* 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");

            + "^\\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<>();

 * {@link java.net.IDN} class.
 *
 * <p>This class allows setting a custom flag for the IDN conversion and a custom
 * encoding for URL decoding.</p>
 *
 * <p>Example usage:</p>
 * <pre>
 * {@code
 * IdnDnsResolver resolver = new IdnDnsResolver();
 * resolver.setFlag(IDN.ALLOW_UNASSIGNED);
 * resolver.setEncoding("UTF-8");
 * InetAddress[] addresses = resolver.resolve("example.com");
 * }