Struct 4 Java

gistfile1.txt

public class Struct {
  @Retention(RetentionPolicy.RUNTIME)
  @Target(ElementType.FIELD)
  public @interface Unsigned {
  }

  public void encode(ByteBuffer buffer) {
    for (Field field : this.getClass().getDeclaredFields()) {
      try {
        Object value = field.get(this);
        boolean signed = field.getAnnotation(Unsigned.class) != null;

        if (value instanceof Byte b) buffer.put(b);
        else if (value instanceof byte[] b) buffer.put(b);
        else if (value instanceof Boolean b) buffer.put((byte) (b ? 0x01 : 0x00));
        else if (value instanceof Short s && !signed) buffer.putShort(s);
        else if (value instanceof Short s) buffer.put(s.byteValue());
        else if (value instanceof Integer i && !signed) buffer.putInt(i);
        else if (value instanceof Integer i) buffer.putShort(i.shortValue());
        else if (value instanceof Long l && !signed) buffer.putLong(l);
        else if (value instanceof Long l) buffer.putInt(l.intValue());
        else if (value instanceof Float f) buffer.putFloat(f);
        else if (value instanceof Double d) buffer.putDouble(d);
        else if (value instanceof Character c) buffer.putChar(c);
        else if (value instanceof Struct s) s.encode(buffer);
        else throw new IllegalArgumentException();
      } catch (IllegalAccessException e) {
        throw new RuntimeException(e);
      }
    }
  }

  public void decode(ByteBuffer buffer) {
    for (Field field : this.getClass().getDeclaredFields()) {
      try {
        Object value = field.get(this);
        boolean signed = field.getAnnotation(Unsigned.class) != null;

        if (value instanceof Byte b) field.set(this, buffer.get(b));
        else if (value instanceof byte[] b) buffer.get(b);
        else if (value instanceof Boolean b) field.set(this, buffer.get() != 0 ? true : false);
        else if (value instanceof Short && !signed) field.set(this, buffer.getShort());
        else if (value instanceof Short) field.set(this, (short)Byte.toUnsignedInt(buffer.get()));
        else if (value instanceof Integer && !signed) field.set(this, buffer.getInt());
        else if (value instanceof Integer) field.set(this, Short.toUnsignedInt(buffer.getShort()));
        else if (value instanceof Long && !signed) field.set(this, buffer.getLong());
        else if (value instanceof Long) field.set(this, Integer.toUnsignedLong(buffer.getInt()));
        else if (value instanceof Float) field.set(this, buffer.getFloat());
        else if (value instanceof Double) field.set(this, buffer.getDouble());
        else if (value instanceof Character) field.set(this, buffer.getChar());
        else if (value instanceof Struct s) s.decode(buffer);
        else throw new IllegalArgumentException();
      } catch (IllegalAccessException e) {
        throw new RuntimeException(e);
      }
    }
  }

  @Override
  public String toString() {
    return ToStringBuilder.reflectionToString(this, ToStringStyle.JSON_STYLE);
  }
}