//package memoryleak;

import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.concurrent.atomic.AtomicLong;
import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.control.TabPane.TabClosingPolicy;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

public class TabMemoryLeak extends Application {

    public static void main(final String... args) {
        Application.launch(args);
    }

    @Override
    public void start(final Stage stage) throws Exception {
        final BorderPane root = new BorderPane();
        final TabPane tabs = new TabPane();

        tabs.setTabClosingPolicy(TabClosingPolicy.ALL_TABS);
        root.setCenter(tabs);

        final HBox line = new HBox(4);
        createButtons(line, tabs);
        root.setTop(line);

        stage.setScene(new Scene(root, 500, 500));
        stage.show();
    }

    private void createButtons(final HBox line, final TabPane tabs) {

        final Button addTab = new Button("add Tab");
        addTab.setOnAction(e -> tabs.getTabs().add(new MyTab()));
        line.getChildren().add(addTab);

        final Button clearTabs = new Button("clear Tabs");
        clearTabs.setOnAction(e -> tabs.getTabs().clear());
        line.getChildren().add(clearTabs);

        // call GC
        final Button gc = new Button("GC");
        gc.setOnAction(e -> System.gc());
        line.getChildren().add(gc);

        // show tab count
        final Label countTab = new Label();
        line.getChildren().addAll(countTab);
        AnimationTimer timer = new AnimationTimer() {
            @Override
            public void handle(long now) {
                countTab.setText("Tabs: " + MyTab.getCount());
            }
        };
        timer.start();

    }

    static class MyTab extends Tab {

        private static final ArrayList<WeakReference<Tab>> allTabs = new ArrayList<>();
        protected static final AtomicLong ID = new AtomicLong(0);

        private final long id;

        MyTab() {
            super();

            this.id = ID.getAndIncrement();

            setText("Tab " + this.id);
            setId("Tab " + this.id);
            allTabs.add(new WeakReference<>(this));
        }

        static int getCount() {
            int count = 0;
            Iterator<WeakReference<Tab>> it = allTabs.iterator();
            while (it.hasNext()) {
                if (it.next().get() != null) {
                    count++;
                } else {
                    it.remove();
                }
            }
            return count;
        }

    }
}