AsyncTreeModelTest.java

package test;

import com.intellij.icons.AllIcons;
import com.intellij.ide.projectView.PresentationData;
import com.intellij.openapi.Disposable;
import com.intellij.openapi.project.Project;
import com.intellij.openapi.startup.StartupActivity;
import com.intellij.ui.SimpleTextAttributes;
import com.intellij.ui.components.JBScrollPane;
import com.intellij.ui.tree.AsyncTreeModel;
import com.intellij.ui.tree.StructureTreeModel;
import com.intellij.ui.treeStructure.SimpleNode;
import com.intellij.ui.treeStructure.SimpleTreeStructure;
import com.intellij.ui.treeStructure.Tree;
import org.jetbrains.annotations.NotNull;

import javax.swing.*;
import javax.swing.tree.DefaultMutableTreeNode;
import java.awt.*;
import java.util.ArrayList;
import java.util.List;

class AsyncTreeModelTest implements Disposable, StartupActivity {

    private TestSimpleNode root = new TestSimpleNode("First child",
            new TestSimpleNode("Second child 1", new TestSimpleNode("Third child")),
            new TestSimpleNode("Second child 2", new TestSimpleNode("Third child")));

    @Override
    public void runActivity(@NotNull Project project) {
        var treeStructure = new TestSimpleTreeStructure();
        var treeModel = new StructureTreeModel(treeStructure, this);
        var mutableNode = new DefaultMutableTreeNode();
        var tree = new Tree(mutableNode);
        var model = new AsyncTreeModel(treeModel, this);
        tree.setModel(model);
        tree.setRootVisible(false);
        var component = new JPanel(new BorderLayout());
        component.add(new JBScrollPane(tree), "Center");

        JFrame jFrame = new JFrame();
        jFrame.setPreferredSize(new Dimension(500, 500));
        jFrame.add(component);
        jFrame.pack();
        jFrame.setVisible(true);

        new Thread(() -> {
            try {
                Thread.sleep(5000);
            } catch (InterruptedException ignored) {
            }

            root.addChild(new TestSimpleNode("Inserted child"));
            treeModel.invalidate();
        }).start();

    }

    @Override
    public void dispose() {
    }

    public class TestSimpleNode extends SimpleNode {

        private final String text;
        private final List<SimpleNode> children;

        public TestSimpleNode(String text, SimpleNode... children) {
            this.text = text;
            this.children = new ArrayList<>(List.of(children));
        }

        public void addChild(SimpleNode child) {
            this.children.add(child);
        }

        @Override
        protected void update(@NotNull PresentationData presentation) {
            presentation.addText(text, SimpleTextAttributes.GRAYED_ATTRIBUTES);
            presentation.setIcon(AllIcons.Nodes.Method);
        }

        @NotNull
        @Override
        public SimpleNode[] getChildren() {
            return children.toArray(new SimpleNode[0]);
        }
    }

    public class TestSimpleTreeStructure extends SimpleTreeStructure {

        @NotNull
        @Override
        public Object getRootElement() {
            return new TestSimpleNode("Root", root);
        }
    }
}