content: /*
   * Copyright The OpenTelemetry Authors
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package io.opentelemetry.javaagent.instrumentation.restlet.v2_0;
  
  import io.opentelemetry.instrumentation.restlet.v2_0.internal.MessageAttributesAccessor;
  import io.opentelemetry.javaagent.bootstrap.http.HttpServerResponseMutator;
  import java.util.Map;
  import org.restlet.Response;
  import org.restlet.util.Series;
  
  public enum RestletResponseMutator implements HttpServerResponseMutator<Response> {
    INSTANCE;
  
    public static final String HEADERS_ATTRIBUTE = "org.restlet.http.headers";
  
    @Override
    public void appendHeader(Response response, String name, String value) {
      Map<String, Object> attributes = MessageAttributesAccessor.getAttributes(response);
      if (attributes == null) {
        // should never happen in practice
        return;
      }
      Series<?> headers = (Series<?>) attributes.get(HEADERS_ATTRIBUTE);
      if (headers == null) {
        headers = MessageAttributesAccessor.createHeaderSeries();
        if (headers == null) {
          // should never happen in practice; abort
          return;
        }
        attributes.put(HEADERS_ATTRIBUTE, headers);
      }
      String existing = headers.getValues(name);
      if (existing != null) {
        value = existing + "," + value;
      }
      MessageAttributesAccessor.setSeriesValue(headers, name, value);
    }
  }
  