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.
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ListenableFuture> utilityTraceResultsListenableFuture;
utilityTraceResultsListenableFuture = utilityNetwork.traceAsync(utilityTraceParameters);
utilityTraceResultsListenableFuture.addDoneListener(() -> {
try {
List utilityTraceResults = utilityTraceResultsListenableFuture.get();
if (utilityTraceResults.get(0) != null) {
if (utilityTraceResults.get(0) instanceof UtilityElementTraceResult) {
UtilityElementTraceResult utilityElementTraceResult = (UtilityElementTraceResult) utilityTraceResults.get(0);
List elements = utilityElementTraceResult.getElements();
if (!elements.isEmpty()) {
// check if there are any elements in the first trace result System.out.println("Count of utility elements in first trace result is: " + elements.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.
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// get the first result of the utility trace and then the elements in that resultutilityElementTraceResult = (UtilityElementTraceResult) utilityTraceResults.get(0);
utilityElements = utilityElementTraceResult.getElements();
// group together utility elements that have the same network sourceList utilityElementsWithSameNetworkSource;
if (!utilityElements.isEmpty()) {
// make a HashMap of key-value pairs where key is the name of a UtilityNetworkSource and// value is a list of utility elements in that UtilityNetworkSource HashMap> hashMap = new HashMap<>();
for (UtilityElement utilityElement : utilityElements) {
String utilityNetworkSourceName = utilityElement.getNetworkSource().getName();
// if utilityNetworkSourceName is already a key, get the corresponding list of elementsif (hashMap.containsKey(utilityNetworkSourceName)) {
utilityElementsWithSameNetworkSource = hashMap.get(utilityNetworkSourceName);
}
// if utilityNetworkSourceName is not a key, create a new list of elementselse {
utilityElementsWithSameNetworkSource = new ArrayList<>();
}
// add current utility element to the list of elements utilityElementsWithSameNetworkSource.add(utilityElement);
// update the hashMap with the new/modified key-value pair hashMap.put(utilityNetworkSourceName, utilityElementsWithSameNetworkSource);
}
// ensure that the features' layer exists in the mapfor (Map.Entry> entry : hashMap.entrySet()) {
FeatureLayer layer = (FeatureLayer) map.getOperationalLayers().get(0);
if (layer.getFeatureTable().getTableName().equals(entry.getKey())) {
// get the features that correspond to the elements ListenableFuture> arcGISFeatureListListenableFuture;
arcGISFeatureListListenableFuture = utilityNetwork.fetchFeaturesForElementsAsync(entry.getValue());
arcGISFeatureListListenableFuture.addDoneListener(() -> {
try {
List arcGISFeatureList = arcGISFeatureListListenableFuture.get();
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
});
}
}
} else System.out.println("First trace result is empty");
Select the features that correspond to the trace result or process as required.
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.