/**
   * Encodes this entry using the V3 encoding.
   *
   * @param buffer The buffer to encode into.
   * @throws DirectoryException If a problem occurs while attempting to encode the entry.
   */
  private void encodeV2(Entry entry, ByteStringBuilder buffer, EntryEncodeConfig config)
      throws DirectoryException {
    // The version number will be one byte.
    buffer.appendByte(0x02);

    // Get the encoded respresentation of the config.
    config.encode(buffer);

    // If we should include the DN, then it will be encoded as a
    // one-to-five byte length followed by the UTF-8 byte
    // representation.
    if (!config.excludeDN()) {
      // TODO: Can we encode the DN directly into buffer?
      byte[] dnBytes = getBytes(entry.getName().toString());
      buffer.appendBERLength(dnBytes.length);
      buffer.appendBytes(dnBytes);
    }

    // Encode the object classes in the appropriate manner.
    if (config.compressObjectClassSets()) {
      config.getCompressedSchema().encodeObjectClasses(buffer, entry.getObjectClasses());
    } else {
      // Encode number of OCs and 0 terminated names.
      int i = 1;
      ByteStringBuilder bsb = new ByteStringBuilder();
      for (String ocName : entry.getObjectClasses().values()) {
        bsb.appendUtf8(ocName);
        if (i < entry.getObjectClasses().values().size()) {
          bsb.appendByte(0x00);
        }
        i++;
      }
      buffer.appendBERLength(bsb.length());
      buffer.appendBytes(bsb);
    }

    // Encode the user attributes in the appropriate manner.
    encodeV2Attributes(buffer, entry.getUserAttributes(), config);

    // The operational attributes will be encoded in the same way as
    // the user attributes.
    encodeV2Attributes(buffer, entry.getOperationalAttributes(), config);
  }
  private void encodeV2Attributes(
      ByteStringBuilder buffer,
      Map<AttributeType, List<Attribute>> attributes,
      EntryEncodeConfig config)
      throws DirectoryException {
    int numAttributes = 0;

    // First count how many attributes are there to encode.
    for (List<Attribute> attrList : attributes.values()) {
      for (Attribute a : attrList) {
        if (a.isVirtual() || a.isEmpty()) {
          continue;
        }

        numAttributes++;
      }
    }

    // Encoded one-to-five byte number of attributes
    buffer.appendBERLength(numAttributes);

    if (config.compressAttributeDescriptions()) {
      for (List<Attribute> attrList : attributes.values()) {
        for (Attribute a : attrList) {
          if (a.isVirtual() || a.isEmpty()) {
            continue;
          }

          ByteStringBuilder bsb = new ByteStringBuilder();
          config.getCompressedSchema().encodeAttribute(bsb, a);
          buffer.appendBERLength(bsb.length());
          buffer.appendBytes(bsb);
        }
      }
    } else {
      append(buffer, attributes);
    }
  }
  /**
   * Tests the entry encoding and decoding process the version 1 encoding.
   *
   * @throws Exception If the test failed unexpectedly.
   */
  @Test(dataProvider = "encodeConfigs")
  public void testEntryToAndFromDatabaseV3(EntryEncodeConfig config) throws Exception {
    ensureServerIsUpAndRunning();

    // Convert the test LDIF string to a byte array
    byte[] originalLDIFBytes = StaticUtils.getBytes(ldifString);

    try (final LDIFReader reader =
        new LDIFReader(new LDIFImportConfig(new ByteArrayInputStream(originalLDIFBytes)))) {
      Entry entryBefore, entryAfterV3;
      while ((entryBefore = reader.readEntry(false)) != null) {
        ByteStringBuilder bsb = new ByteStringBuilder();
        entryBefore.encode(bsb, config);
        entryAfterV3 = Entry.decode(bsb.asReader());
        if (config.excludeDN()) {
          entryAfterV3.setDN(entryBefore.getName());
        }
        assertEquals(entryBefore, entryAfterV3);
      }
    }
  }