Develop Reference

Netbeans IDE "stops working" apprently after creating new ActionTimer, ChangeListener

#Override
public void start(Stage stage) {
// The class Random is used to randomize the dice rolls
Random random = new Random();
NumberAxis xAxis = new NumberAxis();
// y-axes represents the average of the rolls. The average is always between [1-6]
NumberAxis yAxis = new NumberAxis(1, 6, 1);
LineChart<Number, Number> lineChart = new LineChart<>(xAxis, yAxis);
// removing elements of the chart, e.g. circles on points
lineChart.setLegendVisible(false);
lineChart.setAnimated(false);
lineChart.setCreateSymbols(false);
// we create a variable representing the data and add it to the chart
XYChart.Series average = new XYChart.Series();
lineChart.getData().add(average);
new AnimationTimer() {
private long previous;
private long sum;
private long count;
#Override
public void handle(long current) {
if (current - previous < 100_000_000L) {
return;
}
previous = current;
// roll the dice
int number = random.nextInt(6) + 1;
// we grow the sum and increment the count
sum += number;
count++;
// we add a new data point to the chart
average.getData().add(new XYChart.Data(count, 1.0 * sum / count));
}
}.start();
Scene scene = new Scene(lineChart, 400, 300);
stage.setScene(scene);
stage.show();
}
I am doing the mooc.fi Java course, right now at part 14, and there was an example code I wanted to try out. This is the problematic part of the code.
When I paste this into the DiceRolling class (that extends Application) above the main method, the IDE loses all its functionalities. What it means is that Ctrl+Space shows no suggestion nowhere in the code, if I select part of the code with mouse I cannot Ctrl+X it out, stops checking if the code has mistakes in it (talking about the red underline), and it just overall stops checking the code. I could narrow the reason down to the new ActionTimer part of the code. The problem occurs only after the first curly bracket is written there.
I have experienced this problem earlier, at that time I was creating a new ChangeListener inside a lambda expression and the first curly bracket caused the problem there too. I have no idea why it happens, or if it has a meaning or it's just a bug.

How to speed up drawing graphs (charts) in Java? (own library)

How to write a java library that would display graphs (charts) with large datasets (100-200 thousand points)? I think that such a large graph does not need to be displayed entirely, I probably only need to display a part of it, for example, a thousand points. But I need to be able to move around the graph and scale it.
It is also necessary that the charts are built in real time. As I understand it, for any action with the chart, the data must be displayed again, that is, thereby updated.
Maybe for speed it will be possible to do parallel execution of some parts of the code for drawing the chart. Because the speed of execution will be the main thing in this library.
I also plan to convert the chart to svg to be inserted into the html page.
Now I just build a graph using JavaFX, and it is very slow to build on a couple of thousand points and JavaFX does not seem to have tools for scaling.
public class FXLineChart {
private List<Long> dataset;
public FXLineChart(List<Long> dataset) {
this.dataset = dataset;
}
public void drawChart(Stage stage) {
stage.setTitle("Chart");
final NumberAxis xAxis = new NumberAxis();
final NumberAxis yAxis = new NumberAxis();
final LineChart<Number, Number> lineChart =
new LineChart<Number, Number>(xAxis, yAxis);
lineChart.setTitle("Check dataset");
XYChart.Series series = new XYChart.Series();
for (int i = 0; i < dataset.size(); i++) {
series.getData().add(new XYChart.Data(i, dataset.get(i)));
}
lineChart.getData().add(series);
Scene scene = new Scene(lineChart, 800, 600);
stage.setScene(scene);
stage.show();
}
}
JFreeChart is slightly better, but the chart slows down at several tens of thousands of points. I did not find information about real time in JFreeChart.
Maybe someone has a code for a similar task or idea? The challenge is that according to the assignment it should be its own library.

JavaFX Chart - space between legends [duplicate]

This question already has an answer here:
Fix spacing between different series in JavaFX line chart
(1 answer)
Closed 3 years ago.
I have this code:
public static void main(String[] args){ launch(args); }
#Override
public void start(Stage primaryStage){
NumberAxis xAxis = new NumberAxis(0, 23, 1);
xAxis.setLabel("XX");
NumberAxis yAxis = new NumberAxis();
yAxis.setLabel("YY");
LineChart<Number, Number> lineChart = new LineChart<>(xAxis, yAxis);
XYChart.Series<Number, Number> series1 = new XYChart.Series<>();
series1.setName("Loooooooooooooongest");
XYChart.Series<Number, Number> series2 = new XYChart.Series<>();
series2.setName("Short");
XYChart.Series<Number, Number> series3 = new XYChart.Series<>();
series3.setName("Loooooong");
lineChart.getData().addAll(series1, series2, series3);
primaryStage.setScene(new Scene(lineChart));
primaryStage.sizeToScene();
primaryStage.centerOnScreen();
primaryStage.show();
}
It looks like this:
Every legend has allocated space like the longest legend.
How I can remove all that space?

You can probably use a CSS Property. Maybe something like -fx-padding or -fx-margin. Not sure right now.
This could give you a good idea about for using CSS Properties in JavaFX: How to set specific color to JavaFX XYChart.Series?
Also it's a great idea to use the JavaFX-SceneBuilder. You can apply CSS there and directly see what it does.

Prefuse : Organizing edges for clarity

I'm working on my personal family tree in Java/Eclipse, and happily bumped into prefuse as for graphic representation.
So far the result looks adaquate in regard to my database feed, but I'm still missing key points to make it easier to browse.
Point 1: verteces represent either a person or a union, and my graph is directed from older to younger members. This is reflected by the arrows on the edges. Yet I'd love to group the arrows in 1 direction only (I'm trying to group generations together if you like), but I can't start to find how to do that. For information, I'm using the NodeLinkTreeLayout as of now.
Point 2: aside from the graph itself, my app main window contains a second JPanel where I would like to modify / insert members. So I want to add an action to each node to call the procedures in the second JPanel. My research on how to access a java class from a node are inconclusive so far, it seems that all the examples from the starter prefuse pack are only based on graph interaction.
There it is. You might already have understood that I'm very new to prefuse and not a pro in Java. So any comment / directions / advice would really be appreciated. I will add a screecap and my graph code so you can see what could be done better.
Thank you for your time, and looking forward to reading your insights.
yorran
public class ShowGraph extends Display {
public static final String EDGES = "graph.edges";
public ShowGraph() {
super(new Visualization());
Graph mG = FamGraph.getGraph();
m_vis.addGraph("graph", mG);
m_vis.setInteractive("graphe.edges", null, false);
m_vis.setValue("graph.nodes", null, VisualItem.SHAPE, new Integer(Constants.SHAPE_ELLIPSE));
EdgeRenderer edgeR = new EdgeRenderer(Constants.EDGE_TYPE_CURVE, Constants.EDGE_ARROW_FORWARD);
LabelRenderer nodeR = new LabelRenderer("name");
nodeR.setRoundedCorner(8, 8);
nodeR.setHorizontalAlignment(Constants.LEFT);
DefaultRendererFactory drf = new DefaultRendererFactory();
drf.setDefaultRenderer(nodeR);
drf.setDefaultEdgeRenderer(edgeR);
m_vis.setRendererFactory(drf);
int[] palette = new int[] {
ColorLib.rgb(255, 180, 180), ColorLib.rgb(190, 190, 255)
};
DataColorAction nFill = new DataColorAction("graph.nodes", "label", Constants.NOMINAL, VisualItem.FILLCOLOR, palette);
ColorAction edges = new ColorAction("graph.edges", VisualItem.STROKECOLOR, ColorLib.gray(230));
ColorAction arrow = new ColorAction("graph.edges", VisualItem.FILLCOLOR, ColorLib.gray(230));
ColorAction text = new ColorAction("graph.nodes", VisualItem.TEXTCOLOR, ColorLib.gray(0));
ActionList color = new ActionList();
color.add(nFill);
color.add(edges);
color.add(arrow);
color.add(text);
ActionList layout = new ActionList(Activity.INFINITY);
//layout.add(new ForceDirectedLayout("graph", true));
layout.add(new NodeLinkTreeLayout("graph"));
layout.add(new RepaintAction());
m_vis.putAction("color", color);
m_vis.putAction("layout", layout);
setSize(1200, 900); //size controlled by parent jpanel - Comment out after tests
pan(360, 250);
setHighQuality(true);
addControlListener(new DragControl());
addControlListener(new PanControl());
addControlListener(new ZoomControl());
addControlListener(new ZoomToFitControl());
m_vis.run("color");
m_vis.run("layout");
}
public static void main(String[] args) {
Fulltree.fireUp();
ShowGraph mG = new ShowGraph();
JFrame frame = new JFrame("My family chart");
JPanel thePanel = new JPanel();
frame.getContentPane().add(thePanel);
thePanel.add(mG);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}

So after a lot of reseach, I'm answering to my own questions in case someone meets the same issues :
as for point 1 : ForceDirectedGraph is a lot better than NodeLinkTreeLayout, especially when your graph starts counting many members. Family branches make a lot more sense than viewing generations aligned.
as for point 2 : node related actions are the way to go, through a ControlListener:
addControlListener(new ControlAdapter() {
public void itemClicked(VisualItem item, MouseEvent e) {
// anything you need here
// even filter right and left click for a sub menu
}
});
One more thing : if you add actions to your graph (search, predicates...), make sure to stop them if you need to rebuild your graph at some point. If you don't, your actions will generate errors you will spend hours (if not days) to debug.

Live-Update LineChart in JavaFX

I have problem with updating JavaFX UI - I want to update line chart and some labels on my scene when it's already shown.
My task is to do some calculations (calling function in other class which returns dataseries) and add updated series to the chart.
The following code (which is in a loop) may present what i want to do:
//double x - x value of the point i want to add to my chart
//double y - y value of the point i want to add to my chart
//string s - some result from function
mySeries.getData().add(new XYChart.Data(x, y));
someLabel.setText(s);
My program freezes and give only final solution after some time, but i want to see the points on the chart exactly after they're added, not at the end of the execution. If the process is too quick, i would like to add Thread.sleep(1000) before adding the next point to the chart.
I know it has something to do with threads, concurrency and tasks, but i wasn't able to find a solution yet. I tried to use some code I found here but still I don't know the correct answer.

Every user action, e.g. click a button, will notify your action listener within the UI thread. Logic in the UI thread should be as fast as possible. I think you are reacting on a user event and then execute a long running task in the UI thread. Try to put your code in a background thread. Further you need to put the UI updates back again in the UI thread. You can do this with "Platform.runLater(...)".
Something like this:
public class Test extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception {
Scene scene = new Scene(createChart());
primaryStage.setScene(scene);
primaryStage.setHeight(800);
primaryStage.setWidth(1200);
primaryStage.show();
}
private Parent createChart() {
LineChart<Number, Number> lc = new LineChart<>(new NumberAxis(), new NumberAxis());
XYChart.Series<Number, Number> series = new XYChart.Series<>();
lc.getData().add(series);
new Thread(() -> {
try {
Thread.sleep(5000);
for (int i = 0; i < 15; i++) {
int finalI = i;
Platform.runLater(() -> series.getData().add(new XYChart.Data<>(1 + finalI, 1 + finalI)));
Thread.sleep(1000);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
return lc;
}
}