public Model merge(Model target, Model source, boolean sourceDominant, Map<?, ?> hints) {
        return super.merge(target, source, sourceDominant, hints);
    }

    @Override
    protected Model mergeModel(Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
        context.put(ARTIFACT_ID, target.getArtifactId());

        return super.mergeModel(target, source, sourceDominant, context);
    }

	// S3 extensions
	AmzCopySourceIfModifiedSince   = "x-amz-copy-source-if-modified-since"
	AmzCopySourceIfUnmodifiedSince = "x-amz-copy-source-if-unmodified-since"

	AmzCopySourceIfNoneMatch = "x-amz-copy-source-if-none-match"
	AmzCopySourceIfMatch     = "x-amz-copy-source-if-match"

	AmzCopySource                 = "X-Amz-Copy-Source"
	AmzCopySourceVersionID        = "X-Amz-Copy-Source-Version-Id"

     * optional. If present, it contains the TLS version.
     */
    @Throws(IOException::class)
    constructor(rawSource: Source) {
      rawSource.use {
        val source = rawSource.buffer()
        val urlLine = source.readUtf8LineStrict()
        // Choice here is between failing with a correct RuntimeException
        // or mostly silently with an IOException

    }
  }

  /**
   * Returns the trailers. It is only safe to call this once the source stream has been completely
   * exhausted.
   */
  @Throws(IOException::class)
  fun trailers(): Headers {
    this.withLock {
      if (source.finished && source.receiveBuffer.exhausted() && source.readBuffer.exhausted()) {
        return source.trailers ?: EMPTY_HEADERS
      }
      if (errorCode != null) {

            result.setCreatedTime(DfTypeUtil.toLong(source.get("createdTime")));
            result.setDepth(DfTypeUtil.toInteger(source.get("depth")));
            result.setDescription(DfTypeUtil.toString(source.get("description")));
            result.setExcludedDocPaths(DfTypeUtil.toString(source.get("excludedDocPaths")));
            result.setExcludedPaths(DfTypeUtil.toString(source.get("excludedPaths")));

            result.setLanguages(DfTypeUtil.toString(source.get("languages")));
            result.setQueryId(DfTypeUtil.toString(source.get("queryId")));
            result.setQueryOffset(DfTypeUtil.toInteger(source.get("queryOffset")));
            result.setQueryPageSize(DfTypeUtil.toInteger(source.get("queryPageSize")));
            result.setQueryTime(DfTypeUtil.toLong(source.get("queryTime")));

            result.setDescription(DfTypeUtil.toString(source.get("description")));
            result.setHandlerName(DfTypeUtil.toString(source.get("handlerName")));
            result.setHandlerParameter(DfTypeUtil.toString(source.get("handlerParameter")));
            result.setHandlerScript(DfTypeUtil.toString(source.get("handlerScript")));
            result.setName(DfTypeUtil.toString(source.get("name")));

            result.setDescription(DfTypeUtil.toString(source.get("description")));
            result.setDestinationIndicator(DfTypeUtil.toString(source.get("destinationIndicator")));
            result.setDisplayName(DfTypeUtil.toString(source.get("displayName")));
            result.setEmployeeNumber(DfTypeUtil.toString(source.get("employeeNumber")));

            result.setName(DfTypeUtil.toString(source.get("name")));
            result.setPermissions(toStringArray(source.get("permissions")));
            result.setSortOrder(DfTypeUtil.toInteger(source.get("sortOrder")));
            result.setUpdatedBy(DfTypeUtil.toString(source.get("updatedBy")));
            result.setUpdatedTime(DfTypeUtil.toLong(source.get("updatedTime")));

        source.put("aaa", "");
        source.put("bbb", "a");
        assertFalse(fessConfig.validateIndexRequiredFields(source));
        source.put("aaa", " ");
        source.put("bbb", "a");
        assertFalse(fessConfig.validateIndexRequiredFields(source));
        source.put("aaa", "a");
        source.put("bbb", "a");