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

   1 package be.nikiroo.utils.serial;
   2
   3 import java.io.NotSerializableException;
   4 import java.lang.reflect.Array;
   5 import java.lang.reflect.Constructor;
   6 import java.lang.reflect.Field;
   7 import java.util.ArrayList;
   8 import java.util.HashMap;
   9 import java.util.Map;
  10 import java.util.UnknownFormatConversionException;
  11
  12 /**
  13  * Small class to help with serialisation.
  14  * <p>
  15  * Note that we do not support inner classes (but we do support nested classes)
  16  * and all objects require an empty constructor to be deserialised.
  17  *
  18  * @author niki
  19  */
  20 public class SerialUtils {
  21         private static Map<String, CustomSerializer> customTypes;
  22
  23         static {
  24                 customTypes = new HashMap<String, CustomSerializer>();
  25                 // TODO: add "default" custom serialisers if any (Bitmap?)
  26
  27                 // Array types:
  28                 customTypes.put("[]", new CustomSerializer() {
  29                         @Override
  30                         protected String toString(Object value) {
  31                                 String type = value.getClass().getCanonicalName();
  32                                 type = type.substring(0, type.length() - 2); // remove the []
  33
  34                                 StringBuilder builder = new StringBuilder();
  35                                 builder.append(type).append("\n");
  36                                 try {
  37                                         for (int i = 0; true; i++) {
  38                                                 Object item = Array.get(value, i);
  39                                                 // encode it normally if direct value
  40                                                 if (!SerialUtils.encode(builder, item)) {
  41                                                         try {
  42                                                                 // use ZIP: if not
  43                                                                 builder.append(new Exporter().append(item)
  44                                                                                 .toString(true));
  45                                                         } catch (NotSerializableException e) {
  46                                                                 throw new UnknownFormatConversionException(e
  47                                                                                 .getMessage());
  48                                                         }
  49                                                 }
  50                                                 builder.append("\n");
  51                                         }
  52                                 } catch (ArrayIndexOutOfBoundsException e) {
  53                                         // Done.
  54                                 }
  55
  56                                 return builder.toString();
  57                         }
  58
  59                         @Override
  60                         protected String getType() {
  61                                 return "[]";
  62                         }
  63
  64                         @Override
  65                         protected Object fromString(String content) {
  66                                 String[] tab = content.split("\n");
  67
  68                                 try {
  69                                         Object array = Array.newInstance(
  70                                                         SerialUtils.getClass(tab[0]), tab.length - 1);
  71                                         for (int i = 1; i < tab.length; i++) {
  72                                                 Object value = new Importer().read(tab[i]).getValue();
  73                                                 Array.set(array, i - 1, value);
  74                                         }
  75
  76                                         return array;
  77                                 } catch (Exception e) {
  78                                         throw new UnknownFormatConversionException(e.getMessage());
  79                                 }
  80                         }
  81                 });
  82         }
  83
  84         /**
  85          * Create an empty object of the given type.
  86          *
  87          * @param type
  88          *            the object type (its class name)
  89          *
  90          * @return the new object
  91          *
  92          * @throws ClassNotFoundException
  93          *             if the class cannot be found
  94          * @throws NoSuchMethodException
  95          *             if the given class is not compatible with this code
  96          */
  97         public static Object createObject(String type)
  98                         throws ClassNotFoundException, NoSuchMethodException {
  99
 100                 try {
 101                         Class<?> clazz = getClass(type);
 102                         String className = clazz.getName();
 103                         Object[] args = null;
 104                         Constructor<?> ctor = null;
 105                         if (className.contains("$")) {
 106                                 Object javaParent = createObject(className.substring(0,
 107                                                 className.lastIndexOf('$')));
 108                                 args = new Object[] { javaParent };
 109                                 ctor = clazz.getDeclaredConstructor(new Class[] { javaParent
 110                                                 .getClass() });
 111                         } else {
 112                                 args = new Object[] {};
 113                                 ctor = clazz.getDeclaredConstructor();
 114                         }
 115
 116                         ctor.setAccessible(true);
 117                         return ctor.newInstance(args);
 118                 } catch (ClassNotFoundException e) {
 119                         throw e;
 120                 } catch (NoSuchMethodException e) {
 121                         throw e;
 122                 } catch (Exception e) {
 123                         throw new NoSuchMethodException("Cannot instantiate: " + type);
 124                 }
 125         }
 126
 127         /**
 128          * Insert a custom serialiser that will take precedence over the default one
 129          * or the target class.
 130          *
 131          * @param serializer
 132          *            the custom serialiser
 133          */
 134         static public void addCustomSerializer(CustomSerializer serializer) {
 135                 customTypes.put(serializer.getType(), serializer);
 136         }
 137
 138         /**
 139          * Serialise the given object into this {@link StringBuilder}.
 140          * <p>
 141          * <b>Important: </b>If the operation fails (with a
 142          * {@link NotSerializableException}), the {@link StringBuilder} will be
 143          * corrupted (will contain bad, most probably not importable data).
 144          *
 145          * @param builder
 146          *            the output {@link StringBuilder} to serialise to
 147          * @param o
 148          *            the object to serialise
 149          * @param map
 150          *            the map of already serialised objects (if the given object or
 151          *            one of its descendant is already present in it, only an ID
 152          *            will be serialised)
 153          *
 154          * @throws NotSerializableException
 155          *             if the object cannot be serialised (in this case, the
 156          *             {@link StringBuilder} can contain bad, most probably not
 157          *             importable data)
 158          */
 159         static void append(StringBuilder builder, Object o, Map<Integer, Object> map)
 160                         throws NotSerializableException {
 161
 162                 Field[] fields = new Field[] {};
 163                 String type = "";
 164                 String id = "NULL";
 165
 166                 if (o != null) {
 167                         int hash = System.identityHashCode(o);
 168                         fields = o.getClass().getDeclaredFields();
 169                         type = o.getClass().getCanonicalName();
 170                         if (type == null) {
 171                                 throw new NotSerializableException(
 172                                                 String.format(
 173                                                                 "Cannot find the class for this object: %s (it could be an inner class, which is not supported)",
 174                                                                 o));
 175                         }
 176                         id = Integer.toString(hash);
 177                         if (map.containsKey(hash)) {
 178                                 fields = new Field[] {};
 179                         } else {
 180                                 map.put(hash, o);
 181                         }
 182                 }
 183
 184                 builder.append("{\nREF ").append(type).append("@").append(id)
 185                                 .append(":");
 186                 if (!encode(builder, o)) { // check if direct value
 187                         try {
 188                                 for (Field field : fields) {
 189                                         field.setAccessible(true);
 190
 191                                         if (field.getName().startsWith("this$")) {
 192                                                 // Do not keep this links of nested classes
 193                                                 continue;
 194                                         }
 195
 196                                         builder.append("\n");
 197                                         builder.append(field.getName());
 198                                         builder.append(":");
 199                                         Object value;
 200
 201                                         value = field.get(o);
 202
 203                                         if (!encode(builder, value)) {
 204                                                 builder.append("\n");
 205                                                 append(builder, value, map);
 206                                         }
 207                                 }
 208                         } catch (IllegalArgumentException e) {
 209                                 e.printStackTrace(); // should not happen (see
 210                                                                                 // setAccessible)
 211                         } catch (IllegalAccessException e) {
 212                                 e.printStackTrace(); // should not happen (see
 213                                                                                 // setAccessible)
 214                         }
 215                 }
 216                 builder.append("\n}");
 217         }
 218
 219         // return true if encoded (supported)
 220         static boolean encode(StringBuilder builder, Object value) {
 221                 if (value == null) {
 222                         builder.append("NULL");
 223                 } else if (value.getClass().getCanonicalName().endsWith("[]")) {
 224                         customTypes.get("[]").encode(builder, value);
 225                 } else if (customTypes.containsKey(value.getClass().getCanonicalName())) {
 226                         customTypes.get(value.getClass().getCanonicalName())//
 227                                         .encode(builder, value);
 228                 } else if (value instanceof String) {
 229                         encodeString(builder, (String) value);
 230                 } else if (value instanceof Boolean) {
 231                         builder.append(value);
 232                 } else if (value instanceof Byte) {
 233                         builder.append(value).append('b');
 234                 } else if (value instanceof Character) {
 235                         encodeString(builder, "" + value);
 236                         builder.append('c');
 237                 } else if (value instanceof Short) {
 238                         builder.append(value).append('s');
 239                 } else if (value instanceof Integer) {
 240                         builder.append(value);
 241                 } else if (value instanceof Long) {
 242                         builder.append(value).append('L');
 243                 } else if (value instanceof Float) {
 244                         builder.append(value).append('F');
 245                 } else if (value instanceof Double) {
 246                         builder.append(value).append('d');
 247                 } else {
 248                         return false;
 249                 }
 250
 251                 return true;
 252         }
 253
 254         static Object decode(String encodedValue) {
 255                 String cut = "";
 256                 if (encodedValue.length() > 1) {
 257                         cut = encodedValue.substring(0, encodedValue.length() - 1);
 258                 }
 259
 260                 if (CustomSerializer.isCustom(encodedValue)) {
 261                         // custom:TYPE_NAME:"content is String-encoded"
 262                         String type = CustomSerializer.typeOf(encodedValue);
 263                         if (customTypes.containsKey(type)) {
 264                                 return customTypes.get(type).decode(encodedValue);
 265                         } else {
 266                                 throw new UnknownFormatConversionException(
 267                                                 "Unknown custom type: " + type);
 268                         }
 269                 } else if (encodedValue.equals("NULL") || encodedValue.equals("null")) {
 270                         return null;
 271                 } else if (encodedValue.endsWith("\"")) {
 272                         return decodeString(encodedValue);
 273                 } else if (encodedValue.equals("true")) {
 274                         return true;
 275                 } else if (encodedValue.equals("false")) {
 276                         return false;
 277                 } else if (encodedValue.endsWith("b")) {
 278                         return Byte.parseByte(cut);
 279                 } else if (encodedValue.endsWith("c")) {
 280                         return decodeString(cut).charAt(0);
 281                 } else if (encodedValue.endsWith("s")) {
 282                         return Short.parseShort(cut);
 283                 } else if (encodedValue.endsWith("L")) {
 284                         return Long.parseLong(cut);
 285                 } else if (encodedValue.endsWith("F")) {
 286                         return Float.parseFloat(cut);
 287                 } else if (encodedValue.endsWith("d")) {
 288                         return Double.parseDouble(cut);
 289                 } else {
 290                         return Integer.parseInt(encodedValue);
 291                 }
 292         }
 293
 294         /**
 295          * Return the corresponding class or throw an {@link Exception} if it
 296          * cannot.
 297          *
 298          * @param type
 299          *            the class name to look for
 300          *
 301          * @return the class (will never be NULL)
 302          *
 303          * @throws ClassNotFoundException
 304          *             if the class cannot be found
 305          * @throws NoSuchMethodException
 306          *             if the class cannot be created (usually because it or its
 307          *             enclosing class doesn't have an empty constructor)
 308          */
 309         static private Class<?> getClass(String type)
 310                         throws ClassNotFoundException, NoSuchMethodException {
 311                 Class<?> clazz = null;
 312                 try {
 313                         clazz = Class.forName(type);
 314                 } catch (ClassNotFoundException e) {
 315                         int pos = type.length();
 316                         pos = type.lastIndexOf(".", pos);
 317                         if (pos >= 0) {
 318                                 String parentType = type.substring(0, pos);
 319                                 String nestedType = type.substring(pos + 1);
 320                                 Class<?> javaParent = null;
 321                                 try {
 322                                         javaParent = getClass(parentType);
 323                                         parentType = javaParent.getName();
 324                                         clazz = Class.forName(parentType + "$" + nestedType);
 325                                 } catch (Exception ee) {
 326                                 }
 327
 328                                 if (javaParent == null) {
 329                                         throw new NoSuchMethodException(
 330                                                         "Class not found: "
 331                                                                         + type
 332                                                                         + " (the enclosing class cannot be created: maybe it doesn't have an empty constructor?)");
 333                                 }
 334                         }
 335                 }
 336
 337                 if (clazz == null) {
 338                         throw new ClassNotFoundException("Class not found: " + type);
 339                 }
 340
 341                 return clazz;
 342         }
 343
 344         // aa bb -> "aa\tbb"
 345         private static void encodeString(StringBuilder builder, String raw) {
 346                 builder.append('\"');
 347                 for (char car : raw.toCharArray()) {
 348                         switch (car) {
 349                         case '\\':
 350                                 builder.append("\\\\");
 351                                 break;
 352                         case '\r':
 353                                 builder.append("\\r");
 354                                 break;
 355                         case '\n':
 356                                 builder.append("\\n");
 357                                 break;
 358                         case '"':
 359                                 builder.append("\\\"");
 360                                 break;
 361                         default:
 362                                 builder.append(car);
 363                                 break;
 364                         }
 365                 }
 366                 builder.append('\"');
 367         }
 368
 369         // "aa\tbb" -> aa bb
 370         private static String decodeString(String escaped) {
 371                 StringBuilder builder = new StringBuilder();
 372
 373                 boolean escaping = false;
 374                 for (char car : escaped.toCharArray()) {
 375                         if (!escaping) {
 376                                 if (car == '\\') {
 377                                         escaping = true;
 378                                 } else {
 379                                         builder.append(car);
 380                                 }
 381                         } else {
 382                                 switch (car) {
 383                                 case '\\':
 384                                         builder.append('\\');
 385                                         break;
 386                                 case 'r':
 387                                         builder.append('\r');
 388                                         break;
 389                                 case 'n':
 390                                         builder.append('\n');
 391                                         break;
 392                                 case '"':
 393                                         builder.append('"');
 394                                         break;
 395                                 }
 396                                 escaping = false;
 397                         }
 398                 }
 399
 400                 return builder.substring(1, builder.length() - 1).toString();
 401         }
 402 }