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.ArrayList;
  11 import java.util.HashMap;
  12 import java.util.List;
  13 import java.util.Map;
  14 import java.util.UnknownFormatConversionException;
  15
  16 import be.nikiroo.utils.Image;
  17
  18 /**
  19  * Small class to help with serialisation.
  20  * <p>
  21  * Note that we do not support inner classes (but we do support nested classes)
  22  * and all objects require an empty constructor to be deserialised.
  23  * <p>
  24  * It is possible to add support to custom types (both the encoder and the
  25  * decoder will require the custom classes) -- see {@link CustomSerializer}.
  26  * <p>
  27  * Default supported types are:
  28  * <ul>
  29  * <li>NULL (as a null value)</li>
  30  * <li>String</li>
  31  * <li>Boolean</li>
  32  * <li>Byte</li>
  33  * <li>Character</li>
  34  * <li>Short</li>
  35  * <li>Long</li>
  36  * <li>Float</li>
  37  * <li>Double</li>
  38  * <li>Integer</li>
  39  * <li>Enum (any enum whose name and value is known by the caller)</li>
  40  * <li>java.awt.image.BufferedImage (as a {@link CustomSerializer})</li>
  41  * <li>An array of the above (as a {@link CustomSerializer})</li>
  42  * <li>URL</li>
  43  * </ul>
  44  *
  45  * @author niki
  46  */
  47 public class SerialUtils {
  48         private static Map<String, CustomSerializer> customTypes;
  49
  50         static {
  51                 customTypes = new HashMap<String, CustomSerializer>();
  52
  53                 // Array types:
  54                 customTypes.put("[]", new CustomSerializer() {
  55                         @Override
  56                         protected String toString(Object value) {
  57                                 String type = value.getClass().getCanonicalName();
  58                                 type = type.substring(0, type.length() - 2); // remove the []
  59
  60                                 StringBuilder builder = new StringBuilder();
  61                                 builder.append(type).append("\n");
  62                                 try {
  63                                         for (int i = 0; true; i++) {
  64                                                 Object item = Array.get(value, i);
  65                                                 // encode it normally if direct value
  66                                                 if (!SerialUtils.encode(builder, item)) {
  67                                                         try {
  68                                                                 // use ZIP: if not
  69                                                                 builder.append(new Exporter().append(item)
  70                                                                                 .toString(true));
  71                                                         } catch (NotSerializableException e) {
  72                                                                 throw new UnknownFormatConversionException(e
  73                                                                                 .getMessage());
  74                                                         }
  75                                                 }
  76                                                 builder.append("\n");
  77                                         }
  78                                 } catch (ArrayIndexOutOfBoundsException e) {
  79                                         // Done.
  80                                 }
  81
  82                                 return builder.toString();
  83                         }
  84
  85                         @Override
  86                         protected String getType() {
  87                                 return "[]";
  88                         }
  89
  90                         @Override
  91                         protected Object fromString(String content) throws IOException {
  92                                 String[] tab = content.split("\n");
  93
  94                                 try {
  95                                         Object array = Array.newInstance(
  96                                                         SerialUtils.getClass(tab[0]), tab.length - 1);
  97                                         for (int i = 1; i < tab.length; i++) {
  98                                                 Object value = new Importer().read(tab[i]).getValue();
  99                                                 Array.set(array, i - 1, value);
 100                                         }
 101
 102                                         return array;
 103                                 } catch (Exception e) {
 104                                         if (e instanceof IOException) {
 105                                                 throw (IOException) e;
 106                                         }
 107                                         throw new IOException(e.getMessage());
 108                                 }
 109                         }
 110                 });
 111
 112                 // URL:
 113                 customTypes.put("java.net.URL", new CustomSerializer() {
 114                         @Override
 115                         protected String toString(Object value) {
 116                                 if (value != null) {
 117                                         return ((URL) value).toString();
 118                                 }
 119                                 return null;
 120                         }
 121
 122                         @Override
 123                         protected Object fromString(String content) throws IOException {
 124                                 if (content != null) {
 125                                         return new URL(content);
 126                                 }
 127                                 return null;
 128                         }
 129
 130                         @Override
 131                         protected String getType() {
 132                                 return "java.net.URL";
 133                         }
 134                 });
 135
 136                 // Images (this is currently the only supported image type by default)
 137                 customTypes.put("be.nikiroo.utils.Image", new CustomSerializer() {
 138                         @Override
 139                         protected String toString(Object value) {
 140                                 return ((Image) value).toBase64();
 141                         }
 142
 143                         @Override
 144                         protected String getType() {
 145                                 return "be.nikiroo.utils.Image";
 146                         }
 147
 148                         @Override
 149                         protected Object fromString(String content) {
 150                                 try {
 151                                         return new Image(content);
 152                                 } catch (IOException e) {
 153                                         throw new UnknownFormatConversionException(e.getMessage());
 154                                 }
 155                         }
 156                 });
 157         }
 158
 159         /**
 160          * Create an empty object of the given type.
 161          *
 162          * @param type
 163          *            the object type (its class name)
 164          *
 165          * @return the new object
 166          *
 167          * @throws ClassNotFoundException
 168          *             if the class cannot be found
 169          * @throws NoSuchMethodException
 170          *             if the given class is not compatible with this code
 171          */
 172         public static Object createObject(String type)
 173                         throws ClassNotFoundException, NoSuchMethodException {
 174
 175                 String desc = null;
 176
 177                 try {
 178                         Class<?> clazz = getClass(type);
 179                         String className = clazz.getName();
 180                         List<Object> args = new ArrayList<Object>();
 181                         List<Class<?>> classes = new ArrayList<Class<?>>();
 182                         Constructor<?> ctor = null;
 183                         if (className.contains("$")) {
 184                                 for (String parentName = className.substring(0,
 185                                                 className.lastIndexOf('$'));; parentName = parentName
 186                                                 .substring(0, parentName.lastIndexOf('$'))) {
 187                                         Object parent = createObject(parentName);
 188                                         args.add(parent);
 189                                         classes.add(parent.getClass());
 190
 191                                         if (!parentName.contains("$")) {
 192                                                 break;
 193                                         }
 194                                 }
 195
 196                                 // Better error description in case there is no empty
 197                                 // constructor:
 198                                 desc = "";
 199                                 String end = "";
 200                                 for (Class<?> parent = clazz; parent != null
 201                                                 && !parent.equals(Object.class); parent = parent
 202                                                 .getSuperclass()) {
 203                                         if (!desc.isEmpty()) {
 204                                                 desc += " [:";
 205                                                 end += "]";
 206                                         }
 207                                         desc += parent;
 208                                 }
 209                                 desc += end;
 210                                 //
 211
 212                                 ctor = clazz.getDeclaredConstructor(classes
 213                                                 .toArray(new Class[] {}));
 214                                 desc = null;
 215                         } else {
 216                                 ctor = clazz.getDeclaredConstructor();
 217                         }
 218
 219                         ctor.setAccessible(true);
 220                         return ctor.newInstance(args.toArray());
 221                 } catch (ClassNotFoundException e) {
 222                         throw e;
 223                 } catch (NoSuchMethodException e) {
 224                         if (desc != null) {
 225                                 throw new NoSuchMethodException("Empty constructor not found: "
 226                                                 + desc);
 227                         }
 228                         throw e;
 229                 } catch (Exception e) {
 230                         throw new NoSuchMethodException("Cannot instantiate: " + type);
 231                 }
 232         }
 233
 234         /**
 235          * Insert a custom serialiser that will take precedence over the default one
 236          * or the target class.
 237          *
 238          * @param serializer
 239          *            the custom serialiser
 240          */
 241         static public void addCustomSerializer(CustomSerializer serializer) {
 242                 customTypes.put(serializer.getType(), serializer);
 243         }
 244
 245         /**
 246          * Serialise the given object into this {@link StringBuilder}.
 247          * <p>
 248          * <b>Important: </b>If the operation fails (with a
 249          * {@link NotSerializableException}), the {@link StringBuilder} will be
 250          * corrupted (will contain bad, most probably not importable data).
 251          *
 252          * @param builder
 253          *            the output {@link StringBuilder} to serialise to
 254          * @param o
 255          *            the object to serialise
 256          * @param map
 257          *            the map of already serialised objects (if the given object or
 258          *            one of its descendant is already present in it, only an ID
 259          *            will be serialised)
 260          *
 261          * @throws NotSerializableException
 262          *             if the object cannot be serialised (in this case, the
 263          *             {@link StringBuilder} can contain bad, most probably not
 264          *             importable data)
 265          */
 266         static void append(StringBuilder builder, Object o, Map<Integer, Object> map)
 267                         throws NotSerializableException {
 268
 269                 Field[] fields = new Field[] {};
 270                 String type = "";
 271                 String id = "NULL";
 272
 273                 if (o != null) {
 274                         int hash = System.identityHashCode(o);
 275                         fields = o.getClass().getDeclaredFields();
 276                         type = o.getClass().getCanonicalName();
 277                         if (type == null) {
 278                                 // Anonymous inner classes support
 279                                 type = o.getClass().getName();
 280                         }
 281                         id = Integer.toString(hash);
 282                         if (map.containsKey(hash)) {
 283                                 fields = new Field[] {};
 284                         } else {
 285                                 map.put(hash, o);
 286                         }
 287                 }
 288
 289                 builder.append("{\nREF ").append(type).append("@").append(id)
 290                                 .append(":");
 291                 if (!encode(builder, o)) { // check if direct value
 292                         try {
 293                                 for (Field field : fields) {
 294                                         field.setAccessible(true);
 295
 296                                         if (field.getName().startsWith("this$")
 297                                                         || field.isSynthetic()
 298                                                         || (field.getModifiers() & Modifier.STATIC) == Modifier.STATIC) {
 299                                                 // Do not keep this links of nested classes
 300                                                 // Do not keep synthetic fields
 301                                                 // Do not keep final fields
 302                                                 continue;
 303                                         }
 304
 305                                         builder.append("\n");
 306                                         builder.append(field.getName());
 307                                         builder.append(":");
 308                                         Object value;
 309
 310                                         value = field.get(o);
 311
 312                                         if (!encode(builder, value)) {
 313                                                 builder.append("\n");
 314                                                 append(builder, value, map);
 315                                         }
 316                                 }
 317                         } catch (IllegalArgumentException e) {
 318                                 e.printStackTrace(); // should not happen (see
 319                                                                                 // setAccessible)
 320                         } catch (IllegalAccessException e) {
 321                                 e.printStackTrace(); // should not happen (see
 322                                                                                 // setAccessible)
 323                         }
 324                 }
 325                 builder.append("\n}");
 326         }
 327
 328         /**
 329          * Encode the object into the given builder if possible and if supported.
 330          * <p>
 331          * A supported object in this context means an object we can directly
 332          * encode, like an Integer or a String. Custom objects and arrays are also
 333          * considered supported, but <b>compound objects are not supported here</b>.
 334          * <p>
 335          * For compound objects, you should use {@link Exporter}.
 336          *
 337          * @param builder
 338          *            the builder to append to
 339          * @param value
 340          *            the object to encode (can be NULL, which will be encoded)
 341          *
 342          * @return TRUE if success, FALSE if not (the content of the builder won't
 343          *         be changed in case of failure)
 344          */
 345         static boolean encode(StringBuilder builder, Object value) {
 346                 if (value == null) {
 347                         builder.append("NULL");
 348                 } else if (value.getClass().getSimpleName().endsWith("[]")) {
 349                         // Simple name does support [] suffix and do not return NULL for
 350                         // inner anonymous classes
 351                         return customTypes.get("[]").encode(builder, value);
 352                 } else if (customTypes.containsKey(value.getClass().getCanonicalName())) {
 353                         return customTypes.get(value.getClass().getCanonicalName())//
 354                                         .encode(builder, value);
 355                 } else if (value instanceof String) {
 356                         encodeString(builder, (String) value);
 357                 } else if (value instanceof Boolean) {
 358                         builder.append(value);
 359                 } else if (value instanceof Byte) {
 360                         builder.append(value).append('b');
 361                 } else if (value instanceof Character) {
 362                         encodeString(builder, "" + value);
 363                         builder.append('c');
 364                 } else if (value instanceof Short) {
 365                         builder.append(value).append('s');
 366                 } else if (value instanceof Integer) {
 367                         builder.append(value);
 368                 } else if (value instanceof Long) {
 369                         builder.append(value).append('L');
 370                 } else if (value instanceof Float) {
 371                         builder.append(value).append('F');
 372                 } else if (value instanceof Double) {
 373                         builder.append(value).append('d');
 374                 } else if (value instanceof Enum) {
 375                         String type = value.getClass().getCanonicalName();
 376                         builder.append(type).append(".").append(((Enum<?>) value).name())
 377                                         .append(";");
 378                 } else {
 379                         return false;
 380                 }
 381
 382                 return true;
 383         }
 384
 385         /**
 386          * Decode the data into an equivalent supported source object.
 387          * <p>
 388          * A supported object in this context means an object we can directly
 389          * encode, like an Integer or a String. Custom objects and arrays are also
 390          * considered supported, but <b>compound objects are not supported here</b>.
 391          * <p>
 392          * For compound objects, you should use {@link Importer}.
 393          *
 394          * @param encodedValue
 395          *            the encoded data, cannot be NULL
 396          *
 397          * @return the object (can be NULL for NULL encoded values)
 398          *
 399          * @throws IOException
 400          *             if the content cannot be converted
 401          */
 402         static Object decode(String encodedValue) throws IOException {
 403                 try {
 404                         String cut = "";
 405                         if (encodedValue.length() > 1) {
 406                                 cut = encodedValue.substring(0, encodedValue.length() - 1);
 407                         }
 408
 409                         if (CustomSerializer.isCustom(encodedValue)) {
 410                                 // custom:TYPE_NAME:"content is String-encoded"
 411                                 String type = CustomSerializer.typeOf(encodedValue);
 412                                 if (customTypes.containsKey(type)) {
 413                                         return customTypes.get(type).decode(encodedValue);
 414                                 }
 415                                 throw new IOException("Unknown custom type: " + type);
 416                         } else if (encodedValue.equals("NULL")
 417                                         || encodedValue.equals("null")) {
 418                                 return null;
 419                         } else if (encodedValue.endsWith("\"")) {
 420                                 return decodeString(encodedValue);
 421                         } else if (encodedValue.equals("true")) {
 422                                 return true;
 423                         } else if (encodedValue.equals("false")) {
 424                                 return false;
 425                         } else if (encodedValue.endsWith("b")) {
 426                                 return Byte.parseByte(cut);
 427                         } else if (encodedValue.endsWith("c")) {
 428                                 return decodeString(cut).charAt(0);
 429                         } else if (encodedValue.endsWith("s")) {
 430                                 return Short.parseShort(cut);
 431                         } else if (encodedValue.endsWith("L")) {
 432                                 return Long.parseLong(cut);
 433                         } else if (encodedValue.endsWith("F")) {
 434                                 return Float.parseFloat(cut);
 435                         } else if (encodedValue.endsWith("d")) {
 436                                 return Double.parseDouble(cut);
 437                         } else if (encodedValue.endsWith(";")) {
 438                                 return decodeEnum(encodedValue);
 439                         } else {
 440                                 return Integer.parseInt(encodedValue);
 441                         }
 442                 } catch (Exception e) {
 443                         if (e instanceof IOException) {
 444                                 throw (IOException) e;
 445                         }
 446                         throw new IOException(e.getMessage());
 447                 }
 448         }
 449
 450         /**
 451          * Return the corresponding class or throw an {@link Exception} if it
 452          * cannot.
 453          *
 454          * @param type
 455          *            the class name to look for
 456          *
 457          * @return the class (will never be NULL)
 458          *
 459          * @throws ClassNotFoundException
 460          *             if the class cannot be found
 461          * @throws NoSuchMethodException
 462          *             if the class cannot be created (usually because it or its
 463          *             enclosing class doesn't have an empty constructor)
 464          */
 465         static private Class<?> getClass(String type)
 466                         throws ClassNotFoundException, NoSuchMethodException {
 467                 Class<?> clazz = null;
 468                 try {
 469                         clazz = Class.forName(type);
 470                 } catch (ClassNotFoundException e) {
 471                         int pos = type.length();
 472                         pos = type.lastIndexOf(".", pos);
 473                         if (pos >= 0) {
 474                                 String parentType = type.substring(0, pos);
 475                                 String nestedType = type.substring(pos + 1);
 476                                 Class<?> javaParent = null;
 477                                 try {
 478                                         javaParent = getClass(parentType);
 479                                         parentType = javaParent.getName();
 480                                         clazz = Class.forName(parentType + "$" + nestedType);
 481                                 } catch (Exception ee) {
 482                                 }
 483
 484                                 if (javaParent == null) {
 485                                         throw new NoSuchMethodException(
 486                                                         "Class not found: "
 487                                                                         + type
 488                                                                         + " (the enclosing class cannot be created: maybe it doesn't have an empty constructor?)");
 489                                 }
 490                         }
 491                 }
 492
 493                 if (clazz == null) {
 494                         throw new ClassNotFoundException("Class not found: " + type);
 495                 }
 496
 497                 return clazz;
 498         }
 499
 500         @SuppressWarnings({ "unchecked", "rawtypes" })
 501         private static Enum<?> decodeEnum(String escaped) {
 502                 // escaped: be.xxx.EnumType.VALUE;
 503                 int pos = escaped.lastIndexOf(".");
 504                 String type = escaped.substring(0, pos);
 505                 String name = escaped.substring(pos + 1, escaped.length() - 1);
 506
 507                 try {
 508                         return Enum.valueOf((Class<Enum>) getClass(type), name);
 509                 } catch (Exception e) {
 510                         throw new UnknownFormatConversionException("Unknown enum: <" + type
 511                                         + "> " + name);
 512                 }
 513         }
 514
 515         // aa bb -> "aa\tbb"
 516         private static void encodeString(StringBuilder builder, String raw) {
 517                 builder.append('\"');
 518                 for (char car : raw.toCharArray()) {
 519                         switch (car) {
 520                         case '\\':
 521                                 builder.append("\\\\");
 522                                 break;
 523                         case '\r':
 524                                 builder.append("\\r");
 525                                 break;
 526                         case '\n':
 527                                 builder.append("\\n");
 528                                 break;
 529                         case '"':
 530                                 builder.append("\\\"");
 531                                 break;
 532                         default:
 533                                 builder.append(car);
 534                                 break;
 535                         }
 536                 }
 537                 builder.append('\"');
 538         }
 539
 540         // "aa\tbb" -> aa bb
 541         private static String decodeString(String escaped) {
 542                 StringBuilder builder = new StringBuilder();
 543
 544                 boolean escaping = false;
 545                 for (char car : escaped.toCharArray()) {
 546                         if (!escaping) {
 547                                 if (car == '\\') {
 548                                         escaping = true;
 549                                 } else {
 550                                         builder.append(car);
 551                                 }
 552                         } else {
 553                                 switch (car) {
 554                                 case '\\':
 555                                         builder.append('\\');
 556                                         break;
 557                                 case 'r':
 558                                         builder.append('\r');
 559                                         break;
 560                                 case 'n':
 561                                         builder.append('\n');
 562                                         break;
 563                                 case '"':
 564                                         builder.append('"');
 565                                         break;
 566                                 }
 567                                 escaping = false;
 568                         }
 569                 }
 570
 571                 return builder.substring(1, builder.length() - 1);
 572         }
 573 }