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

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