/**
     * Adds a client with a regular expression pattern.
     * @param regex The regular expression to match URLs.
     * @param client The CrawlerClient instance.
     */
    public void addClient(final String regex, final CrawlerClient client) {
        if (StringUtil.isBlank(regex)) {
            throw new CrawlerSystemException(

                PrimaryExpr TypeAssertion |
                PrimaryExpr Arguments .

Selector      = "." identifier .
Index         = "[" Expression [ "," ] "]" .
Slice         = "[" [ Expression ] ":" [ Expression ] "]" |
                "[" [ Expression ] ":" Expression ":" Expression "]" .
TypeAssertion = "." "(" Type ")" .
Arguments     = "(" [ ( ExpressionList | Type [ "," ExpressionList ] ) [ "..." ] [ "," ] ] ")" .
</pre>

* The *path* can contain an <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.1.0.md#key-expression" class="external-link" target="_blank">OpenAPI 3 expression</a> (see more below) where it can use variables with parameters and parts of the original request sent to *your API*.

### The callback path expression { #the-callback-path-expression }

    /** HTTP header name for robots tag */
    private static final String X_ROBOTS_TAG = "X-Robots-Tag";

    /** XPath expression for extracting thumbnail content from meta tags */
    private static final String META_NAME_THUMBNAIL_CONTENT = "//META[@name=\"thumbnail\" or @name=\"THUMBNAIL\"]/@content";

    /** XPath expression for extracting Open Graph image content from meta tags */

		</antcall>
		<!-- lang-expression -->
		<antcall target="install.module">
			<param name="repo.url" value="${maven.release.repo.url}" />
			<param name="module.groupId" value="org/codelibs/opensearch/module" />
			<param name="module.name.prefix" value="" />
			<param name="module.name" value="lang-expression" />
			<param name="module.version" value="${opensearch.version}" />

                        logger.debug("Path {} matches the exclude path expression {} on {} of label.", path, excludedPaths, value);
                    }
                    return false;
                }
                if (logger.isDebugEnabled()) {
                    logger.debug("Path {} does not match the exclude path expression {} on {} of label.", path, excludedPaths, value);
                }

* O *path* pode conter uma <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.1.0.md#key-expression" class="external-link" target="_blank">expressão OpenAPI 3</a> (veja mais abaixo) em que pode usar variáveis com parâmetros e partes da solicitação original enviada para *sua API*.

### A expressão do path do callback { #the-callback-path-expression }

* El *path* puede contener una <a href="https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.1.0.md#key-expression" class="external-link" target="_blank">expresión OpenAPI 3</a> (ver más abajo) donde puede usar variables con parámetros y partes del request original enviado a *tu API*.

### La expresión del path del callback { #the-callback-path-expression }

    @Override
    public void close() {
        clientFactory.close();
    }

    /**
     * Adds an include filter for URLs.
     * Only URLs matching this regular expression will be crawled.
     * @param regexp The regular expression for the include filter.
     */
    public void addIncludeFilter(final String regexp) {
        if (StringUtil.isNotBlank(regexp)) {
            urlFilter.addInclude(regexp);
        }

   * IllegalStateException} if it is accessed in any way, with the following exceptions:
   *
   * <ul>
   *   <li>{@code view.equals(view)} evaluates to {@code true} (but any other {@code equals(...)}
   *       expression involving {@code view} will throw)
   *   <li>{@code hashCode()} does not throw
   *   <li>if {@code node} is re-added to the graph after having been removed, {@code view}'s
   *       behavior is undefined
   * </ul>
   *