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