public List create()

in gateway-discovery-ambari/src/main/java/org/apache/knox/gateway/topology/discovery/ambari/HDFSURLCreatorBase.java [56:133]
58 lines of code
17 McCabe index (conditional complexity)

  public List<String> create(String service, Map<String, String> serviceParams) {
    List<String> urls = new ArrayList<>();

    if (getTargetService().equals(service)) {
      AmbariCluster.ServiceConfiguration sc =
                                      cluster.getServiceConfiguration(CONFIG_SERVICE_HDFS, CONFIG_TYPE_HDFS_SITE);
      if (sc != null) {
        // First, check if it's HA config
        String nameServices = sc.getProperties().get("dfs.nameservices");
        if (nameServices != null && !nameServices.isEmpty()) {
          String ns = null;

          // Parse the nameservices value
          String[] namespaces = nameServices.split(",");

          String nsParam = (serviceParams != null) ? serviceParams.get(NAMESERVICE_PARAM) : null;

          if (namespaces.length > 1 || nsParam != null) {
            if (nsParam != null) {
              if (!validateDeclaredNameService(namespaces, nsParam)) {
                log.undefinedHDFSNameService(nsParam);
              }
              ns = nsParam;
            } else {
              // core-site.xml : dfs.defaultFS property (e.g., hdfs://ns1)
              AmbariCluster.ServiceConfiguration coreSite =
                                        cluster.getServiceConfiguration(CONFIG_SERVICE_HDFS, CONFIG_TYPE_CORE_SITE);
              if (coreSite != null) {
                String defaultFS = coreSite.getProperties().get("fs.defaultFS");
                if (defaultFS != null) {
                  ns = defaultFS.substring(defaultFS.lastIndexOf('/') + 1);
                }
              }
            }
          }

          // If only a single namespace, or no namespace specified and no default configured, use the first in the "list"
          if (ns == null) {
            ns = namespaces[0];
          }

          // If it is an HA configuration
          Map<String, String> props = sc.getProperties();

          // More recent HDFS configurations support a property enumerating the node names associated with a
          // nameservice. If this property is present, use its value to create the correct URLs.
          String nameServiceNodes = props.get("dfs.ha.namenodes." + ns);
          if (nameServiceNodes != null) {
            String addressPropertyPrefix = getAddressPropertyPrefix();
            String[] nodes = nameServiceNodes.split(",");
            for (String node : nodes) {
              String propertyValue = getHANameNodeHttpAddress(addressPropertyPrefix, props, ns, node);
              if (propertyValue != null) {
                urls.add(createURL(propertyValue));
              }
            }
          } else {
            // Name node HTTP[S] addresses are defined as properties of the form:
            //      dfs.namenode.http[s]-address.<NAMESERVICE>.nn<INDEX>
            // So, this iterates over the nn<INDEX> properties until there is no such property (since it cannot be
            // known how many are defined by any other means).
            String addressPropertyPrefix = getAddressPropertyPrefix();
            int i = 1;
            String propertyValue = getHANameNodeHttpAddress(addressPropertyPrefix, props, ns, i++);
            while (propertyValue != null) {
              urls.add(createURL(propertyValue));
              propertyValue = getHANameNodeHttpAddress(addressPropertyPrefix, props, ns, i++);
            }
          }

        } else { // If it's not an HA configuration, get the single name node HTTP[S] address
          urls.add(createURL(sc.getProperties().get(getAddressPropertyPrefix())));
        }
      }
    }

    return urls;
  }