protected String getEncryptionKeyProviderUri() {
    //If KMS is configured, this value will not be empty
    String encryptionKeyProviderUri = getProperty("hdfs-site", "dfs.encryption.key.provider.uri");
    return encryptionKeyProviderUri;
  }
takes context and any extra custom properties that needs to be included into config
@param context
@param customProperties
contrib/views/utils/src/main/java/org/apache/ambari/view/utils/hdfs/ConfigurationBuilder.java