Display a feature layer from a service using the on interaction cache feature request mode.
Use case
ServiceFeatureTable supports three request modes, which define how features are requested from the service and stored in the local table. The feature request modes have different performance characteristics. Use On interaction cache in scenarios with large amounts of infrequently edited data.
How to use the sample
Run the sample and pan and zoom around the map. With each interaction, features will be requested and stored in a local cache. Each subsequent interaction will display features from the cache and only request new features from the service.
How it works
Set the ServiceFeatureTable.FeatureRequestMode property of the service feature table to ON_INTERACTION_CACHE before the table is loaded.
Add the table to the map using a FeatureLayer; features will be requested for the visible extent as the user pans and zooms.
Relevant API
FeatureLayer
ServiceFeatureTable
ServiceFeatureTable.FeatureRequestMode
About the data
The U.S. National Bridge Inventory describes 600,000 bridges in the United States. The sample uses US Bridges, a modified copy of the U.S. National Bridge Inventory hosted on ArcGIS Online. The sample opens with an initial visible extent centered over Bridgeport, CT.
Additional information
On interaction cache is the default feature request mode. Features are requested automatically for the visible extent as the users pans and zooms the map. If the user returns to an area where features have previously been requested, those features won't be requested again.
Tags
cache, feature request mode, performance
Sample Code
ServiceFeatureTableCacheSample.java
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/*
* Copyright 2017 Esri.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/package com.esri.samples.service_feature_table_cache;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import com.esri.arcgisruntime.ArcGISRuntimeEnvironment;
import com.esri.arcgisruntime.data.ServiceFeatureTable;
import com.esri.arcgisruntime.geometry.Envelope;
import com.esri.arcgisruntime.geometry.SpatialReferences;
import com.esri.arcgisruntime.layers.FeatureLayer;
import com.esri.arcgisruntime.loadable.LoadStatus;
import com.esri.arcgisruntime.mapping.ArcGISMap;
import com.esri.arcgisruntime.mapping.BasemapStyle;
import com.esri.arcgisruntime.mapping.Viewpoint;
import com.esri.arcgisruntime.mapping.view.MapView;
publicclassServiceFeatureTableCacheSampleextendsApplication{
private MapView mapView;
private ServiceFeatureTable serviceFeatureTable; // keep loadable in scope to avoid garbage collectionprivatestaticfinal String FEATURE_SERVICE_URL =
"https://services2.arcgis.com/ZQgQTuoyBrtmoGdP/arcgis/rest/services/US_Bridges/FeatureServer/0";
@Overridepublicvoidstart(Stage stage){
try {
// create stack pane and application scene StackPane stackPane = new StackPane();
Scene scene = new Scene(stackPane);
// size the stage, add a title, and set scene to stage stage.setTitle("Service Feature Table Cache Sample");
stage.setWidth(800);
stage.setHeight(700);
stage.setScene(scene);
stage.show();
// authentication with an API key or named user is required to access basemaps and other location services String yourAPIKey = System.getProperty("apiKey");
ArcGISRuntimeEnvironment.setApiKey(yourAPIKey);
// create a map with the light gray basemap style ArcGISMap map = new ArcGISMap(BasemapStyle.ARCGIS_LIGHT_GRAY);
// create a map view and set the map to it mapView = new MapView();
mapView.setMap(map);
// set a viewpoint on the map view mapView.setViewpoint(new Viewpoint(new Envelope(-140.740858094945, 14.1552479740679, -47.693259181055,
64.8874243113506, SpatialReferences.getWgs84())));
// create the service feature table serviceFeatureTable = new ServiceFeatureTable(FEATURE_SERVICE_URL);
// explicitly set the mode to on interaction cache (which is also// the default mode for service feature tables) serviceFeatureTable.setFeatureRequestMode(ServiceFeatureTable.FeatureRequestMode.ON_INTERACTION_CACHE);
// wait for the service feature table to load serviceFeatureTable.loadAsync();
serviceFeatureTable.addDoneLoadingListener(() -> {
if (serviceFeatureTable.getLoadStatus() == LoadStatus.LOADED) {
// create the feature layer using the service feature table FeatureLayer featureLayer = new FeatureLayer(serviceFeatureTable);
// add the feature layer to the map's operational layers map.getOperationalLayers().add(featureLayer);
} else {
new Alert(Alert.AlertType.ERROR, "Error loading Service Feature Table").show();
}
});
// add the map view to stack pane stackPane.getChildren().addAll(mapView);
} catch (Exception e) {
// on any error, display stack trace e.printStackTrace();
}
}
/**
* Stops and releases all resources used in application.
*/@Overridepublicvoidstop(){
// release resources when the application closesif (mapView != null) {
mapView.dispose();
}
}
/**
* Opens and runs application.
*
* @param args arguments passed to this application
*/publicstaticvoidmain(String[] args){
Application.launch(args);
}
}