@Override
  public Map<X509Certificate, List<X509Certificate>> getSignerCertificates(int signersType) {
    SignedContentFactory factory = equinoxContainer.getSignedContentFactory();
    if (factory == null) {
      return Collections.emptyMap();
    }

    try {
      SignerInfo[] infos = signerInfos;
      if (infos == null) {
        SignedContent signedContent = factory.getSignedContent(this);
        infos = signedContent.getSignerInfos();
        signerInfos = infos;
      }
      if (infos.length == 0) return Collections.emptyMap();
      Map<X509Certificate, List<X509Certificate>> results =
          new HashMap<X509Certificate, List<X509Certificate>>(infos.length);
      for (int i = 0; i < infos.length; i++) {
        if (signersType == SIGNERS_TRUSTED && !infos[i].isTrusted()) continue;
        Certificate[] certs = infos[i].getCertificateChain();
        if (certs == null || certs.length == 0) continue;
        List<X509Certificate> certChain = new ArrayList<X509Certificate>();
        for (int j = 0; j < certs.length; j++) certChain.add((X509Certificate) certs[j]);
        results.put((X509Certificate) certs[0], certChain);
      }
      return results;
    } catch (Exception e) {
      return Collections.emptyMap();
    }
  }