How to use

isValidSchemeChar

method

in

libcore.net.url.UrlUtils

private String validateScheme(String uri, int end) throws URISyntaxException {
  if (end == 0) {
    throw new URISyntaxException(uri, "Scheme expected", 0);
  }
  for (int i = 0; i < end; i++) {
    if (!UrlUtils.isValidSchemeChar(i, uri.charAt(i))) {
      throw new URISyntaxException(uri, "Illegal character in scheme", 0);
    }
  }
  return uri.substring(0, end);
}

/**
 * Returns the scheme prefix like "http" from the URL spec, or null if the
 * spec doesn't start with a scheme. Scheme prefixes match this pattern:
 * {@code alpha ( alpha | digit | '+' | '-' | '.' )* ':'}
 */
public static String getSchemePrefix(String spec) {
  int colon = spec.indexOf(':');
  if (colon < 1) {
    return null;
  }
  for (int i = 0; i < colon; i++) {
    char c = spec.charAt(i);
    if (!isValidSchemeChar(i, c)) {
      return null;
    }
  }
  return spec.substring(0, colon).toLowerCase(Locale.US);
}

private String validateScheme(String uri, int end) throws URISyntaxException {
  if (end == 0) {
    throw new URISyntaxException(uri, "Scheme expected", 0);
  }
  for (int i = 0; i < end; i++) {
    if (!UrlUtils.isValidSchemeChar(i, uri.charAt(i))) {
      throw new URISyntaxException(uri, "Illegal character in scheme", 0);
    }
  }
  return uri.substring(0, end);
}

private String validateScheme(String uri, int end) throws URISyntaxException {
  if (end == 0) {
    throw new URISyntaxException(uri, "Scheme expected", 0);
  }
  for (int i = 0; i < end; i++) {
    if (!UrlUtils.isValidSchemeChar(i, uri.charAt(i))) {
      throw new URISyntaxException(uri, "Illegal character in scheme", 0);
    }
  }
  return uri.substring(0, end);
}

private String validateScheme(String uri, int end) throws URISyntaxException {
  if (end == 0) {
    throw new URISyntaxException(uri, "Scheme expected", 0);
  }
  for (int i = 0; i < end; i++) {
    if (!UrlUtils.isValidSchemeChar(i, uri.charAt(i))) {
      throw new URISyntaxException(uri, "Illegal character in scheme", 0);
    }
  }
  return uri.substring(0, end);
}

private String validateScheme(String uri, int end) throws URISyntaxException {
  if (end == 0) {
    throw new URISyntaxException(uri, "Scheme expected", 0);
  }
  for (int i = 0; i < end; i++) {
    if (!UrlUtils.isValidSchemeChar(i, uri.charAt(i))) {
      throw new URISyntaxException(uri, "Illegal character in scheme", 0);
    }
  }
  return uri.substring(0, end);
}

private String validateScheme(String uri, int end) throws URISyntaxException {
  if (end == 0) {
    throw new URISyntaxException(uri, "Scheme expected", 0);
  }
  for (int i = 0; i < end; i++) {
    if (!UrlUtils.isValidSchemeChar(i, uri.charAt(i))) {
      throw new URISyntaxException(uri, "Illegal character in scheme", 0);
    }
  }
  return uri.substring(0, end);
}

private String validateScheme(String uri, int end) throws URISyntaxException {
  if (end == 0) {
    throw new URISyntaxException(uri, "Scheme expected", 0);
  }
  for (int i = 0; i < end; i++) {
    if (!UrlUtils.isValidSchemeChar(i, uri.charAt(i))) {
      throw new URISyntaxException(uri, "Illegal character in scheme", 0);
    }
  }
  return uri.substring(0, end);
}

/**
 * Returns the scheme prefix like "http" from the URL spec, or null if the
 * spec doesn't start with a scheme. Scheme prefixes match this pattern:
 * {@code alpha ( alpha | digit | '+' | '-' | '.' )* ':'}
 */
public static String getSchemePrefix(String spec) {
  int colon = spec.indexOf(':');
  if (colon < 1) {
    return null;
  }
  for (int i = 0; i < colon; i++) {
    char c = spec.charAt(i);
    if (!isValidSchemeChar(i, c)) {
      return null;
    }
  }
  return spec.substring(0, colon).toLowerCase(Locale.US);
}

/**
 * Returns the scheme prefix like "http" from the URL spec, or null if the
 * spec doesn't start with a scheme. Scheme prefixes match this pattern:
 * {@code alpha ( alpha | digit | '+' | '-' | '.' )* ':'}
 */
public static String getSchemePrefix(String spec) {
  int colon = spec.indexOf(':');
  if (colon < 1) {
    return null;
  }
  for (int i = 0; i < colon; i++) {
    char c = spec.charAt(i);
    if (!isValidSchemeChar(i, c)) {
      return null;
    }
  }
  return spec.substring(0, colon).toLowerCase(Locale.US);
}

/**
 * Returns the scheme prefix like "http" from the URL spec, or null if the
 * spec doesn't start with a scheme. Scheme prefixes match this pattern:
 * {@code alpha ( alpha | digit | '+' | '-' | '.' )* ':'}
 */
public static String getSchemePrefix(String spec) {
  int colon = spec.indexOf(':');
  if (colon < 1) {
    return null;
  }
  for (int i = 0; i < colon; i++) {
    char c = spec.charAt(i);
    if (!isValidSchemeChar(i, c)) {
      return null;
    }
  }
  return spec.substring(0, colon).toLowerCase(Locale.US);
}

/**
 * Returns the scheme prefix like "http" from the URL spec, or null if the
 * spec doesn't start with a scheme. Scheme prefixes match this pattern:
 * {@code alpha ( alpha | digit | '+' | '-' | '.' )* ':'}
 */
public static String getSchemePrefix(String spec) {
  int colon = spec.indexOf(':');
  if (colon < 1) {
    return null;
  }
  for (int i = 0; i < colon; i++) {
    char c = spec.charAt(i);
    if (!isValidSchemeChar(i, c)) {
      return null;
    }
  }
  return spec.substring(0, colon).toLowerCase(Locale.US);
}

/**
 * Returns the scheme prefix like "http" from the URL spec, or null if the
 * spec doesn't start with a scheme. Scheme prefixes match this pattern:
 * {@code alpha ( alpha | digit | '+' | '-' | '.' )* ':'}
 */
public static String getSchemePrefix(String spec) {
  int colon = spec.indexOf(':');
  if (colon < 1) {
    return null;
  }
  for (int i = 0; i < colon; i++) {
    char c = spec.charAt(i);
    if (!isValidSchemeChar(i, c)) {
      return null;
    }
  }
  return spec.substring(0, colon).toLowerCase(Locale.US);
}

/**
 * Returns the scheme prefix like "http" from the URL spec, or null if the
 * spec doesn't start with a scheme. Scheme prefixes match this pattern:
 * {@code alpha ( alpha | digit | '+' | '-' | '.' )* ':'}
 */
public static String getSchemePrefix(String spec) {
  int colon = spec.indexOf(':');
  if (colon < 1) {
    return null;
  }
  for (int i = 0; i < colon; i++) {
    char c = spec.charAt(i);
    if (!isValidSchemeChar(i, c)) {
      return null;
    }
  }
  return spec.substring(0, colon).toLowerCase(Locale.US);
}