/**
  * Create a new child DN from a given parent DN. The child RDN is formed from a given attribute
  * type and string value.
  *
  * @param parentDN The DN of the parent.
  * @param rdnAttrType The attribute type of the RDN.
  * @param rdnStringValue The string value of the RDN.
  * @return A new child DN.
  */
 public static DN makeChildDN(DN parentDN, AttributeType rdnAttrType, String rdnStringValue) {
   AttributeValue attrValue = AttributeValues.create(rdnAttrType, rdnStringValue);
   return parentDN.concat(RDN.create(rdnAttrType, attrValue));
 }
  /** {@inheritDoc} */
  @Override
  public void initializeBackend() throws ConfigException, InitializationException {
    // Create the set of base DNs that we will handle.  In this case, it's just
    // the DN of the base backup entry.
    try {
      backupBaseDN = DN.decode(DN_BACKUP_ROOT);
    } catch (Exception e) {
      if (debugEnabled()) {
        TRACER.debugCaught(DebugLogLevel.ERROR, e);
      }

      Message message =
          ERR_BACKEND_CANNOT_DECODE_BACKEND_ROOT_DN.get(getExceptionMessage(e), getBackendID());
      throw new InitializationException(message, e);
    }

    // FIXME -- Deal with this more correctly.
    this.baseDNs = new DN[] {backupBaseDN};

    // Determine the set of backup directories that we will use by default.
    Set<String> values = currentConfig.getBackupDirectory();
    backupDirectories = new LinkedHashSet<File>(values.size());
    for (String s : values) {
      backupDirectories.add(getFileForPath(s));
    }

    // Construct the backup base entry.
    LinkedHashMap<ObjectClass, String> objectClasses = new LinkedHashMap<ObjectClass, String>(2);
    objectClasses.put(DirectoryServer.getTopObjectClass(), OC_TOP);

    ObjectClass untypedOC = DirectoryServer.getObjectClass(OC_UNTYPED_OBJECT_LC, true);
    objectClasses.put(untypedOC, OC_UNTYPED_OBJECT);

    LinkedHashMap<AttributeType, List<Attribute>> opAttrs =
        new LinkedHashMap<AttributeType, List<Attribute>>(0);
    LinkedHashMap<AttributeType, List<Attribute>> userAttrs =
        new LinkedHashMap<AttributeType, List<Attribute>>(1);

    RDN rdn = backupBaseDN.getRDN();
    int numAVAs = rdn.getNumValues();
    for (int i = 0; i < numAVAs; i++) {
      AttributeType attrType = rdn.getAttributeType(i);
      ArrayList<Attribute> attrList = new ArrayList<Attribute>(1);
      attrList.add(Attributes.create(attrType, rdn.getAttributeValue(i)));

      userAttrs.put(attrType, attrList);
    }

    backupBaseEntry = new Entry(backupBaseDN, objectClasses, userAttrs, opAttrs);

    currentConfig.addBackupChangeListener(this);

    // Register the backup base as a private suffix.
    try {
      DirectoryServer.registerBaseDN(backupBaseDN, this, true);
    } catch (Exception e) {
      if (debugEnabled()) {
        TRACER.debugCaught(DebugLogLevel.ERROR, e);
      }

      Message message =
          ERR_BACKEND_CANNOT_REGISTER_BASEDN.get(backupBaseDN.toString(), getExceptionMessage(e));
      throw new InitializationException(message, e);
    }
  }