* It uses the javax.xml.xpath.XPath and javax.xml.xpath.XPathFactory classes to create and evaluate XPath expressions.
 *
 * <p>Example usage:</p>
 * <pre>
 * {@code
 * XPathAPI xPathAPI = new XPathAPI();
 * NodeList nodes = xPathAPI.selectNodeList(contextNode, "//example");
 * Node singleNode = xPathAPI.selectSingleNode(contextNode, "//example[1]");

 * </ul>
 *
 * <h2>Usage Example:</h2>
 * <pre>
 * {@code
 * String escapedXml = XmlUtil.escapeXml("<tag>value</tag>");
 * Map<String, Object> dataMap = XmlUtil.getDataMap(accessResultData);
 * }
 * </pre>
 *
 * <h2>Thread Safety:</h2>
 * <p>
 * This class is thread-safe as it does not maintain any state.
 * </p>
 *
 * <h2>Dependencies:</h2>
 * <ul>

 * Exception thrown when there is an issue with the suggestion index.
 * This exception extends {@link SuggesterException}.
 *
 * <p>This exception can be thrown with a message, a cause, or both.</p>
 *
 * <pre>
 * Example usage:
 * throw new SuggestIndexException("Indexing error occurred");
 * throw new SuggestIndexException(new IOException("IO error"));
 * throw new SuggestIndexException("Indexing error", new IOException("IO error"));
 * </pre>
 *

    /** Map of metadata field names to their corresponding XPath expressions. */
    protected Map<String, String> metadataXpathMap = new HashMap<>();

    /** Thread-local instance of XPathAPI for thread-safe XPath evaluation. */
    private final ThreadLocal<XPathAPI> xpathAPI = new ThreadLocal<>();

    /**
     * Creates a new HtmlExtractor instance.
     */
    public HtmlExtractor() {
        super();
    }

/**
 * This class represents a custom exception for the suggester component.
 * It extends the {@link RuntimeException} class and provides constructors
 * to create an exception instance with a message, a cause, or both.
 *
 * <p>Usage examples:</p>
 * <pre>
 * throw new SuggesterException("An error occurred");
 * throw new SuggesterException(new IOException("IO error"));
 * throw new SuggesterException("An error occurred", new IOException("IO error"));

 *
 * <p>This class uses a specified Transliterator to perform text normalization.
 * The Transliterator is initialized with a given ID during the construction of
 * the ICUNormalizer instance.</p>
 *
 * <p>Example usage:</p>
 * <pre>
 * ICUNormalizer normalizer = new ICUNormalizer("Any-Latin; NFD; [:Nonspacing Mark:] Remove; NFC");
 * String normalizedText = normalizer.normalize("text to normalize", "field");
 * </pre>
 *

Add the dependency to your `pom.xml`:

```xml
<dependency>
    <groupId>org.codelibs.fess</groupId>
    <artifactId>fess-suggest</artifactId>
    <version>15.2.0-SNAPSHOT</version>
</dependency>
```

### Basic Usage

#### 1. Create Suggester Instance

```java
import org.codelibs.fess.suggest.Suggester;
import org.opensearch.client.Client;

// Initialize with your OpenSearch client
String suggestId = "my-suggest-index";

import java.util.List;

/**
 * The NormalizerChain class implements the Normalizer interface and allows chaining multiple normalizers together.
 * It applies each normalizer in the order they were added to the chain.
 *
 * <p>Usage example:</p>
 * <pre>
 * NormalizerChain chain = new NormalizerChain();
 * chain.add(new SomeNormalizer());
 * chain.add(new AnotherNormalizer());
 * String normalizedText = chain.normalize("input text", "field", "en");

Eine Ausstellung über den Erfinder der Thermoskanne Reinhold Burger ist zu besichtigen. Im Dorf selbst haben sich
zahlreiche Handwerker und Gewerbetreibende niedergelassen, denen über die Schulter geschaut bzw. mitgemacht
werden kann.
Für unsere Gruppe sind vier Workshops reserviert: Jeder Studierender muss sich bei der Anmeldung für die Fahrt für
einen verbindlich eintragen. Die Kosten dafür und das Mittagessen sind in den Fahrtkosten enthalten.
www.museumsdorf-glashuette.de

            + "^\\s*news:|" //
            + "^\\s*tel:|" //
            + "^\\s*unsaved:|" //
            + "^\\s*data:|" //
            + "^\\s*android-app:|" //
            + "^\\s*ios-app:|" //
            + "^\\s*callto:", Pattern.CASE_INSENSITIVE);

    /** Thread-local XPathAPI instance for thread-safe XPath operations. */
    private final ThreadLocal<XPathAPI> xpathAPI = new ThreadLocal<>();