com.google.common.base.Utf8#encodedLength ( )源码实例Demo

@Nullable
private static String getSanitizedId(@Nonnull String id) {
    try {
        if (Utf8.encodedLength(id) > MAX_TR_ID_SIZE) {
            if (CharMatcher.ascii().matchesAllOf(id)) {
                // Most of the time, the string will be of ascii characters, so return a truncated ID based on length
                return id.substring(0, MAX_TR_ID_SIZE - 3) + "...";
            } else {
                // In theory, we could try and split the UTF-16 string and find a string that fits, but that
                // is fraught with peril, not the least of which because one might accidentally split a low
                // surrogate/high surrogate pair.
                return null;
            }
        } else {
            return id;
        }
    } catch (IllegalArgumentException e) {
        return null;
    }
}
 

/**
 * 计算字符串被UTF8编码后的字节数 via guava
 * 
 * @see Utf8#encodedLength(CharSequence)
 */
public static int utf8EncodedLength(@Nullable CharSequence sequence) {
	if (StringUtils.isEmpty(sequence)) {
		return 0;
	}
	return Utf8.encodedLength(sequence);
}
 

/**
 * 计算字符串被UTF8编码后的字节数 via guava
 * 
 * @see Utf8#encodedLength(CharSequence)
 */
public static int utf8EncodedLength(@Nullable CharSequence sequence) {
	if (StringUtils.isEmpty(sequence)) {
		return 0;
	}
	return Utf8.encodedLength(sequence);
}
 

/**
 * 计算字符串被UTF8编码后的字节数 via guava
 * 
 * @see Utf8#encodedLength(CharSequence)
 */
public static int utf8EncodedLength(@Nullable CharSequence sequence) {
	if (StringUtils.isEmpty(sequence)) {
		return 0;
	}
	return Utf8.encodedLength(sequence);
}
 

public static void sendMessageSplitLarge(PlayerContext ctx, Text text) {
    String json = TextSerializers.JSON.serialize(text);
    int size = Utf8.encodedLength(json);
    if (size > 32767) {
        List<Text> lines = ctx.utils().splitLines(text, ctx.width);
        ctx.getPlayer().sendMessages(lines);
    } else {
        ctx.getPlayer().sendMessage(text);
    }
}
 

/**
 * Item to show on chat message under this text.
 *
 * @param item {@link ItemStack}
 * @return instance of same {@link UltimateFancy}.
 */
public UltimateFancy hoverShowItem(ItemStack item) {
    JSONObject jItem = parseHoverItem(item);
    if (Utf8.encodedLength(jItem.toJSONString()) > 32767)
        pendentElements.add(new ExtraElement("hoverEvent", parseHoverItem(new ItemStack(item.getType()))));

    pendentElements.add(new ExtraElement("hoverEvent", jItem));
    return this;
}
 

private JSONObject parseHoverItem(ItemStack item) {
    JSONObject obj = new JSONObject();
    obj.put("action", "show_item");
    String jItem = convertItemStackToJson(item);
    if (Utf8.encodedLength(jItem) > 32767)
        obj.put("value", convertItemStackToJson(new ItemStack(item.getType())));

    obj.put("value", jItem);
    return obj;
}
 

/**
 * Item to show on chat message under this text.
 *
 * @param item {@link ItemStack}
 * @return instance of same {@link UltimateFancy}.
 */
public UltimateFancy hoverShowItem(ItemStack item) {
    JSONObject jItem = parseHoverItem(item);
    if (Utf8.encodedLength(jItem.toJSONString()) > 32767)
        pendentElements.add(new ExtraElement("hoverEvent", parseHoverItem(new ItemStack(item.getType()))));

    pendentElements.add(new ExtraElement("hoverEvent", jItem));
    return this;
}
 

private JSONObject parseHoverItem(ItemStack item) {
    JSONObject obj = new JSONObject();
    obj.put("action", "show_item");
    String jItem = convertItemStackToJson(item);
    if (Utf8.encodedLength(jItem) > 32767)
        obj.put("value", convertItemStackToJson(new ItemStack(item.getType())));

    obj.put("value", jItem);
    return obj;
}
 

public static int shortLengthStringSize(@Nullable final String string) {
    return Short.BYTES + ((string == null) ? 0 : Utf8.encodedLength(string));
}
 

@Override
public void read(
    final AsnObjectSerializationContext context,
    final AsnCharStringBasedObjectCodec instance,
    final InputStream inputStream
) throws IOException {

  Objects.requireNonNull(context);
  Objects.requireNonNull(instance);
  Objects.requireNonNull(inputStream);

  // WARNING: This length can be maliciously specified by the packet creator, so be careful not to use it for unsafe
  // operations, such as creating a new array of initial size `length`. This usage is safe because it merely caps the
  // InputStream to the specified packet-length, whereas the InputStream is authoritative for when it actually ends,
  // and this limit may be well smaller than `length`.
  int lengthToRead;
  final AsnSizeConstraint sizeConstraint = instance.getSizeConstraint();
  if (sizeConstraint.isFixedSize()) {
    lengthToRead = sizeConstraint.getMax();
  } else {
    // Read the lengthToRead of the encoded OctetString...
    lengthToRead = OerLengthSerializer.readLength(inputStream);
  }

  final String result;
  /* beware the 0-lengthToRead string */
  if (lengthToRead == 0) {
    result = "";
  } else {
    // Use a limited input stream so we don't read too many bytes.
    final InputStream limitedInputStream = ByteStreams.limit(inputStream, lengthToRead);
    // WARNING: Don't close the InputStreamReader so that the underlying inputStream is not closed.
    result = CharStreams.toString(new InputStreamReader(limitedInputStream, instance.getCharacterSet().name()));

    // For UTF-8 characters, result.length() will report the viewable length (e.g., 3) but for certain encoded
    // characters, the actual byte-length will be larger (e.g., the String 元元元 is 3 viewable bytes, but 9 encoded
    // UTF-8 bytes). Thus, when we write the length-prefix, the code will write 9, so when we read, we need to
    // validate that 9 bytes were read, and not 3 (in this example).
    if (Utf8.encodedLength(result) != lengthToRead) {
      throw new IOException(
          format("Unable to properly decode %s bytes (could only read %s bytes)", lengthToRead, result.length())
      );
    }
  }

  instance.setCharString(result);
}