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