Delete features

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Sample viewer app
Delete features from an online feature service.
Image of delete features feature service
Use case

Sometimes users may want to delete features from an online feature service.
How to use the sample

Click on a feature on the Map, then click the 'delete' button to delete.
How it works

Create and load a ServiceGeodatabase with a feature service URL.
Get the ServiceFeatureTable from the service geodatabase.
Create a FeatureLayer from the service feature table.
Identify the selected feature by using identifyLayerAsync.
Remove the selected features from the ServiceFeatureTable using deleteFeaturesAsync.
Update the data on the server using applyEditsAsync on the ServiceGeodatabase, which will remove the feature from the online service.
Relevant API

Feature
FeatureLayer
ServiceFeatureTable
ServiceGeodatabase
Sample Code

DeleteFeaturesSample.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.delete_features;

import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.stream.Collectors;

import javafx.application.Application;
import javafx.application.Platform;
import javafx.geometry.Insets;
import javafx.geometry.Point2D;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.scene.control.Alert.AlertType;
import javafx.scene.control.Button;
import javafx.scene.input.MouseButton;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

import com.esri.arcgisruntime.ArcGISRuntimeEnvironment;
import com.esri.arcgisruntime.concurrent.ListenableFuture;
import com.esri.arcgisruntime.data.Feature;
import com.esri.arcgisruntime.data.FeatureTableEditResult;
import com.esri.arcgisruntime.data.FeatureQueryResult;
import com.esri.arcgisruntime.data.ServiceFeatureTable;
import com.esri.arcgisruntime.data.ServiceGeodatabase;
import com.esri.arcgisruntime.layers.FeatureLayer;
import com.esri.arcgisruntime.mapping.ArcGISMap;
import com.esri.arcgisruntime.mapping.BasemapStyle;
import com.esri.arcgisruntime.mapping.Viewpoint;
import com.esri.arcgisruntime.mapping.view.IdentifyLayerResult;
import com.esri.arcgisruntime.mapping.view.MapView;

public class DeleteFeaturesSample extends Application {

  private MapView mapView;
  private FeatureLayer featureLayer;
  private ServiceFeatureTable featureTable;
  private Button deleteButton;
  private ListenableFuture<FeatureQueryResult> selectionResult;

  private static final String FEATURE_LAYER_URL =
      "https://sampleserver6.arcgisonline.com/arcgis/rest/services/DamageAssessment/FeatureServer";

  @Override
  public void start(Stage stage) {

    try {
      // create stack pane and application scene
      StackPane stackPane = new StackPane();
      Scene scene = new Scene(stackPane);

      // set title, size, and add scene to stage
      stage.setTitle("Delete Features 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 delete button and fill the width of the screen
      deleteButton = new Button("Delete");
      deleteButton.setMaxWidth(130);
      deleteButton.setDisable(true);

      // create event to delete the selected features on click
      deleteButton.setOnAction(event -> {
        // get selected features
        selectionResult = featureLayer.getSelectedFeaturesAsync();
        selectionResult.addDoneListener(() -> {
          try {
            FeatureQueryResult selected = selectionResult.get();
            // delete selected features
            deleteFeatures(selected, featureTable);
          } catch (InterruptedException | ExecutionException e) {
            displayMessage("Cannot delete features", e.getCause().getMessage());
          }
        });
      });

      // create a map with the streets basemap style
      ArcGISMap map = new ArcGISMap(BasemapStyle.ARCGIS_STREETS);

      // 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(40, -95, 36978595));

      // create a service geodatabase from the service layer url and load it
      var serviceGeodatabase = new ServiceGeodatabase(FEATURE_LAYER_URL);
      serviceGeodatabase.addDoneLoadingListener(() -> {

        // create a service feature table from the first layer on the service geodatabase's table
        featureTable = serviceGeodatabase.getTable(0);

        // create a feature layer from the feature table
        featureLayer = new FeatureLayer(featureTable);

        // add the layer to the ArcGISMap
        map.getOperationalLayers().add(featureLayer);
      });
      serviceGeodatabase.loadAsync();

      mapView.setOnMouseClicked(event -> {
        // check for primary or secondary mouse click
        if (event.isStillSincePress() && event.getButton() == MouseButton.PRIMARY) {
          // create a point from where the user clicked
          Point2D point = new Point2D(event.getX(), event.getY());

          // clear any previous selection
          featureLayer.clearSelection();
          deleteButton.setDisable(true);

          // identify the clicked feature
          ListenableFuture<IdentifyLayerResult> results = mapView.identifyLayerAsync(featureLayer, point, 1, false);
          results.addDoneListener(() -> {
            try {
              IdentifyLayerResult layer = results.get();
              if (!layer.getElements().isEmpty()) {
                // search the layers for identified features
                List<Feature> features = layer.getElements()
                  .stream()
                  .filter(g -> g instanceof Feature)
                  .map(g -> (Feature) g)
                  .collect(Collectors.toList());
                // add the clicked feature to the selection
                if (features.size() > 0) {
                  featureLayer.selectFeatures(features);
                  deleteButton.setDisable(false);
                }
              }
            } catch (InterruptedException | ExecutionException e) {
              displayMessage("Exception getting identify result", e.getCause().getMessage());
            }
          });
        }
      });

      // add the map view and control box to stack pane
      stackPane.getChildren().addAll(mapView, deleteButton);
      StackPane.setAlignment(deleteButton, Pos.TOP_LEFT);
      StackPane.setMargin(deleteButton, new Insets(10, 0, 0, 10));

    } catch (Exception e) {
      // on any error, display the stack trace
      e.printStackTrace();
    }
  }

  /**
   * Deletes features from a ServiceFeatureTable and applies the changes to the
   * server.
   */
  private void deleteFeatures(FeatureQueryResult features, ServiceFeatureTable featureTable) {

    // delete feature from the feature table and apply edit to server
    featureTable.deleteFeaturesAsync(features).addDoneListener(() -> applyEdits(featureTable));
  }

  /**
   * Sends any edits on the ServiceFeatureTable to the server.
   *
   * @param featureTable service feature table
   */
  private void applyEdits(ServiceFeatureTable featureTable) {

    // apply the changes to the server
    ListenableFuture<List<FeatureTableEditResult>> editResult = featureTable.getServiceGeodatabase().applyEditsAsync();
    editResult.addDoneListener(() -> {
      try {
        List<FeatureTableEditResult> edits = editResult.get();
        // check if the server edit was successful
        if (edits != null && edits.size() > 0) {
          var featureEditResult = edits.get(0).getEditResult().get(0);
          if (!featureEditResult.hasCompletedWithErrors()) {
            displayMessage(null, "Feature successfully deleted");
            deleteButton.setDisable(true);
          } else {
            throw featureEditResult.getError();
          }
        }
      } catch (InterruptedException | ExecutionException e) {
        displayMessage("Exception applying edits on server", e.getCause().getMessage());
      }
    });
  }

  /**
   * Shows a message in an alert dialog.
   *
   * @param title title of alert
   * @param message message to display
   */
  private void displayMessage(String title, String message) {

    Platform.runLater(() -> {
      Alert dialog = new Alert(AlertType.INFORMATION);
      dialog.initOwner(mapView.getScene().getWindow());
      dialog.setHeaderText(title);
      dialog.setContentText(message);
      dialog.showAndWait();
    });
  }

  /**
   * Stops and releases all resources used in application.
   */
  @Override
  public void stop() {

    if (mapView != null) {
      mapView.dispose();
    }
  }

  /**
   * Opens and runs application.
   *
   * @param args arguments passed to this application
   */
  public static void main(String[] args) {

    Application.launch(args);
  }

}