}

    def "creates sub version selector"() {
        expect:
        matcher.parseSelector(selector) instanceof SubVersionSelector

        where:
        selector << [
            "1+",
            "1.2.3+"
        ]
    }

    def "creates latest version selector"() {
        expect:
        matcher.parseSelector(selector) instanceof LatestVersionSelector

        where:
        selector << [

        isStrict = !strictVersion.isEmpty();
        String version = isStrict ? strictVersion : requiredVersion;
        this.requiredVersionSelector = scheme.parseSelector(version);
        this.preferredVersionSelector = preferredVersion.isEmpty() ? null : scheme.parseSelector(preferredVersion);

        if (isStrict) {
            VersionSelector rejectionForStrict = getRejectionForStrict(version, scheme);

    def mapper = new MavenVersionSelectorScheme(defaultMatcher)

    def "translates to maven syntax"() {
        given:
        def selector = defaultMatcher.parseSelector(input)

        expect:
        mapper.renderSelector(selector) == output

        where:
        input                | output
        "]2,3]"              | "(2,3]"
        "[2,3["              | "[2,3)"

        this.delegate = delegate;
    }

    @Override
    public VersionSelector parseSelector(String selectorString) {
        VersionSelector versionSelector = cachedSelectors.get(selectorString);
        if (versionSelector == null) {
            versionSelector = delegate.parseSelector(selectorString);
            cachedSelectors.put(selectorString, versionSelector);
        }
        return versionSelector;

	return Selector{
		present: NewSet(present...),
		absent:  NewSet(absent...),
	}
}

var userLabelRegex = regexp.MustCompile(`^[a-zA-Z][a-zA-Z0-9_]*(\.[a-zA-Z0-9_]+)*$`)

// ParseSelector parses and returns a new instance of Selector.
func ParseSelector(s string) (Selector, error) {
	var present, absent []Instance

	parts := strings.Split(s, ",")
	for _, p := range parts {
		if len(p) == 0 {
			continue
		}

    }

    @Override
    public VersionSelector parseSelector(String selectorString) {
        if (selectorString.equals(RELEASE)) {
            return new LatestVersionSelector(LATEST_RELEASE);
        } else if (selectorString.equals(LATEST)) {
            return new LatestVersionSelector(LATEST_INTEGRATION);
        } else {
            return defaultVersionSelectorScheme.parseSelector(selectorString);
        }
    }

    @Override

    }

    @Override
    public String map(String version) {
        return mavenVersionSelectorScheme.renderSelector(defaultVersionSelectorScheme.parseSelector(version));
    }

}

// Set is a map of field:value. It implements Fields.
type Set map[string]string

// String returns all fields listed as a human readable string.
// Conveniently, exactly the format that ParseSelector takes.
func (ls Set) String() string {
	selector := make([]string, 0, len(ls))
	for key, value := range ls {
		selector = append(selector, key+"="+value)
	}
	// Sort for determinism.

        selectors.each {
            members.add(selectorOf(it))
        }
    }

    private VersionSelector selectorOf(String selectorString) {
        versionSelectorScheme.parseSelector(selectorString)
    }

    private Version versionOf(String candidate) {
        parser.transform(candidate)
    }

    private ComponentMetadata metadataFor(String candidate) {

     *
     * @param selectorString - the string representation of the selector
     * @return the {@link VersionSelector}
     */
    VersionSelector parseSelector(String selectorString);

    /**
     * Renders a {@link VersionSelector} to a selector string.
     */
    String renderSelector(VersionSelector selector);

    /**