import java.util.function.BiFunction;
import java.util.function.Function;

import org.apache.commons.lang3.StringUtils;

import com.google.common.base.CaseFormat;

/**
 * Parameter map that converts between camelCase and snake_case.
 *
 * @param <K> the key type
 * @param <V> the value type
 */
public class ParamMap<K, V> implements Map<K, V> {

    private final Map<K, V> parent;

    /**

 * data store specific parameters with type-safe access methods.
 *
 * <p>The class uses a ParamMap internally which provides case format conversion
 * between camelCase and snake_case parameter names for flexible parameter access.
 * Parameters can be stored as any Object type and retrieved with type conversion
 * support for common types like String.</p>
 *

| Element | Convention | Example |
|---------|------------|---------|
| Classes | PascalCase | `UserService`, `FessBaseAction` |
| Methods | camelCase + verb | `getUserList()`, `setupHtmlData()` |
| Constants | UPPER_SNAKE_CASE | `DEFAULT_PAGE_SIZE` |
| Fields | camelCase | `userPager`, `fessConfig` |

## Log Message Guidelines

- Logger: `LogManager.getLogger(ClassName.class)`

- **Indentation**: 4 spaces (no tabs)
- **Line Length**: 140 characters max
- **License Headers**: Required (use `mvn license:format`)

### Naming & Style

Standard Java conventions (PascalCase classes, camelCase methods, UPPER_SNAKE_CASE constants). Add JavaDoc with `@param`, `@return`, `@throws` for new public APIs.

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## Quick Reference

### Essential Files

| File | Purpose |
|------|---------|