* otherwise returns an empty stream.
   */
  public static <T> Stream<T> stream(com.google.common.base.Optional<T> optional) {
    return optional.isPresent() ? Stream.of(optional.get()) : Stream.empty();
  }

  /**
   * If a value is present in {@code optional}, returns a stream containing only that element,
   * otherwise returns an empty stream.
   *

                wConfig.setExcludedUrls(getDefaultString("default.config.web.excludedUrls", StringUtil.EMPTY));
                wConfig.setIncludedDocUrls(getDefaultString("default.config.web.includedDocUrls", StringUtil.EMPTY));
                wConfig.setIncludedUrls(getDefaultString("default.config.web.includedUrls", StringUtil.EMPTY));

            return Optional.of(Boolean.TRUE);
        }
        return Optional.empty();
    }

    @Override
    public Optional<Boolean> yes() {
        if (commandLine.hasOption(CLIManager.YES)) {
            return Optional.of(Boolean.TRUE);
        }
        return Optional.empty();
    }

    @Override
    public Optional<List<String>> goals() {

     *
     * @return The group id of the unresolvable model, can be empty but never {@code null}.
     */
    public String getGroupId() {
        return groupId;
    }

    /**
     * Gets the artifact id of the unresolvable model.
     *
     * @return The artifact id of the unresolvable model, can be empty but never {@code null}.
     */
    public String getArtifactId() {

			expectedErr: errInvalidRuleID,
		},
		{ // Rule with empty ID
			inputXML: `<Rule>
							<ID></ID>
							<Filter><Prefix></Prefix></Filter>
							<Expiration>
								<Days>365</Days>
							</Expiration>
                            <Status>Enabled</Status>
	                    </Rule>`,
			expectedErr: nil,
		},
		{ // Rule with empty status
			inputXML: ` <Rule>

// client setting, note this will fail if set to empty when
// constructor initializes.
func DomainNames(domainNames []string) EtcdOption {
	return func(args *CoreDNS) {
		args.domainNames = domainNames
	}
}

// DomainIPs set a list of custom domain IPs, note this will
// fail if set to empty when constructor initializes.
func DomainIPs(domainIPs set.StringSet) EtcdOption {

   *     // operate on tuple
   *   }
   * }
   * }</pre>
   *
   * <p>Note that if any input set is empty, the Cartesian product will also be empty. If no sets at
   * all are provided (an empty list), the resulting Cartesian product has one element, an empty
   * list (counter-intuitive, but mathematically consistent).
   *

}

// Empty returns true for a target if arn is empty
func (rt replicatedTargetInfo) Empty() bool {
	return rt.Arn == ""
}

type replicatedInfos struct {
	ReplicationTimeStamp time.Time
	Targets              []replicatedTargetInfo
}

func (ri replicatedInfos) CompletedSize() (sz int64) {
	for _, t := range ri.Targets {
		if t.Empty() {
			continue
		}

	Replica StatusType = "REPLICA"
)

// String returns string representation of status
func (s StatusType) String() string {
	return string(s)
}

// Empty returns true if this status is not set
func (s StatusType) Empty() bool {
	return string(s) == ""

                    postcard.setCrawlerExecTime(getValueFromMap(dataMap, "crawlerExecTime", "0"));
                    postcard.setCrawlerStartTime(getValueFromMap(dataMap, "crawlerStartTime", StringUtil.EMPTY));
                    postcard.setDataCrawlEndTime(getValueFromMap(dataMap, "dataCrawlEndTime", StringUtil.EMPTY));