public abstract class CharEscaper extends Escaper {
  /** Constructor for use by subclasses. */
  protected CharEscaper() {}

  /**
   * Returns the escaped form of a given literal string.
   *
   * @param string the literal string to be escaped
   * @return the escaped form of {@code string}
   * @throws NullPointerException if {@code string} is null
   */
  @Override
  public String escape(String string) {

    assertUnicodeEscaping(e, "%F4%8F%BF%BF", '\uDBFF', '\uDFFF');

    // simple string tests
    assertThat(e.escape("")).isEqualTo("");
    assertThat(e.escape("safestring")).isEqualTo("safestring");
    assertThat(e.escape("embedded\0null")).isEqualTo("embedded%00null");
    assertThat(e.escape("max\uffffchar")).isEqualTo("max%EF%BF%BFchar");
  }

  /** Tests the various ways that the space character can be handled */

    assertThat(e.escape("")).isEqualTo("");
    assertThat(e.escape("safestring")).isEqualTo("safestring");
    assertThat(e.escape("embedded\0null")).isEqualTo("embedded%00null");
    assertThat(e.escape("max\uffffchar")).isEqualTo("max%EF%BF%BFchar");
  }

  // Helper to assert common expected behaviour of uri escapers.
  static void assertBasicUrlEscaper(UnicodeEscaper e) {

    assertUnicodeEscaping(e, "%F4%8F%BF%BF", '\uDBFF', '\uDFFF');

    // simple string tests
    assertThat(e.escape("")).isEqualTo("");
    assertThat(e.escape("safestring")).isEqualTo("safestring");
    assertThat(e.escape("embedded\0null")).isEqualTo("embedded%00null");
    assertThat(e.escape("max\uffffchar")).isEqualTo("max%EF%BF%BFchar");
  }

  /** Tests the various ways that the space character can be handled */

 * the License.
 */

/**
 * Interfaces, utilities, and simple implementations of escapers and encoders. The primary type is
 * {@link Escaper}.
 *
 * <p>Additional escapers implementations are found in the applicable packages: {@link
 * com.google.common.html.HtmlEscapers} in {@code com.google.common.html}, {@link

    assertThat(e.escape("")).isEqualTo("");
    assertThat(e.escape("safestring")).isEqualTo("safestring");
    assertThat(e.escape("embedded\0null")).isEqualTo("embedded%00null");
    assertThat(e.escape("max\uffffchar")).isEqualTo("max%EF%BF%BFchar");
  }

  // Helper to assert common expected behaviour of uri escapers.
  static void assertBasicUrlEscaper(UnicodeEscaper e) {

 * highest valued code point that requires escaping. For example a replacement map containing the
 * single character '{@code \}{@code u1000}' will require approximately 16K of memory. If you need
 * to create multiple escaper instances that have the same character replacement mapping consider
 * using {@link ArrayBasedEscaperMap}.
 *
 * @author David Beaumont
 * @since 15.0
 */
@GwtCompatible

   */
  @Override
  public final String escape(String s) {
    checkNotNull(s); // GWT specific check (do not optimize).
    for (int i = 0; i < s.length(); i++) {
      char c = s.charAt(i);
      if ((c < replacementsLength && replacements[c] != null) || c > safeMax || c < safeMin) {
        return escapeSlow(s, i);
      }
    }
    return s;
  }

  /**

    // Test quotes are escaped.
    assertThat(xmlAttributeEscaper.escape("\"test\"")).isEqualTo(""test"");
    assertThat(xmlAttributeEscaper.escape("'test'")).isEqualTo("'test'");
    // Test all escapes
    assertThat(xmlAttributeEscaper.escape("a\"b<c>d&e\"f'"))
        .isEqualTo("a&quot;b&lt;c&gt;d&amp;e&quot;f&apos;");
    // Test '\t', '\n' and '\r' are escaped.

    // Test quotes are escaped.
    assertThat(xmlAttributeEscaper.escape("\"test\"")).isEqualTo(""test"");
    assertThat(xmlAttributeEscaper.escape("'test'")).isEqualTo("'test'");
    // Test all escapes
    assertThat(xmlAttributeEscaper.escape("a\"b<c>d&e\"f'"))
        .isEqualTo("a&quot;b&lt;c&gt;d&amp;e&quot;f&apos;");
    // Test '\t', '\n' and '\r' are escaped.