public Converter<String, String> converterTo(CaseFormat targetFormat) {
    return new StringConverter(this, targetFormat);
  }

  private static final class StringConverter extends Converter<String, String>
      implements Serializable {

    private final CaseFormat sourceFormat;
    private final CaseFormat targetFormat;

    StringConverter(CaseFormat sourceFormat, CaseFormat targetFormat) {

  public Converter<String, String> converterTo(CaseFormat targetFormat) {
    return new StringConverter(this, targetFormat);
  }

  private static final class StringConverter extends Converter<String, String>
      implements Serializable {

    private final CaseFormat sourceFormat;
    private final CaseFormat targetFormat;

    StringConverter(CaseFormat sourceFormat, CaseFormat targetFormat) {

 */

package com.google.common.base;

import static com.google.common.base.CaseFormat.LOWER_CAMEL;
import static com.google.common.base.CaseFormat.LOWER_HYPHEN;
import static com.google.common.base.CaseFormat.LOWER_UNDERSCORE;
import static com.google.common.base.CaseFormat.UPPER_CAMEL;
import static com.google.common.base.CaseFormat.UPPER_UNDERSCORE;
import static com.google.common.truth.Truth.assertThat;

            return key;
        }
        String keyStr = key.toString();
        if (keyStr.indexOf('_') < 0) {
            keyStr = CaseFormat.LOWER_CAMEL.to(CaseFormat.LOWER_UNDERSCORE, StringUtils.uncapitalize(keyStr));
        } else {
            keyStr = CaseFormat.LOWER_UNDERSCORE.to(CaseFormat.LOWER_CAMEL, keyStr);
        }
        return keyStr;
    }

    @Override
    public int size() {
        return parent.size();

 * library.
 *
 * <h2>Contents</h2>
 *
 * The classes in this package that are most commonly useful are:
 *
 * <h3>String utilities</h3>
 *
 * <ul>
 *   <li>{@link Ascii}
 *   <li>{@link CaseFormat}
 *   <li>{@link CharMatcher}
 *   <li>{@link Splitter}
 *   <li>{@link Strings}
 * </ul>
 *
 * <h3>Function types</h3>
 *
 * <ul>
 *   <li>{@link Converter}
 *   <li>{@link Equivalence}
 * </ul>