private synchronized Set getHostComponents()

in ambari-server/src/main/java/org/apache/ambari/server/controller/AmbariManagementControllerImpl.java [667:792]
108 lines of code
32 McCabe index (conditional complexity)

  private synchronized Set<ServiceComponentHostResponse> getHostComponents(
      ServiceComponentHostRequest request) throws AmbariException {
    if (request.getClusterName() == null
        || request.getClusterName().isEmpty()) {
      throw new IllegalArgumentException("Invalid arguments, cluster name should not be null");
    }

    final Cluster cluster;
    try {
      cluster = clusters.getCluster(request.getClusterName());
    } catch (ClusterNotFoundException e) {
      throw new ParentObjectNotFoundException("Parent Cluster resource doesn't exist", e);
    }

    if (request.getHostname() != null) {
      try {
        if (! clusters.getClustersForHost(request.getHostname()).contains(cluster)) {
          // case where host exists but not associated with given cluster
          throw new ParentObjectNotFoundException("Parent Host resource doesn't exist",
              new HostNotFoundException(request.getClusterName(), request.getHostname()));
        }
      } catch (HostNotFoundException e) {
        // creating new HostNotFoundException to add cluster name
        throw new ParentObjectNotFoundException("Parent Host resource doesn't exist",
            new HostNotFoundException(request.getClusterName(), request.getHostname()));
      }
    }

    if (request.getComponentName() != null) {
      if (request.getServiceName() == null
          || request.getServiceName().isEmpty()) {
        StackId stackId = cluster.getDesiredStackVersion();
        String serviceName =
            ambariMetaInfo.getComponentToService(stackId.getStackName(),
                stackId.getStackVersion(), request.getComponentName());
        if (LOG.isDebugEnabled()) {
          LOG.debug("Looking up service name for component"
              + ", componentName=" + request.getComponentName()
              + ", serviceName=" + serviceName
              + ", stackInfo=" + stackId.getStackId());
        }
        if (serviceName == null
            || serviceName.isEmpty()) {
          throw new ServiceComponentHostNotFoundException(
              cluster.getClusterName(), null, request.getComponentName(),request.getHostname());
        }
        request.setServiceName(serviceName);
      }
    }

    Set<Service> services = new HashSet<Service>();
    if (request.getServiceName() != null && !request.getServiceName().isEmpty()) {
      services.add(cluster.getService(request.getServiceName()));
    } else {
      services.addAll(cluster.getServices().values());
    }

    Set<ServiceComponentHostResponse> response =
        new HashSet<ServiceComponentHostResponse>();

    boolean checkDesiredState = false;
    State desiredStateToCheck = null;
    if (request.getDesiredState() != null
        && !request.getDesiredState().isEmpty()) {
      desiredStateToCheck = State.valueOf(request.getDesiredState());
      if (!desiredStateToCheck.isValidDesiredState()) {
        throw new IllegalArgumentException("Invalid arguments, invalid desired"
            + " state, desiredState=" + desiredStateToCheck);
      }
      checkDesiredState = true;
    }

    for (Service s : services) {
      // filter on component name if provided
      Set<ServiceComponent> components = new HashSet<ServiceComponent>();
      if (request.getComponentName() != null) {
        components.add(s.getServiceComponent(request.getComponentName()));
      } else {
        components.addAll(s.getServiceComponents().values());
      }
      for(ServiceComponent sc : components) {
        if (request.getComponentName() != null) {
          if (!sc.getName().equals(request.getComponentName())) {
            continue;
          }
        }

        // filter on hostname if provided
        // filter on desired state if provided

        if (request.getHostname() != null) {
          try {
            ServiceComponentHost sch = sc.getServiceComponentHost(
                request.getHostname());
            if (checkDesiredState
                && (desiredStateToCheck != sch.getDesiredState())) {
              continue;
            }
            ServiceComponentHostResponse r = sch.convertToResponse();
            response.add(r);
          } catch (ServiceComponentHostNotFoundException e) {
            if (request.getServiceName() != null && request.getComponentName() != null) {
              throw new ServiceComponentHostNotFoundException(cluster.getClusterName(),
                  request.getServiceName(), request.getComponentName(),request.getHostname());
            } else {
              // ignore this since host_component was not specified
              // this is an artifact of how we get host_components and can happen
              // in case where we get all host_components for a host
            }

          }
        } else {
          for (ServiceComponentHost sch :
              sc.getServiceComponentHosts().values()) {
            if (checkDesiredState
                && (desiredStateToCheck != sch.getDesiredState())) {
              continue;
            }
            ServiceComponentHostResponse r = sch.convertToResponse();
            response.add(r);
          }
        }
      }
    }
    return response;
  }