How to use co.elastic.apm.agent.impl.context

public void copyFrom(TransactionContext other) {
  response.copyFrom(other.response);
  request.copyFrom(other.request);
  user.copyFrom(other.user);
}

  @Override
  public void resetState() {
    super.resetState();
    custom.clear();
    response.resetState();
    request.resetState();
    user.resetState();
  }
}

public void setUser(String id, String email, String username) {
  if (!isSampled()) {
    return;
  }
  getContext().getUser().withId(id).withEmail(email).withUsername(username);
}

private TransactionContext createContext() {
  TransactionContext context = new TransactionContext();
  Request request = context.getRequest();
  request.withHttpVersion("1.1");
  request.withMethod("POST");
  request.withBodyBuffer().append("Hello World").flip();
  request.getUrl()
    .withProtocol("https")
    .appendToFull("https://www.example.com/p/a/t/h?query=string#hash")
    .withHostname("www.example.com")
    .withPort(8080)
    .withPathname("/p/a/t/h")
    .withSearch("?query=string");
  request.getSocket()
    .withEncrypted(true)
    .withRemoteAddress("12.53.12.1");
  request.addHeader("user-agent", "Mozilla Chrome Edge");
  request.addHeader("content-type", "text/html");
  request.addHeader("cookie", "c1=v1; c2=v2");
  request.addHeader("some-other-header", "foo");
  request.addHeader("array", "foo, bar, baz");
  request.getCookies().add("c1", "v1");
  request.getCookies().add("c2", "v2");
  context.getResponse()
    .withStatusCode(200)
    .withFinished(true)
    .withHeadersSent(true)
    .addHeader("content-type", "application/json");

private void serializeContext(final TransactionContext context) {
  writeFieldName("context");
  jw.writeByte(OBJECT_START);
  if (context.getUser().hasContent()) {
    serializeUser(context.getUser());
    jw.writeByte(COMMA);
  }
  serializeRequest(context.getRequest());
  serializeResponse(context.getResponse());
  // TODO custom context
  writeFieldName("tags");
  final Map<String, String> value = context.getTags();
  serializeTags(value);
  jw.writeByte(OBJECT_END);
  jw.writeByte(COMMA);
}

  private Url newUrl() {
    return new Url()
      .withHostname("localhost")
      .withPathname("/foo")
      .withPort(8080)
      .withProtocol("http")
      .withSearch("foo=bar")
      .appendToFull("http://localhost:8080/foo?foo=bar");
  }
}

public void copyFrom(Request other) {
  this.postParams.copyFrom(other.postParams);
  this.headers.copyFrom(other.headers);
  this.httpVersion = other.httpVersion;
  this.method = other.method;
  this.socket.copyFrom(other.socket);
  this.url.copyFrom(other.url);
  this.cookies.copyFrom(other.cookies);
  if (other.bodyBuffer != null) {
    final CharBuffer otherBuffer = other.getBodyBuffer();
    final CharBuffer thisBuffer = this.withBodyBuffer();
    for (int i = 0; i < otherBuffer.length(); i++) {
      thisBuffer.append(otherBuffer.charAt(i));
    }
    thisBuffer.flip();
  }
}

private void serializeUrl(final Url url) {
  writeFieldName("url");
  jw.writeByte(OBJECT_START);
  writeField("full", url.getFull());
  writeField("hostname", url.getHostname());
  writeField("port", url.getPort());
  writeField("pathname", url.getPathname());
  writeField("search", url.getSearch());
  writeLastField("protocol", url.getProtocol());
  jw.writeByte(OBJECT_END);
  jw.writeByte(COMMA);
}

private Transaction createTransactionWithRequiredValues() {
  Transaction t = new Transaction(mock(ElasticApmTracer.class));
  t.start(TraceContext.asRoot(), null, (long) 0, ConstantSampler.of(true));
  t.withType("type");
  t.getContext().getRequest().withMethod("GET");
  t.getContext().getRequest().getUrl().appendToFull("http://localhost:8080/foo/bar");
  return t;
}

private void serializeUser(final User user) {
  writeFieldName("user");
  jw.writeByte(OBJECT_START);
  writeField("id", user.getId());
  writeField("email", user.getEmail());
  writeLastField("username", user.getUsername());
  jw.writeByte(OBJECT_END);
}

@Test
void testResetState() {
  final Url url = newUrl();
  url.resetState();
  assertThat(toJson(url)).isEqualTo(toJson(new Url()));
}

@Test
void testCopyFrom() {
  TransactionContext context = createContext();
  TransactionContext copyOfContext = new TransactionContext();
  copyOfContext.copyFrom(context);
  assertThat(toJson(context)).isEqualTo(toJson(copyOfContext));
}

@Test
void testCopyOf() {
  final Url url = newUrl();
  final Url copy = new Url();
  copy.copyFrom(url);
  assertThat(toJson(url)).isEqualTo(toJson(copy));
  assertThat(toJson(url)).isNotEqualTo(toJson(new Url()));
}

@Override
public void resetState() {
  postParams.resetState();
  headers.resetState();
  httpVersion = null;
  method = null;
  socket.resetState();
  url.resetState();
  cookies.resetState();
  if (bodyBuffer != null) {
    charBufferPool.recycle(bodyBuffer);
  }
  bodyBuffer = null;
}

@Override
public void addTag(String key, String value) {
  context.getTags().put(key, value);
}

  public boolean hasContent() {
    return method != null ||
      headers.size() > 0 ||
      httpVersion != null ||
      cookies.size() > 0 ||
      postParams.size() > 0 ||
      socket.hasContent() ||
      url.hasContent();
  }
}

@Override
public void addTag(String key, String value) {
  if (!isSampled()) {
    return;
  }
  getContext().getTags().put(key, value);
}

@Override
public void resetState() {
  super.resetState();
  context.resetState();
  stacktrace = null;
  type = null;
  subtype = null;
  action = null;
  originator = null;
}

@Override
public void resetState() {
  super.resetState();
  db.resetState();
  http.resetState();
}

@Override
public void resetState() {
  super.resetState();
  context.resetState();
  result = null;
  spanCount.resetState();
  noop = false;
  type = null;
}