public static DirContextOperations searchForSingleEntryInternal(DirContext ctx,
			SearchControls searchControls, String base, String filter, Object[] params)
			throws NamingException {
		final DistinguishedName ctxBaseDn = new DistinguishedName(
				ctx.getNameInNamespace());
		final DistinguishedName searchBaseDn = new DistinguishedName(base);
		final NamingEnumeration<SearchResult> resultsEnum = ctx.search(searchBaseDn,
				filter, params, buildControls(searchControls));

		if (logger.isDebugEnabled()) {
			logger.debug("Searching for entry under DN '" + ctxBaseDn + "', base = '"
					+ searchBaseDn + "', filter = '" + filter + "'");
		}

		Set<DirContextOperations> results = new HashSet<>();
		try {
			while (resultsEnum.hasMore()) {
				SearchResult searchResult = resultsEnum.next();
				DirContextAdapter dca = (DirContextAdapter) searchResult.getObject();
				Assert.notNull(dca,
						"No object returned by search, DirContext is not correctly configured");

				if (logger.isDebugEnabled()) {
					logger.debug("Found DN: " + dca.getDn());
				}
				results.add(dca);
			}
		}
		catch (PartialResultException e) {
			LdapUtils.closeEnumeration(resultsEnum);
			logger.info("Ignoring PartialResultException");
		}

		if (results.size() == 0) {
			throw new IncorrectResultSizeDataAccessException(1, 0);
		}

		if (results.size() > 1) {
			throw new IncorrectResultSizeDataAccessException(1, results.size());
		}

		return results.iterator().next();
	}