예제 #1
0
  /** Write a {@link Writable}, {@link String}, primitive type, or an array of the preceding. */
  public static void writeObject(
      DataOutput out, Object instance, Class declaredClass, Configuration conf) throws IOException {

    if (instance == null) { // null
      instance = new NullInstance(declaredClass, conf);
      declaredClass = Writable.class;
    }

    UTF8.writeString(out, declaredClass.getName()); // always write declared

    if (declaredClass.isArray()) { // array
      int length = Array.getLength(instance);
      out.writeInt(length);
      for (int i = 0; i < length; i++) {
        writeObject(out, Array.get(instance, i), declaredClass.getComponentType(), conf);
      }

    } else if (declaredClass == String.class) { // String
      UTF8.writeString(out, (String) instance);

    } else if (declaredClass.isPrimitive()) { // primitive type

      if (declaredClass == Boolean.TYPE) { // boolean
        out.writeBoolean(((Boolean) instance).booleanValue());
      } else if (declaredClass == Character.TYPE) { // char
        out.writeChar(((Character) instance).charValue());
      } else if (declaredClass == Byte.TYPE) { // byte
        out.writeByte(((Byte) instance).byteValue());
      } else if (declaredClass == Short.TYPE) { // short
        out.writeShort(((Short) instance).shortValue());
      } else if (declaredClass == Integer.TYPE) { // int
        out.writeInt(((Integer) instance).intValue());
      } else if (declaredClass == Long.TYPE) { // long
        out.writeLong(((Long) instance).longValue());
      } else if (declaredClass == Float.TYPE) { // float
        out.writeFloat(((Float) instance).floatValue());
      } else if (declaredClass == Double.TYPE) { // double
        out.writeDouble(((Double) instance).doubleValue());
      } else if (declaredClass == Void.TYPE) { // void
      } else {
        throw new IllegalArgumentException("Not a primitive: " + declaredClass);
      }
    } else if (declaredClass.isEnum()) { // enum
      UTF8.writeString(out, ((Enum) instance).name());
    } else if (Writable.class.isAssignableFrom(declaredClass)) { // Writable
      UTF8.writeString(out, instance.getClass().getName());
      ((Writable) instance).write(out);

    } else {
      throw new IOException("Can't write: " + instance + " as " + declaredClass);
    }
  }
예제 #2
0
  /** Read a {@link Writable}, {@link String}, primitive type, or an array of the preceding. */
  @SuppressWarnings("unchecked")
  public static Object readObject(DataInput in, ObjectWritable objectWritable, Configuration conf)
      throws IOException {
    String className = UTF8.readString(in);
    Class<?> declaredClass = PRIMITIVE_NAMES.get(className);
    if (declaredClass == null) {
      declaredClass = loadClass(conf, className);
    }

    Object instance;

    if (declaredClass.isPrimitive()) { // primitive types

      if (declaredClass == Boolean.TYPE) { // boolean
        instance = Boolean.valueOf(in.readBoolean());
      } else if (declaredClass == Character.TYPE) { // char
        instance = Character.valueOf(in.readChar());
      } else if (declaredClass == Byte.TYPE) { // byte
        instance = Byte.valueOf(in.readByte());
      } else if (declaredClass == Short.TYPE) { // short
        instance = Short.valueOf(in.readShort());
      } else if (declaredClass == Integer.TYPE) { // int
        instance = Integer.valueOf(in.readInt());
      } else if (declaredClass == Long.TYPE) { // long
        instance = Long.valueOf(in.readLong());
      } else if (declaredClass == Float.TYPE) { // float
        instance = Float.valueOf(in.readFloat());
      } else if (declaredClass == Double.TYPE) { // double
        instance = Double.valueOf(in.readDouble());
      } else if (declaredClass == Void.TYPE) { // void
        instance = null;
      } else {
        throw new IllegalArgumentException("Not a primitive: " + declaredClass);
      }

    } else if (declaredClass.isArray()) { // array
      int length = in.readInt();
      instance = Array.newInstance(declaredClass.getComponentType(), length);
      for (int i = 0; i < length; i++) {
        Array.set(instance, i, readObject(in, conf));
      }

    } else if (declaredClass == String.class) { // String
      instance = UTF8.readString(in);
    } else if (declaredClass.isEnum()) { // enum
      instance = Enum.valueOf((Class<? extends Enum>) declaredClass, UTF8.readString(in));
    } else { // Writable
      Class instanceClass = null;
      String str = UTF8.readString(in);
      instanceClass = loadClass(conf, str);

      Writable writable = WritableFactories.newInstance(instanceClass, conf);
      writable.readFields(in);
      instance = writable;

      if (instanceClass == NullInstance.class) { // null
        declaredClass = ((NullInstance) instance).declaredClass;
        instance = null;
      }
    }

    if (objectWritable != null) { // store values
      objectWritable.declaredClass = declaredClass;
      objectWritable.instance = instance;
    }

    return instance;
  }