src/be/nikiroo/utils/serial/SerialUtils.java

   1 package be.nikiroo.utils.serial;
   2
   3 import java.awt.image.BufferedImage;
   4 import java.io.IOException;
   5 import java.io.NotSerializableException;
   6 import java.lang.reflect.Array;
   7 import java.lang.reflect.Constructor;
   8 import java.lang.reflect.Field;
   9 import java.lang.reflect.Modifier;
  10 import java.net.URL;
  11 import java.util.HashMap;
  12 import java.util.Map;
  13 import java.util.UnknownFormatConversionException;
  14
  15 import be.nikiroo.utils.ImageUtils;
  16
  17 /**
  18  * Small class to help with serialisation.
  19  * <p>
  20  * Note that we do not support inner classes (but we do support nested classes)
  21  * and all objects require an empty constructor to be deserialised.
  22  * <p>
  23  * It is possible to add support to custom types (both the encoder and the
  24  * decoder will require the custom classes) -- see {@link CustomSerializer}.
  25  * <p>
  26  * Default supported types are:
  27  * <ul>
  28  * <li>NULL (as a null value)</li>
  29  * <li>String</li>
  30  * <li>Boolean</li>
  31  * <li>Byte</li>
  32  * <li>Character</li>
  33  * <li>Short</li>
  34  * <li>Long</li>
  35  * <li>Float</li>
  36  * <li>Double</li>
  37  * <li>Integer</li>
  38  * <li>Enum (any enum whose name and value is known by the caller)</li>
  39  * <li>java.awt.image.BufferedImage (as a {@link CustomSerializer})</li>
  40  * <li>An array of the above (as a {@link CustomSerializer})</li>
  41  * <li>URL</li>
  42  * </ul>
  43  *
  44  * @author niki
  45  */
  46 public class SerialUtils {
  47         private static Map<String, CustomSerializer> customTypes;
  48
  49         static {
  50                 customTypes = new HashMap<String, CustomSerializer>();
  51
  52                 // Array types:
  53                 customTypes.put("[]", new CustomSerializer() {
  54                         @Override
  55                         protected String toString(Object value) {
  56                                 String type = value.getClass().getCanonicalName();
  57                                 type = type.substring(0, type.length() - 2); // remove the []
  58
  59                                 StringBuilder builder = new StringBuilder();
  60                                 builder.append(type).append("\n");
  61                                 try {
  62                                         for (int i = 0; true; i++) {
  63                                                 Object item = Array.get(value, i);
  64                                                 // encode it normally if direct value
  65                                                 if (!SerialUtils.encode(builder, item)) {
  66                                                         try {
  67                                                                 // use ZIP: if not
  68                                                                 builder.append(new Exporter().append(item)
  69                                                                                 .toString(true));
  70                                                         } catch (NotSerializableException e) {
  71                                                                 throw new UnknownFormatConversionException(e
  72                                                                                 .getMessage());
  73                                                         }
  74                                                 }
  75                                                 builder.append("\n");
  76                                         }
  77                                 } catch (ArrayIndexOutOfBoundsException e) {
  78                                         // Done.
  79                                 }
  80
  81                                 return builder.toString();
  82                         }
  83
  84                         @Override
  85                         protected String getType() {
  86                                 return "[]";
  87                         }
  88
  89                         @Override
  90                         protected Object fromString(String content) throws IOException {
  91                                 String[] tab = content.split("\n");
  92
  93                                 try {
  94                                         Object array = Array.newInstance(
  95                                                         SerialUtils.getClass(tab[0]), tab.length - 1);
  96                                         for (int i = 1; i < tab.length; i++) {
  97                                                 Object value = new Importer().read(tab[i]).getValue();
  98                                                 Array.set(array, i - 1, value);
  99                                         }
 100
 101                                         return array;
 102                                 } catch (Exception e) {
 103                                         if (e instanceof IOException) {
 104                                                 throw (IOException) e;
 105                                         }
 106                                         throw new IOException(e.getMessage());
 107                                 }
 108                         }
 109                 });
 110
 111                 // URL:
 112                 customTypes.put("java.net.URL", new CustomSerializer() {
 113                         @Override
 114                         protected String toString(Object value) {
 115                                 if (value != null) {
 116                                         return ((URL) value).toString();
 117                                 }
 118                                 return null;
 119                         }
 120
 121                         @Override
 122                         protected Object fromString(String content) throws IOException {
 123                                 if (content != null) {
 124                                         return new URL(content);
 125                                 }
 126                                 return null;
 127                         }
 128
 129                         @Override
 130                         protected String getType() {
 131                                 return "java.net.URL";
 132                         }
 133                 });
 134
 135                 // Images (this is currently the only supported image type by default)
 136                 customTypes.put("java.awt.image.BufferedImage", new CustomSerializer() {
 137                         @Override
 138                         protected String toString(Object value) {
 139                                 try {
 140                                         return ImageUtils.toBase64((BufferedImage) value);
 141                                 } catch (IOException e) {
 142                                         throw new UnknownFormatConversionException(e.getMessage());
 143                                 }
 144                         }
 145
 146                         @Override
 147                         protected String getType() {
 148                                 return "java.awt.image.BufferedImage";
 149                         }
 150
 151                         @Override
 152                         protected Object fromString(String content) {
 153                                 try {
 154                                         return ImageUtils.fromBase64(content);
 155                                 } catch (IOException e) {
 156                                         throw new UnknownFormatConversionException(e.getMessage());
 157                                 }
 158                         }
 159                 });
 160         }
 161
 162         /**
 163          * Create an empty object of the given type.
 164          *
 165          * @param type
 166          *            the object type (its class name)
 167          *
 168          * @return the new object
 169          *
 170          * @throws ClassNotFoundException
 171          *             if the class cannot be found
 172          * @throws NoSuchMethodException
 173          *             if the given class is not compatible with this code
 174          */
 175         public static Object createObject(String type)
 176                         throws ClassNotFoundException, NoSuchMethodException {
 177
 178                 try {
 179                         Class<?> clazz = getClass(type);
 180                         String className = clazz.getName();
 181                         Object[] args = null;
 182                         Constructor<?> ctor = null;
 183                         if (className.contains("$")) {
 184                                 Object javaParent = createObject(className.substring(0,
 185                                                 className.lastIndexOf('$')));
 186                                 args = new Object[] { javaParent };
 187                                 ctor = clazz.getDeclaredConstructor(new Class[] { javaParent
 188                                                 .getClass() });
 189                         } else {
 190                                 args = new Object[] {};
 191                                 ctor = clazz.getDeclaredConstructor();
 192                         }
 193
 194                         ctor.setAccessible(true);
 195                         return ctor.newInstance(args);
 196                 } catch (ClassNotFoundException e) {
 197                         throw e;
 198                 } catch (NoSuchMethodException e) {
 199                         throw e;
 200                 } catch (Exception e) {
 201                         throw new NoSuchMethodException("Cannot instantiate: " + type);
 202                 }
 203         }
 204
 205         /**
 206          * Insert a custom serialiser that will take precedence over the default one
 207          * or the target class.
 208          *
 209          * @param serializer
 210          *            the custom serialiser
 211          */
 212         static public void addCustomSerializer(CustomSerializer serializer) {
 213                 customTypes.put(serializer.getType(), serializer);
 214         }
 215
 216         /**
 217          * Serialise the given object into this {@link StringBuilder}.
 218          * <p>
 219          * <b>Important: </b>If the operation fails (with a
 220          * {@link NotSerializableException}), the {@link StringBuilder} will be
 221          * corrupted (will contain bad, most probably not importable data).
 222          *
 223          * @param builder
 224          *            the output {@link StringBuilder} to serialise to
 225          * @param o
 226          *            the object to serialise
 227          * @param map
 228          *            the map of already serialised objects (if the given object or
 229          *            one of its descendant is already present in it, only an ID
 230          *            will be serialised)
 231          *
 232          * @throws NotSerializableException
 233          *             if the object cannot be serialised (in this case, the
 234          *             {@link StringBuilder} can contain bad, most probably not
 235          *             importable data)
 236          */
 237         static void append(StringBuilder builder, Object o, Map<Integer, Object> map)
 238                         throws NotSerializableException {
 239
 240                 Field[] fields = new Field[] {};
 241                 String type = "";
 242                 String id = "NULL";
 243
 244                 if (o != null) {
 245                         int hash = System.identityHashCode(o);
 246                         fields = o.getClass().getDeclaredFields();
 247                         type = o.getClass().getCanonicalName();
 248                         if (type == null) {
 249                                 throw new NotSerializableException(
 250                                                 String.format(
 251                                                                 "Cannot find the class for this object: %s (it could be an inner class, which is not supported)",
 252                                                                 o));
 253                         }
 254                         id = Integer.toString(hash);
 255                         if (map.containsKey(hash)) {
 256                                 fields = new Field[] {};
 257                         } else {
 258                                 map.put(hash, o);
 259                         }
 260                 }
 261
 262                 builder.append("{\nREF ").append(type).append("@").append(id)
 263                                 .append(":");
 264                 if (!encode(builder, o)) { // check if direct value
 265                         try {
 266                                 for (Field field : fields) {
 267                                         field.setAccessible(true);
 268
 269                                         if (field.getName().startsWith("this$")
 270                                                         || field.isSynthetic()
 271                                                         || (field.getModifiers() & Modifier.STATIC) == Modifier.STATIC) {
 272                                                 // Do not keep this links of nested classes
 273                                                 // Do not keep synthetic fields
 274                                                 // Do not keep final fields
 275                                                 continue;
 276                                         }
 277
 278                                         builder.append("\n");
 279                                         builder.append(field.getName());
 280                                         builder.append(":");
 281                                         Object value;
 282
 283                                         value = field.get(o);
 284
 285                                         if (!encode(builder, value)) {
 286                                                 builder.append("\n");
 287                                                 append(builder, value, map);
 288                                         }
 289                                 }
 290                         } catch (IllegalArgumentException e) {
 291                                 e.printStackTrace(); // should not happen (see
 292                                                                                 // setAccessible)
 293                         } catch (IllegalAccessException e) {
 294                                 e.printStackTrace(); // should not happen (see
 295                                                                                 // setAccessible)
 296                         }
 297                 }
 298                 builder.append("\n}");
 299         }
 300
 301         /**
 302          * Encode the object into the given builder if possible (if supported).
 303          *
 304          * @param builder
 305          *            the builder to append to
 306          * @param value
 307          *            the object to encode (can be NULL, which will be encoded)
 308          *
 309          * @return TRUE if success, FALSE if not (the content of the builder won't
 310          *         be changed in case of failure)
 311          */
 312         static boolean encode(StringBuilder builder, Object value) {
 313                 if (value == null) {
 314                         builder.append("NULL");
 315                 } else if (value.getClass().getCanonicalName().endsWith("[]")) {
 316                         return customTypes.get("[]").encode(builder, value);
 317                 } else if (customTypes.containsKey(value.getClass().getCanonicalName())) {
 318                         return customTypes.get(value.getClass().getCanonicalName())//
 319                                         .encode(builder, value);
 320                 } else if (value instanceof String) {
 321                         encodeString(builder, (String) value);
 322                 } else if (value instanceof Boolean) {
 323                         builder.append(value);
 324                 } else if (value instanceof Byte) {
 325                         builder.append(value).append('b');
 326                 } else if (value instanceof Character) {
 327                         encodeString(builder, "" + value);
 328                         builder.append('c');
 329                 } else if (value instanceof Short) {
 330                         builder.append(value).append('s');
 331                 } else if (value instanceof Integer) {
 332                         builder.append(value);
 333                 } else if (value instanceof Long) {
 334                         builder.append(value).append('L');
 335                 } else if (value instanceof Float) {
 336                         builder.append(value).append('F');
 337                 } else if (value instanceof Double) {
 338                         builder.append(value).append('d');
 339                 } else if (value instanceof Enum) {
 340                         String type = value.getClass().getCanonicalName();
 341                         builder.append(type).append(".").append(((Enum<?>) value).name())
 342                                         .append(";");
 343                 } else {
 344                         return false;
 345                 }
 346
 347                 return true;
 348         }
 349
 350         /**
 351          * Decode the data into an equivalent source object.
 352          *
 353          * @param encodedValue
 354          *            the encoded data, cannot be NULL
 355          *
 356          * @return the object (can be NULL for NULL encoded values)
 357          *
 358          * @throws IOException
 359          *             if the content cannot be converted
 360          */
 361         static Object decode(String encodedValue) throws IOException {
 362                 try {
 363                         String cut = "";
 364                         if (encodedValue.length() > 1) {
 365                                 cut = encodedValue.substring(0, encodedValue.length() - 1);
 366                         }
 367
 368                         if (CustomSerializer.isCustom(encodedValue)) {
 369                                 // custom:TYPE_NAME:"content is String-encoded"
 370                                 String type = CustomSerializer.typeOf(encodedValue);
 371                                 if (customTypes.containsKey(type)) {
 372                                         return customTypes.get(type).decode(encodedValue);
 373                                 }
 374                                 throw new IOException("Unknown custom type: " + type);
 375                         } else if (encodedValue.equals("NULL")
 376                                         || encodedValue.equals("null")) {
 377                                 return null;
 378                         } else if (encodedValue.endsWith("\"")) {
 379                                 return decodeString(encodedValue);
 380                         } else if (encodedValue.equals("true")) {
 381                                 return true;
 382                         } else if (encodedValue.equals("false")) {
 383                                 return false;
 384                         } else if (encodedValue.endsWith("b")) {
 385                                 return Byte.parseByte(cut);
 386                         } else if (encodedValue.endsWith("c")) {
 387                                 return decodeString(cut).charAt(0);
 388                         } else if (encodedValue.endsWith("s")) {
 389                                 return Short.parseShort(cut);
 390                         } else if (encodedValue.endsWith("L")) {
 391                                 return Long.parseLong(cut);
 392                         } else if (encodedValue.endsWith("F")) {
 393                                 return Float.parseFloat(cut);
 394                         } else if (encodedValue.endsWith("d")) {
 395                                 return Double.parseDouble(cut);
 396                         } else if (encodedValue.endsWith(";")) {
 397                                 return decodeEnum(encodedValue);
 398                         } else {
 399                                 return Integer.parseInt(encodedValue);
 400                         }
 401                 } catch (Exception e) {
 402                         if (e instanceof IOException) {
 403                                 throw (IOException) e;
 404                         }
 405                         throw new IOException(e.getMessage());
 406                 }
 407         }
 408
 409         /**
 410          * Return the corresponding class or throw an {@link Exception} if it
 411          * cannot.
 412          *
 413          * @param type
 414          *            the class name to look for
 415          *
 416          * @return the class (will never be NULL)
 417          *
 418          * @throws ClassNotFoundException
 419          *             if the class cannot be found
 420          * @throws NoSuchMethodException
 421          *             if the class cannot be created (usually because it or its
 422          *             enclosing class doesn't have an empty constructor)
 423          */
 424         static private Class<?> getClass(String type)
 425                         throws ClassNotFoundException, NoSuchMethodException {
 426                 Class<?> clazz = null;
 427                 try {
 428                         clazz = Class.forName(type);
 429                 } catch (ClassNotFoundException e) {
 430                         int pos = type.length();
 431                         pos = type.lastIndexOf(".", pos);
 432                         if (pos >= 0) {
 433                                 String parentType = type.substring(0, pos);
 434                                 String nestedType = type.substring(pos + 1);
 435                                 Class<?> javaParent = null;
 436                                 try {
 437                                         javaParent = getClass(parentType);
 438                                         parentType = javaParent.getName();
 439                                         clazz = Class.forName(parentType + "$" + nestedType);
 440                                 } catch (Exception ee) {
 441                                 }
 442
 443                                 if (javaParent == null) {
 444                                         throw new NoSuchMethodException(
 445                                                         "Class not found: "
 446                                                                         + type
 447                                                                         + " (the enclosing class cannot be created: maybe it doesn't have an empty constructor?)");
 448                                 }
 449                         }
 450                 }
 451
 452                 if (clazz == null) {
 453                         throw new ClassNotFoundException("Class not found: " + type);
 454                 }
 455
 456                 return clazz;
 457         }
 458
 459         @SuppressWarnings({ "unchecked", "rawtypes" })
 460         private static Enum<?> decodeEnum(String escaped) {
 461                 // escaped: be.xxx.EnumType.VALUE;
 462                 int pos = escaped.lastIndexOf(".");
 463                 String type = escaped.substring(0, pos);
 464                 String name = escaped.substring(pos + 1, escaped.length() - 1);
 465
 466                 try {
 467                         return Enum.valueOf((Class<Enum>) getClass(type), name);
 468                 } catch (Exception e) {
 469                         throw new UnknownFormatConversionException("Unknown enum: <" + type
 470                                         + "> " + name);
 471                 }
 472         }
 473
 474         // aa bb -> "aa\tbb"
 475         private static void encodeString(StringBuilder builder, String raw) {
 476                 builder.append('\"');
 477                 for (char car : raw.toCharArray()) {
 478                         switch (car) {
 479                         case '\\':
 480                                 builder.append("\\\\");
 481                                 break;
 482                         case '\r':
 483                                 builder.append("\\r");
 484                                 break;
 485                         case '\n':
 486                                 builder.append("\\n");
 487                                 break;
 488                         case '"':
 489                                 builder.append("\\\"");
 490                                 break;
 491                         default:
 492                                 builder.append(car);
 493                                 break;
 494                         }
 495                 }
 496                 builder.append('\"');
 497         }
 498
 499         // "aa\tbb" -> aa bb
 500         private static String decodeString(String escaped) {
 501                 StringBuilder builder = new StringBuilder();
 502
 503                 boolean escaping = false;
 504                 for (char car : escaped.toCharArray()) {
 505                         if (!escaping) {
 506                                 if (car == '\\') {
 507                                         escaping = true;
 508                                 } else {
 509                                         builder.append(car);
 510                                 }
 511                         } else {
 512                                 switch (car) {
 513                                 case '\\':
 514                                         builder.append('\\');
 515                                         break;
 516                                 case 'r':
 517                                         builder.append('\r');
 518                                         break;
 519                                 case 'n':
 520                                         builder.append('\n');
 521                                         break;
 522                                 case '"':
 523                                         builder.append('"');
 524                                         break;
 525                                 }
 526                                 escaping = false;
 527                         }
 528                 }
 529
 530                 return builder.substring(1, builder.length() - 1).toString();
 531         }
 532 }