MediaType.java 文件源码

/**
 * <em>Replaces</em> all parameters with the given attribute with a single parameter with the
 * given value. If multiple parameters with the same attributes are necessary use
 * {@link #withParameters}. Prefer {@link #withCharset} for setting the {@code charset} parameter
 * when using a {@link Charset} object.
 *
 * @throws IllegalArgumentException if either {@code attribute} or {@code value} is invalid
 */
public MediaType withParameter(String attribute, String value) {
  checkNotNull(attribute);
  checkNotNull(value);
  String normalizedAttribute = normalizeToken(attribute);
  ImmutableListMultimap.Builder<String, String> builder = ImmutableListMultimap.builder();
  for (Entry<String, String> entry : parameters.entries()) {
    String key = entry.getKey();
    if (!normalizedAttribute.equals(key)) {
      builder.put(key, entry.getValue());
    }
  }
  builder.put(normalizedAttribute, normalizeParameterValue(normalizedAttribute, value));
  MediaType mediaType = new MediaType(type, subtype, builder.build());
  // Return one of the constants if the media type is a known type.
  return MoreObjects.firstNonNull(KNOWN_TYPES.get(mediaType), mediaType);
}