JavaFX Service example

ServiceTest.java

import javafx.animation.*;
import javafx.application.Application;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.collections.*;
import javafx.concurrent.*;
import javafx.event.*;
import javafx.geometry.*;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.effect.*;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.*;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;
import javafx.util.Duration;
 
public class ServiceTest extends Application {
  public static void main(String[] args) throws Exception { launch(args); }
  public void start(final Stage stage) throws Exception {
    // set up some controls.
    final Label statusLabel = new Label();
    final Label celebrateLabel = new Label();
    final Button searchButton = new Button("Search");
    searchButton.setTooltip(new Tooltip("Look for friends"));
    final ListView<String> peopleView = new ListView<String>();
    peopleView.setMaxHeight(Double.MAX_VALUE);
    peopleView.setTooltip(new Tooltip("Friends we find are displayed here"));
    final ProgressBar progressBar = new ProgressBar();
    progressBar.prefWidthProperty().bind(peopleView.widthProperty());
 
    // create a service.
    final Service friendFinder = new Service<ObservableList<String>>() {
      @Override protected Task createTask() {
        return new Task<ObservableList<String>>() {
          @Override protected ObservableList<String> call() throws InterruptedException {
            updateMessage("Finding friends . . .");
            updateProgress(0, 10);
            for (int i = 0; i < 10; i++) {
              Thread.sleep(300);
              updateProgress(i + 1, 10);
            }
            updateMessage("Found them.");
            return FXCollections.observableArrayList("John", "Jim", "Geoff", "Jill", "Suki", "Chiang", "Lin");
          }
        };
      }
    };
 
    // bind interesting service properties to the controls.
    statusLabel.textProperty().bind(friendFinder.messageProperty());
    searchButton.disableProperty().bind(friendFinder.runningProperty());
    peopleView.itemsProperty().bind(friendFinder.valueProperty());
    progressBar.progressProperty().bind(friendFinder.progressProperty());
    progressBar.visibleProperty().bind(friendFinder.progressProperty().isNotEqualTo(new SimpleDoubleProperty(ProgressBar.INDETERMINATE_PROGRESS)));
 
    // kick off the service on an action.
    searchButton.setOnAction(new EventHandler<ActionEvent>() {
      @Override public void handle(ActionEvent actionEvent) {
        if (!friendFinder.isRunning()) {
          friendFinder.reset();
          friendFinder.start();
        }
      }
    });
 
    // create a distracting square with different colors for different states.
    final Color normalDistractorColor = Color.BURLYWOOD;
    final Color runningDistractorColor = Color.DARKGREEN;
    final Color highlightedDistractorColor = Color.FIREBRICK;
    final Rectangle distractor = new Rectangle(25, 25, normalDistractorColor);
    distractor.setUserData(false); // maintains whether or not the mouse is in the distractor.
    distractor.setOpacity(0.8);
    Tooltip.install(distractor, new Tooltip("If you are looking for friends, you can click on me to stop searching"));
 
    // rotate the distractor to show that animation and stuff still continues while the work is being done.
    RotateTransition rt = new RotateTransition(Duration.millis(3000), distractor);
    rt.setByAngle(360);
    rt.setCycleCount(Animation.INDEFINITE);
    rt.setInterpolator(Interpolator.LINEAR);
    rt.play();
 
    // create some effects for the animation.
    final BoxBlur normal      = new BoxBlur();
    final BoxBlur highlighted = new BoxBlur(); highlighted.setInput(new DropShadow());
    distractor.setEffect(normal);
 
    // the distracting animation can be used to cancel the friend lookup.
    distractor.setOnMouseClicked(new EventHandler<MouseEvent>() {
      @Override public void handle(MouseEvent mouseEvent) {
        if (friendFinder.isRunning()) {
          friendFinder.cancel();
        }
      }
    });
    distractor.setOnMouseEntered(new EventHandler<MouseEvent>() {
      @Override public void handle(MouseEvent mouseEvent) {
        distractor.setUserData(true);
        if (friendFinder.isRunning()) {
          distractor.setEffect(highlighted);
          distractor.setFill(highlightedDistractorColor);
        }
      }
    });
    distractor.setOnMouseExited(new EventHandler<MouseEvent>() {
      @Override public void handle(MouseEvent mouseEvent) {
        distractor.setUserData(false);
        distractor.setEffect(normal);
        distractor.setFill(normalDistractorColor);
      }
    });
 
    // do something when the service has succeeded.
    friendFinder.stateProperty().addListener(new ChangeListener<Worker.State>() {
      @Override public void changed(ObservableValue<? extends Worker.State> observableValue, Worker.State oldState, Worker.State newState) {
        switch (newState) {
          case SCHEDULED:
            celebrateLabel.setVisible(false);
            progressBar.progressProperty().bind(friendFinder.progressProperty());  // workaround, we should be able to permanently bind to the progress, but unless we do this sometimes the progress does not always reach the end.
            break;
          case READY:
          case RUNNING:
            celebrateLabel.setVisible(false);
            break;
          case SUCCEEDED:
            celebrateLabel.setVisible(true);
            celebrateLabel.setText("Let's grab a beer.");
            progressBar.progressProperty().unbind();
            progressBar.setProgress(1);  // workaround, we should be able to permanently bind to the progress, but unless we do this sometimes the progress does not always reach the end. (even this workaround didn't work, so I have no idea about this...)
            break;
          case CANCELLED:
          case FAILED:
            celebrateLabel.setVisible(true);
            celebrateLabel.setText("Bummer dude, party's over.");
            break;
        }
      }
    });
 
    // maintain the distractor colors while the service is running.
    friendFinder.runningProperty().addListener(new ChangeListener<Boolean>() {
      @Override public void changed(ObservableValue<? extends Boolean> observableValue, Boolean aBoolean, Boolean isRunning) {
        if (isRunning) {
          if (!(Boolean) distractor.getUserData()) {
            distractor.setEffect(normal);
            distractor.setFill(runningDistractorColor);
          } else {
            distractor.setEffect(highlighted);
            distractor.setFill(highlightedDistractorColor);
          }
        } else {
          distractor.setEffect(normal);
          distractor.setFill(normalDistractorColor);
        }
      }
    });
 
    // layout the scene.
    stage.setTitle("Friend Finder");
    VBox.setVgrow(peopleView, Priority.ALWAYS);
    HBox.setMargin(statusLabel, new Insets(3, 0, 0, 0));     // workaround because setting HBox alignment BASELINE_LEFT causes layout glitches.
    HBox.setMargin(celebrateLabel, new Insets(3, 0, 0, 0));  // workaround because setting HBox alignment BASELINE_LEFT causes layout glitches.
    HBox.setHgrow(statusLabel, Priority.SOMETIMES);
    StackPane.setAlignment(distractor, Pos.TOP_RIGHT);
    final Pane layout =
      StackPaneBuilder.create().alignment(Pos.TOP_RIGHT).children(
        VBoxBuilder.create().spacing(8).children(
          VBoxBuilder.create().spacing(5).children(
            HBoxBuilder.create().spacing(10).children(
              searchButton,
              statusLabel,
              celebrateLabel
            ).build(),
            progressBar
          ).build(),
          peopleView
        ).build(),
        distractor
      ).build();
    layout.setStyle("-fx-background-color: cornsilk; -fx-padding:10; -fx-font-size: 16;");
    Scene scene = new Scene(layout, 480, 360);
    stage.setScene(scene);
    stage.show();
  }
}