that are |
| 479 | * present in the given tree. If the tree structure or contents |
| 480 | * are invalid, an <code>IIOInvalidTreeException</code> will be |
| 481 | * thrown. |
| 482 | * |
| 483 | * <p> As the semantics of how a tree or subtree may be merged with |
| 484 | * another tree are completely format-specific, plug-in authors may |
| 485 | * implement this method in whatever manner is most appropriate for |
| 486 | * the format, including simply replacing all existing state with the |
| 487 | * contents of the given tree. |
| 488 | * |
| 489 | * @param formatName the desired metadata format. |
| 490 | * @param root an XML DOM <code>Node</code> object forming the |
| 491 | * root of a tree. |
| 492 | * |
| 493 | * @exception IllegalStateException if this object is read-only. |
| 494 | * @exception IllegalArgumentException if <code>formatName</code> |
| 495 | * is <code>null</code> or is not one of the names returned by |
| 496 | * <code>getMetadataFormatNames</code>. |
| 497 | * @exception IllegalArgumentException if <code>root</code> is |
| 498 | * <code>null</code>. |
| 499 | * @exception IIOInvalidTreeException if the tree cannot be parsed |
| 500 | * successfully using the rules of the given format. |
| 501 | * |
| 502 | * @see #getMetadataFormatNames |
| 503 | * @see #getAsTree |
| 504 | * @see #setFromTree |
| 505 | */ |
| 506 | public abstract void mergeTree(String formatName, Node root) |
| 507 | throws IIOInvalidTreeException; |
| 508 | |
| 509 | /** |
| 510 | * Returns an <code>IIOMetadataNode</code> representing the chroma |
| 511 | * information of the standard <code>javax_imageio_1.0</code> |
| 512 | * metadata format, or <code>null</code> if no such information is |
| 513 | * available. This method is intended to be called by the utility |
| 514 | * routine <code>getStandardTree</code>. |
| 515 | * |
| 516 | * <p> The default implementation returns <code>null</code>. |
| 517 | * |
| 518 | * <p> Subclasses should override this method to produce an |
| 519 | * appropriate subtree if they wish to support the standard |
| 520 | * metadata format. |
| 521 | * |
| 522 | * @return an <code>IIOMetadataNode</code>, or <code>null</code>. |
| 523 | * |
| 524 | * @see #getStandardTree |
| 525 | */ |
| 526 | protected IIOMetadataNode getStandardChromaNode() { |
| 527 | return null; |
| 528 | } |
| 529 | |
| 530 | /** |
| 531 | * Returns an <code>IIOMetadataNode</code> representing the |
| 532 | * compression information of the standard |
| 533 | * <code>javax_imageio_1.0</code> metadata format, or |
| 534 | * <code>null</code> if no such information is available. This |
| 535 | * method is intended to be called by the utility routine |
| 536 | * <code>getStandardTree</code>. |
| 537 | * |
| 538 | * <p> The default implementation returns <code>null</code>. |
| 539 | * |
| 540 | * <p> Subclasses should override this method to produce an |
| 541 | * appropriate subtree if they wish to support the standard |
| 542 | * metadata format. |
| 543 | * |
| 544 | * @return an <code>IIOMetadataNode</code>, or <code>null</code>. |
| 545 | * |
| 546 | * @see #getStandardTree |
| 547 | */ |
| 548 | protected IIOMetadataNode getStandardCompressionNode() { |
| 549 | return null; |
| 550 | } |
| 551 | |
| 552 | /** |
| 553 | * Returns an <code>IIOMetadataNode</code> representing the data |
| 554 | * format information of the standard |
| 555 | * <code>javax_imageio_1.0</code> metadata format, or |
| 556 | * <code>null</code> if no such information is available. This |
| 557 | * method is intended to be called by the utility routine |
| 558 | * <code>getStandardTree</code>. |
| 559 | * |
| 560 | * <p> The default implementation returns <code>null</code>. |
| 561 | * |
| 562 | * <p> Subclasses should override this method to produce an |
| 563 | * appropriate subtree if they wish to support the standard |
| 564 | * metadata format. |
| 565 | * |
| 566 | * @return an <code>IIOMetadataNode</code>, or <code>null</code>. |
| 567 | * |
| 568 | * @see #getStandardTree |
| 569 | */ |
| 570 | protected IIOMetadataNode getStandardDataNode() { |
| 571 | return null; |
| 572 | } |
| 573 | |
| 574 | /** |
| 575 | * Returns an <code>IIOMetadataNode</code> representing the |
| 576 | * dimension information of the standard |
| 577 | * <code>javax_imageio_1.0</code> metadata format, or |
| 578 | * <code>null</code> if no such information is available. This |
| 579 | * method is intended to be called by the utility routine |
| 580 | * <code>getStandardTree</code>. |
| 581 | * |
| 582 | * <p> The default implementation returns <code>null</code>. |
| 583 | * |
| 584 | * <p> Subclasses should override this method to produce an |
| 585 | * appropriate subtree if they wish to support the standard |
| 586 | * metadata format. |
| 587 | * |
| 588 | * @return an <code>IIOMetadataNode</code>, or <code>null</code>. |
| 589 | * |
| 590 | * @see #getStandardTree |
| 591 | */ |
| 592 | protected IIOMetadataNode getStandardDimensionNode() { |
| 593 | return null; |
| 594 | } |
| 595 | |
| 596 | /** |
| 597 | * Returns an <code>IIOMetadataNode</code> representing the document |
| 598 | * information of the standard <code>javax_imageio_1.0</code> |
| 599 | * metadata format, or <code>null</code> if no such information is |
| 600 | * available. This method is intended to be called by the utility |
| 601 | * routine <code>getStandardTree</code>. |
| 602 | * |
| 603 | * <p> The default implementation returns <code>null</code>. |
| 604 | * |
| 605 | * <p> Subclasses should override this method to produce an |
| 606 | * appropriate subtree if they wish to support the standard |
| 607 | * metadata format. |
| 608 | * |
| 609 | * @return an <code>IIOMetadataNode</code>, or <code>null</code>. |
| 610 | * |
| 611 | * @see #getStandardTree |
| 612 | */ |
| 613 | protected IIOMetadataNode getStandardDocumentNode() { |
| 614 | return null; |
| 615 | } |
| 616 | |
| 617 | /** |
| 618 | * Returns an <code>IIOMetadataNode</code> representing the textual |
| 619 | * information of the standard <code>javax_imageio_1.0</code> |
| 620 | * metadata format, or <code>null</code> if no such information is |
| 621 | * available. This method is intended to be called by the utility |
| 622 | * routine <code>getStandardTree</code>. |
| 623 | * |
| 624 | * <p> The default implementation returns <code>null</code>. |
| 625 | * |
| 626 | * <p> Subclasses should override this method to produce an |
| 627 | * appropriate subtree if they wish to support the standard |
| 628 | * metadata format. |
| 629 | * |
| 630 | * @return an <code>IIOMetadataNode</code>, or <code>null</code>. |
| 631 | * |
| 632 | * @see #getStandardTree |
| 633 | */ |
| 634 | protected IIOMetadataNode getStandardTextNode() { |
| 635 | return null; |
| 636 | } |
| 637 | |
| 638 | /** |
| 639 | * Returns an <code>IIOMetadataNode</code> representing the tiling |
| 640 | * information of the standard <code>javax_imageio_1.0</code> |
| 641 | * metadata format, or <code>null</code> if no such information is |
| 642 | * available. This method is intended to be called by the utility |
| 643 | * routine <code>getStandardTree</code>. |
| 644 | * |
| 645 | * <p> The default implementation returns <code>null</code>. |
| 646 | * |
| 647 | * <p> Subclasses should override this method to produce an |
| 648 | * appropriate subtree if they wish to support the standard |
| 649 | * metadata format. |
| 650 | * |
| 651 | * @return an <code>IIOMetadataNode</code>, or <code>null</code>. |
| 652 | * |
| 653 | * @see #getStandardTree |
| 654 | */ |
| 655 | protected IIOMetadataNode getStandardTileNode() { |
| 656 | return null; |
| 657 | } |
| 658 | |
| 659 | /** |
| 660 | * Returns an <code>IIOMetadataNode</code> representing the |
| 661 | * transparency information of the standard |
| 662 | * <code>javax_imageio_1.0</code> metadata format, or |
| 663 | * <code>null</code> if no such information is available. This |
| 664 | * method is intended to be called by the utility routine |
| 665 | * <code>getStandardTree</code>. |
| 666 | * |
| 667 | * <p> The default implementation returns <code>null</code>. |
| 668 | * |
| 669 | * <p> Subclasses should override this method to produce an |
| 670 | * appropriate subtree if they wish to support the standard |
| 671 | * metadata format. |
| 672 | * |
| 673 | * @return an <code>IIOMetadataNode</code>, or <code>null</code>. |
| 674 | */ |
| 675 | protected IIOMetadataNode getStandardTransparencyNode() { |
| 676 | return null; |
| 677 | } |
| 678 | |
| 679 | /** |
| 680 | * Appends a new node to an existing node, if the new node is |
| 681 | * non-<code>null</code>. |
| 682 | */ |
| 683 | private void append(IIOMetadataNode root, IIOMetadataNode node) { |
| 684 | if (node != null) { |
| 685 | root.appendChild(node); |
| 686 | } |
| 687 | } |
| 688 | |
| 689 | /** |
| 690 | * A utility method to return a tree of |
| 691 | * <code>IIOMetadataNode</code>s representing the metadata |
| 692 | * contained within this object according to the conventions of |
| 693 | * the standard <code>javax_imageio_1.0</code> metadata format. |
| 694 | * |
| 695 | * <p> This method calls the various <code>getStandard*Node</code> |
| 696 | * methods to supply each of the subtrees rooted at the children |
| 697 | * of the root node. If any of those methods returns |
| 698 | * <code>null</code>, the corresponding subtree will be omitted. |
| 699 | * If all of them return <code>null</code>, a tree consisting of a |
| 700 | * single root node will be returned. |
| 701 | * |
| 702 | * @return an <code>IIOMetadataNode</code> representing the root |
| 703 | * of a metadata tree in the <code>javax_imageio_1.0</code> |
| 704 | * format. |
| 705 | * |
| 706 | * @see #getStandardChromaNode |
| 707 | * @see #getStandardCompressionNode |
| 708 | * @see #getStandardDataNode |
| 709 | * @see #getStandardDimensionNode |
| 710 | * @see #getStandardDocumentNode |
| 711 | * @see #getStandardTextNode |
| 712 | * @see #getStandardTileNode |
| 713 | * @see #getStandardTransparencyNode |
| 714 | */ |
| 715 | protected final IIOMetadataNode getStandardTree() { |
| 716 | IIOMetadataNode root = new IIOMetadataNode |
| 717 | (IIOMetadataFormatImpl.standardMetadataFormatName); |
| 718 | append(root, getStandardChromaNode()); |
| 719 | append(root, getStandardCompressionNode()); |
| 720 | append(root, getStandardDataNode()); |
| 721 | append(root, getStandardDimensionNode()); |
| 722 | append(root, getStandardDocumentNode()); |
| 723 | append(root, getStandardTextNode()); |
| 724 | append(root, getStandardTileNode()); |
| 725 | append(root, getStandardTransparencyNode()); |
| 726 | return root; |
| 727 | } |
| 728 | |
| 729 | /** |
| 730 | * Sets the internal state of this <code>IIOMetadata</code> object |
| 731 | * from a tree of XML DOM <code>Node</code>s whose syntax is |
| 732 | * defined by the given metadata format. The previous state is |
| 733 | * discarded. If the tree's structure or contents are invalid, an |
| 734 | * <code>IIOInvalidTreeException</code> will be thrown. |
| 735 | * |
| 736 | * <p> The default implementation calls <code>reset</code> |
| 737 | * followed by <code>mergeTree(formatName, root)</code>. |
| 738 | * |
| 739 | * @param formatName the desired metadata format. |
| 740 | * @param root an XML DOM <code>Node</code> object forming the |
| 741 | * root of a tree. |
| 742 | * |
| 743 | * @exception IllegalStateException if this object is read-only. |
| 744 | * @exception IllegalArgumentException if <code>formatName</code> |
| 745 | * is <code>null</code> or is not one of the names returned by |
| 746 | * <code>getMetadataFormatNames</code>. |
| 747 | * @exception IllegalArgumentException if <code>root</code> is |
| 748 | * <code>null</code>. |
| 749 | * @exception IIOInvalidTreeException if the tree cannot be parsed |
| 750 | * successfully using the rules of the given format. |
| 751 | * |
| 752 | * @see #getMetadataFormatNames |
| 753 | * @see #getAsTree |
| 754 | * @see #mergeTree |
| 755 | */ |
| 756 | public void setFromTree(String formatName, Node root) |
| 757 | throws IIOInvalidTreeException { |
| 758 | reset(); |
| 759 | mergeTree(formatName, root); |
| 760 | } |
| 761 | |
| 762 | /** |
| 763 | * Resets all the data stored in this object to default values, |
| 764 | * usually to the state this object was in immediately after |
| 765 | * construction, though the precise semantics are plug-in specific. |
| 766 | * Note that there are many possible default values, depending on |
| 767 | * how the object was created. |
| 768 | * |
| 769 | * @exception IllegalStateException if this object is read-only. |
| 770 | * |
| 771 | * @see javax.imageio.ImageReader#getStreamMetadata |
| 772 | * @see javax.imageio.ImageReader#getImageMetadata |
| 773 | * @see javax.imageio.ImageWriter#getDefaultStreamMetadata |
| 774 | * @see javax.imageio.ImageWriter#getDefaultImageMetadata |
| 775 | */ |
| 776 | public abstract void reset(); |
| 777 | |
| 778 | /** |
| 779 | * Sets the <code>IIOMetadataController</code> to be used |
| 780 | * to provide settings for this <code>IIOMetadata</code> |
| 781 | * object when the <code>activateController</code> method |
| 782 | * is called, overriding any default controller. If the |
| 783 | * argument is <code>null</code>, no controller will be |
| 784 | * used, including any default. To restore the default, use |
| 785 | * <code>setController(getDefaultController())</code>. |
| 786 | * |
| 787 | * <p> The default implementation sets the <code>controller</code> |
| 788 | * instance variable to the supplied value. |
| 789 | * |
| 790 | * @param controller An appropriate |
| 791 | * <code>IIOMetadataController</code>, or <code>null</code>. |
| 792 | * |
| 793 | * @see IIOMetadataController |
| 794 | * @see #getController |
| 795 | * @see #getDefaultController |
| 796 | * @see #hasController |
| 797 | * @see #activateController() |
| 798 | */ |
| 799 | public void setController(IIOMetadataController controller) { |
| 800 | this.controller = controller; |
| 801 | } |
| 802 | |
| 803 | /** |
| 804 | * Returns whatever <code>IIOMetadataController</code> is currently |
| 805 | * installed. This could be the default if there is one, |
| 806 | * <code>null</code>, or the argument of the most recent call |
| 807 | * to <code>setController</code>. |
| 808 | * |
| 809 | * <p> The default implementation returns the value of the |
| 810 | * <code>controller</code> instance variable. |
| 811 | * |
| 812 | * @return the currently installed |
| 813 | * <code>IIOMetadataController</code>, or <code>null</code>. |
| 814 | * |
| 815 | * @see IIOMetadataController |
| 816 | * @see #setController |
| 817 | * @see #getDefaultController |
| 818 | * @see #hasController |
| 819 | * @see #activateController() |
| 820 | */ |
| 821 | public IIOMetadataController getController() { |
| 822 | return controller; |
| 823 | } |
| 824 | |
| 825 | /** |
| 826 | * Returns the default <code>IIOMetadataController</code>, if there |
| 827 | * is one, regardless of the currently installed controller. If |
| 828 | * there is no default controller, returns <code>null</code>. |
| 829 | * |
| 830 | * <p> The default implementation returns the value of the |
| 831 | * <code>defaultController</code> instance variable. |
| 832 | * |
| 833 | * @return the default <code>IIOMetadataController</code>, or |
| 834 | * <code>null</code>. |
| 835 | * |
| 836 | * @see IIOMetadataController |
| 837 | * @see #setController(IIOMetadataController) |
| 838 | * @see #getController |
| 839 | * @see #hasController |
| 840 | * @see #activateController() |
| 841 | */ |
| 842 | public IIOMetadataController getDefaultController() { |
| 843 | return defaultController; |
| 844 | } |
| 845 | |
| 846 | /** |
| 847 | * Returns <code>true</code> if there is a controller installed |
| 848 | * for this <code>IIOMetadata</code> object. |
| 849 | * |
| 850 | * <p> The default implementation returns <code>true</code> if the |
| 851 | * <code>getController</code> method returns a |
| 852 | * non-<code>null</code> value. |
| 853 | * |
| 854 | * @return <code>true</code> if a controller is installed. |
| 855 | * |
| 856 | * @see IIOMetadataController |
| 857 | * @see #setController(IIOMetadataController) |
| 858 | * @see #getController |
| 859 | * @see #getDefaultController |
| 860 | * @see #activateController() |
| 861 | */ |
| 862 | public boolean hasController() { |
| 863 | return (getController() != null); |
| 864 | } |
| 865 | |
| 866 | /** |
| 867 | * Activates the installed <code>IIOMetadataController</code> for |
| 868 | * this <code>IIOMetadata</code> object and returns the resulting |
| 869 | * value. When this method returns <code>true</code>, all values for this |
| 870 | * <code>IIOMetadata</code> object will be ready for the next write |
| 871 | * operation. If <code>false</code> is |
| 872 | * returned, no settings in this object will have been disturbed |
| 873 | * (<i>i.e.</i>, the user canceled the operation). |
| 874 | * |
| 875 | * <p> Ordinarily, the controller will be a GUI providing a user |
| 876 | * interface for a subclass of <code>IIOMetadata</code> for a |
| 877 | * particular plug-in. Controllers need not be GUIs, however. |
| 878 | * |
| 879 | * <p> The default implementation calls <code>getController</code> |
| 880 | * and the calls <code>activate</code> on the returned object if |
| 881 | * <code>hasController</code> returns <code>true</code>. |
| 882 | * |
| 883 | * @return <code>true</code> if the controller completed normally. |
| 884 | * |
| 885 | * @exception IllegalStateException if there is no controller |
| 886 | * currently installed. |
| 887 | * |
| 888 | * @see IIOMetadataController |
| 889 | * @see #setController(IIOMetadataController) |
| 890 | * @see #getController |
| 891 | * @see #getDefaultController |
| 892 | * @see #hasController |
| 893 | */ |
| 894 | public boolean activateController() { |
| 895 | if (!hasController()) { |
| 896 | throw new IllegalStateException("hasController() == false!"); |
| 897 | } |
| 898 | return getController().activate(this); |
| 899 | } |
| 900 | } |