Depending on what you need to do with the results, you can work with the appropriate return type you configured in the trace parameters. The following types of results may be returned when executing the trace:
-
Elements—Element results provide the utility elements that are found by a trace. Use these results when you need access to individual utility elements, their corresponding features, and their attributes. This is the default trace result type.
-
Geometry—Geometry results contains multipart geometries that represent the union of the geometry for all elements returned. These results are best for displaying the trace result on a map.
-
Functions—A function is a trace configuration that allows you to run calculations on network attributes associated with traced features. A function output is returned for every function defined in the configuration.
// Execute the network utility trace.
ListenableFuture<List<UtilityTraceResult>> utilityTraceResultsListenableFuture =
utilityNetwork.traceAsync(utilityTraceParameters);
// Wait for the trace to complete.
utilityTraceResultsListenableFuture.addDoneListener(() -> {
try {
// Get the trace results.
List<UtilityTraceResult> utilityTraceResults = utilityTraceResultsListenableFuture.get();
// Check that there is a trace result, then get the first result of the utility trace.
if (utilityTraceResults.getFirst() != null &&
utilityTraceResults.getFirst() instanceof UtilityElementTraceResult utilityElementTraceResult) {
// Get the elements in the trace result.
List<UtilityElement> utilityElements = utilityElementTraceResult.getElements();
if (!utilityElements.isEmpty()) {
// Check if there are any elements in the first trace result.
System.out.println("Count of utility elements in first trace result is: "
+ utilityElements.size());
// Process trace results here.
Element results
If you need fine-grained access to the results, such as the ability to work with individual utility elements from the trace, you need to obtain the corresponding features for these elements from the utility element results.
You can use the element's network source to match its table against the layer's table by instance or name.
For every group (network source with utility elements), make sure there is a layer in the map for the features. Next, find the features corresponding to the utility elements.
// (continued from above)
// Make a hash map of key-value pairs where key is the name of a utility network source
// and value is a list of utility elements in that utility network source.
HashMap<String, List<UtilityElement>> hashMap = new HashMap<>();
for (UtilityElement utilityElement : utilityElements) {
// Group together utility elements that have the same network source.
List<UtilityElement> utilityElementsWithSameNetworkSource;
String utilityNetworkSourceName = utilityElement.getNetworkSource().getName();
// If the utility network source name is already a key, then get the
// corresponding list of elements.
if (hashMap.containsKey(utilityNetworkSourceName)) {
utilityElementsWithSameNetworkSource = hashMap.get(utilityNetworkSourceName);
} else {
// If utility network source name is not a key, create a new list of elements.
utilityElementsWithSameNetworkSource = new ArrayList<>();
}
// Add current utility element to the list of elements.
utilityElementsWithSameNetworkSource.add(utilityElement);
// Update the hash map with the new/modified key-value pair.
hashMap.put(utilityNetworkSourceName, utilityElementsWithSameNetworkSource);
}
// Ensure that the features' layer exists in the map.
for (Map.Entry<String, List<UtilityElement>> entry : hashMap.entrySet()) {
FeatureLayer layer = (FeatureLayer) map.getOperationalLayers().getFirst();
if (layer.getFeatureTable().getTableName().equalsIgnoreCase(entry.getKey())) {
// Get the features that correspond to the elements.
ListenableFuture<List<ArcGISFeature>> arcGISFeatureListListenableFuture =
utilityNetwork.fetchFeaturesForElementsAsync(entry.getValue());
arcGISFeatureListListenableFuture.addDoneListener(() -> {
try {
List<ArcGISFeature> arcGISFeatureList = arcGISFeatureListListenableFuture.get();
// Do something with the features.
Select the features that correspond to the trace result or process as required.
// (continued from above)
// Select features to highlight result.
for (ArcGISFeature arcGISFeature : arcGISFeatureList) {
layer.selectFeature(arcGISFeature);
}
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
}); // End of arcGISFeatureListListenableFuture.addDoneListener(() -> {
} // End of if (layer.getFeatureTable().getTableName().equalsIgnoreCase(entry.getKey())) {
} // End of for (Map.Entry<String, List<UtilityElement>> entry : hashMap.entrySet()) {
} else {
System.out.println("First trace result is empty.");
}
} // End of if (utilityTraceResults.getFirst() != null &&
// utilityTraceResults.getFirst() instanceof UtilityElementTraceResult utilityElementTraceResult) {
} catch (Exception e) {
e.printStackTrace();
}
}); // End of utilityTraceResultsListenableFuture.addDoneListener(() -> {
Function results
If function results are included, they will contain a UtilityTraceFunctionOutput
for every UtilityTraceFunction
that was defined in the UtilityTraceConfiguration
. Each UtilityTraceFunctionOutput
contains the original function definition as well as the function result.
Geometry results
Geometry results make it easy to display the trace result as graphics in the map view. At most, geometry results will contain three (multipart) geometries: one multipoint, one polyline, and one polygon. Each geometry represents the union of the geometry of the results of that spatial type. The UtilityGeometryTraceResult
exposes the geometry result for each potential geometry type. If the result does not include a certain geometry type, the corresponding property will be null.
Get the geometry results from the trace results. Depending how the trace parameters were defined (i.e. which result types were requested), there may be more than one result type. Create a new graphic for each geometry in the geometry results, check if there's any need to reproject to the map's spatial reference, use a symbology appropriate for the geometry type, and add them to a graphics overlay in the map view.