/**
* Returns the certificate associated with the given alias.
*
* <p>If the given alias name identifies a <i>trusted certificate entry</i>, the certificate
* associated with that entry is returned. If the given alias name identifies a <i>key entry</i>,
* the first element of the certificate chain of that entry is returned, or null if that entry
* does not have a certificate chain.
*
* @param alias the alias name
* @return the certificate, or null if the given alias does not exist or does not contain a
* certificate.
*/
public Certificate engineGetCertificate(String alias) {
AbstractMap.SimpleEntry<String, Collection<KeyStore>> pair = getKeystoresForReading(alias);
Certificate cert = null;
try {
String entryAlias = pair.getKey();
for (KeyStore keystore : pair.getValue()) {
cert = keystore.getCertificate(entryAlias);
if (cert != null) {
break;
}
}
} catch (KeyStoreException e) {
throw new IllegalStateException(e);
}
return cert;
}
