Add initial draft of TreeTable.

core/src/main/java/com/github/weisj/darklaf/components/treetable/DefaultTreeTableCellRenderer.java

@@ -0,0 +1,121 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable;
+
+import java.awt.*;
+
+import javax.swing.*;
+import javax.swing.table.TableCellRenderer;
+import javax.swing.tree.TreeModel;
+import javax.swing.tree.TreePath;
+
+import com.github.weisj.darklaf.ui.tree.DarkTreeUI;
+import com.github.weisj.darklaf.util.DarkUIUtil;
+
+public class DefaultTreeTableCellRenderer extends JComponent implements TableCellRenderer {
+
+    private final JTreeTable treeTable;
+    private final RendererTree rendererTree = new RendererTree();
+    private int paintingRow;
+
+    public DefaultTreeTableCellRenderer(final JTreeTable treeTable, final TreeModel model) {
+        this.treeTable = treeTable;
+        rendererTree.setRowHeight(rendererTree.getRowHeight());
+        rendererTree.setModel(model);
+        rendererTree.setBounds(0, 0, Integer.MAX_VALUE, Integer.MAX_VALUE);
+    }
+
+    @Override
+    protected void paintComponent(final Graphics g) {
+        DarkTreeUI ui = DarkUIUtil.getUIOfType(rendererTree.getUI(), DarkTreeUI.class);
+        if (ui != null) {
+            ui.paintRow(g, paintingRow);
+        }
+    }
+
+    public Component getTableCellRendererComponent(final JTable table, final Object value, final boolean isSelected,
+                                                   final boolean hasFocus, final int row, final int column) {
+        paintingRow = row;
+        rendererTree.setFocus(hasFocus || table.hasFocus());
+        rendererTree.setSelectable(!hasFocus);
+        return this;
+    }
+
+    public TreeTableTree getTree() {
+        return rendererTree;
+    }
+
+    protected class RendererTree extends TreeTableTree {
+        private boolean focus;
+        private boolean selectable;
+
+        public void setRowHeight(final int rowHeight) {
+            if (rowHeight > 0) {
+                super.setRowHeight(rowHeight);
+                if (treeTable != null && treeTable.getRowHeight() != rowHeight) {
+                    treeTable.setRowHeight(getRowHeight());
+                }
+            }
+        }
+
+        @Override
+        public void repaint(final int x, final int y, final int width, final int height) {
+            treeTable.repaint(x, y, treeTable.getColumnModel().getColumn(0).getWidth(), height);
+        }
+
+        @Override
+        public boolean isRowSelected(final int row) {
+            return selectable && super.isRowSelected(row);
+        }
+
+        @Override
+        public boolean isPathSelected(final TreePath path) {
+            return selectable && super.isPathSelected(path);
+        }
+
+        @Override
+        public void scrollRectToVisible(final Rectangle aRect) {
+            treeTable.scrollRectToVisible(aRect);
+        }
+
+        public void setFocus(final boolean focus) {
+            this.focus = focus;
+        }
+
+        public void setSelectable(final boolean selectable) {
+            this.selectable = selectable;
+        }
+
+        @Override
+        public boolean hasFocus() {
+            return focus;
+        }
+
+        @Override
+        public boolean isFocusOwner() {
+            return super.hasFocus();
+        }
+    }
+}

core/src/main/java/com/github/weisj/darklaf/components/treetable/JTreeTable.java

@@ -0,0 +1,106 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable;
+
+import java.awt.*;
+import java.awt.event.InputEvent;
+import java.awt.event.KeyEvent;
+
+import javax.swing.*;
+import javax.swing.event.TreeSelectionEvent;
+import javax.swing.event.TreeSelectionListener;
+
+import com.github.weisj.darklaf.components.treetable.model.AbstractTreeTableModel;
+import com.github.weisj.darklaf.components.treetable.model.DefaultTreeTableSelectionModel;
+import com.github.weisj.darklaf.components.treetable.model.TreeTableModel;
+import com.github.weisj.darklaf.ui.cell.hint.CellHintPopupListener;
+import com.github.weisj.darklaf.ui.tree.DarkTreeUI;
+import com.github.weisj.darklaf.util.DarkUIUtil;
+
+public class JTreeTable extends JTable implements TreeSelectionListener {
+
+    private final TreeTableTree tree;
+
+    public JTreeTable(final AbstractTreeTableModel treeTableModel) {
+        DefaultTreeTableCellRenderer treeCellRenderer = new DefaultTreeTableCellRenderer(this, treeTableModel);
+        tree = treeCellRenderer.getTree();
+
+        add(tree);
+
+        tree.putClientProperty(DarkTreeUI.KEY_IS_TABLE_TREE, true);
+
+        DefaultTreeTableSelectionModel selectionModel = new DefaultTreeTableSelectionModel(tree);
+        tree.setSelectionModel(selectionModel);
+        setSelectionModel(selectionModel);
+        tree.addTreeSelectionListener(this);
+
+        setDefaultRenderer(TreeTableModel.class, treeCellRenderer);
+        super.setModel(new TreeTableModelAdapter(treeTableModel, tree));
+        setShowHorizontalLines(false);
+    }
+
+    @Override
+    public void doLayout() {
+        super.doLayout();
+        int grid = getShowVerticalLines() ? getIntercellSpacing().width : 0;
+        tree.setBounds(0, 0, getColumnModel().getColumn(0).getWidth() - grid, getHeight());
+    }
+
+    @Override
+    public void repaint(final Rectangle r) {
+        super.repaint(r);
+        SwingUtilities.invokeLater(() -> {
+            DarkTreeUI ui = DarkUIUtil.getUIOfType(tree.getUI(), DarkTreeUI.class);
+            if (ui != null) {
+                CellHintPopupListener<JTree, ?> listener = ui.getPopupListener();
+                if (listener != null) listener.repaint();
+            }
+        });
+    }
+
+    @Override
+    public int getComponentCount() {
+        return 0;
+    }
+
+    @Override
+    protected void processEvent(final AWTEvent e) {
+        if (e instanceof InputEvent) {
+            if (e instanceof KeyEvent) {
+                if (getColumnModel().getSelectionModel().getLeadSelectionIndex() == 0
+                    && !((KeyEvent) e).isShiftDown()) {
+                    tree.processEvent(e);
+                }
+            }
+            if (((InputEvent) e).isConsumed()) return;
+        }
+        super.processEvent(e);
+    }
+
+    @Override
+    public void valueChanged(final TreeSelectionEvent e) {
+        repaint(0, 0, getColumnModel().getColumn(0).getWidth(), getHeight());
+    }
+}

core/src/main/java/com/github/weisj/darklaf/components/treetable/TreeTableModelAdapter.java

@@ -0,0 +1,103 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable;
+
+import javax.swing.*;
+import javax.swing.event.TreeExpansionEvent;
+import javax.swing.event.TreeExpansionListener;
+import javax.swing.table.AbstractTableModel;
+import javax.swing.tree.TreeNode;
+import javax.swing.tree.TreePath;
+
+import com.github.weisj.darklaf.components.treetable.model.TreeTableModel;
+
+public class TreeTableModelAdapter extends AbstractTableModel {
+
+    private final JTree tree;
+    private final TreeTableModel treeTableModel;
+
+    public TreeTableModelAdapter(final TreeTableModel treeTableModel, final JTree tree) {
+        this.tree = tree;
+        this.treeTableModel = treeTableModel;
+
+        tree.addTreeExpansionListener(new TreeExpansionListener() {
+            public void treeExpanded(final TreeExpansionEvent event) {
+                TreePath path = event.getPath();
+                int start = tree.getRowForPath(path);
+                int length = ((TreeNode) path.getLastPathComponent()).getChildCount();
+                int selection = tree.getLeadSelectionRow();
+                fireTableRowsInserted(start, start + length);
+                tree.setSelectionRow(selection);
+            }
+
+            public void treeCollapsed(final TreeExpansionEvent event) {
+                TreePath path = event.getPath();
+                int start = tree.getRowForPath(path);
+                int length = ((TreeNode) path.getLastPathComponent()).getChildCount();
+                int selection = tree.getLeadSelectionRow();
+                fireTableRowsDeleted(start, start + length);
+                tree.setSelectionRow(selection);
+            }
+        });
+    }
+
+    @Override
+    public void fireTableRowsDeleted(final int firstRow, final int lastRow) {
+        super.fireTableRowsDeleted(firstRow, lastRow);
+    }
+
+    public int getColumnCount() {
+        return treeTableModel.getColumnCount();
+    }
+
+    public String getColumnName(final int column) {
+        return treeTableModel.getColumnName(column);
+    }
+
+    public Class<?> getColumnClass(final int column) {
+        return treeTableModel.getColumnClass(column);
+    }
+
+    public int getRowCount() {
+        return tree.getRowCount();
+    }
+
+    protected Object nodeForRow(final int row) {
+        TreePath treePath = tree.getPathForRow(row);
+        return treePath.getLastPathComponent();
+    }
+
+    public Object getValueAt(final int row, final int column) {
+        return treeTableModel.getValueAt(nodeForRow(row), column);
+    }
+
+    public boolean isCellEditable(final int row, final int column) {
+        return treeTableModel.isCellEditable(nodeForRow(row), column);
+    }
+
+    public void setValueAt(final Object value, final int row, final int column) {
+        treeTableModel.setValueAt(value, nodeForRow(row), column);
+    }
+}

core/src/main/java/com/github/weisj/darklaf/components/treetable/TreeTableSelectionModel.java

@@ -0,0 +1,30 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable;
+
+import javax.swing.*;
+import javax.swing.tree.TreeSelectionModel;
+
+public interface TreeTableSelectionModel extends TreeSelectionModel, ListSelectionModel {}

core/src/main/java/com/github/weisj/darklaf/components/treetable/TreeTableTree.java

@@ -0,0 +1,40 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable;
+
+import java.awt.*;
+
+import javax.swing.*;
+
+public class TreeTableTree extends JTree {
+
+    @Override
+    public void processEvent(final AWTEvent e) {
+        super.processEvent(e);
+    }
+
+    @Override
+    public void paint(final Graphics g) {}
+}

core/src/main/java/com/github/weisj/darklaf/components/treetable/model/AbstractTreeTableModel.java

@@ -0,0 +1,119 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable.model;
+
+import javax.swing.event.EventListenerList;
+import javax.swing.event.TreeModelEvent;
+import javax.swing.event.TreeModelListener;
+import javax.swing.tree.TreePath;
+
+public abstract class AbstractTreeTableModel implements TreeTableModel {
+    protected TreeTableNode root;
+    protected EventListenerList listenerList = new EventListenerList();
+
+    private static final int CHANGED = 0;
+    private static final int INSERTED = 1;
+    private static final int REMOVED = 2;
+    private static final int STRUCTURE_CHANGED = 3;
+
+    public AbstractTreeTableModel(final TreeTableNode root) {
+        this.root = root;
+    }
+
+    @Override
+    public TreeTableNode getRoot() {
+        return root;
+    }
+
+    @Override
+    public boolean isLeaf(final Object node) {
+        return getChildCount(node) == 0;
+    }
+
+    @Override
+    public void valueForPathChanged(final TreePath path, final Object newValue) {}
+
+    @Override
+    public int getIndexOfChild(final Object parent, final Object child) {
+        return 0;
+    }
+
+    @Override
+    public void addTreeModelListener(final TreeModelListener l) {
+        listenerList.add(TreeModelListener.class, l);
+    }
+
+    @Override
+    public void removeTreeModelListener(final TreeModelListener l) {
+        listenerList.remove(TreeModelListener.class, l);
+    }
+
+    private void fireTreeNode(final int changeType, final Object source, final Object[] path, final int[] childIndices,
+                              final Object[] children) {
+        Object[] listeners = listenerList.getListenerList();
+        TreeModelEvent e = new TreeModelEvent(source, path, childIndices, children);
+        for (int i = listeners.length - 2; i >= 0; i -= 2) {
+            if (listeners[i] == TreeModelListener.class) {
+                switch (changeType) {
+                    case CHANGED :
+                        ((TreeModelListener) listeners[i + 1]).treeNodesChanged(e);
+                        break;
+                    case INSERTED :
+                        ((TreeModelListener) listeners[i + 1]).treeNodesInserted(e);
+                        break;
+                    case REMOVED :
+                        ((TreeModelListener) listeners[i + 1]).treeNodesRemoved(e);
+                        break;
+                    case STRUCTURE_CHANGED :
+                        ((TreeModelListener) listeners[i + 1]).treeStructureChanged(e);
+                        break;
+                    default :
+                        break;
+                }
+
+            }
+        }
+    }
+
+    protected void fireTreeNodesChanged(final Object source, final Object[] path,
+                                        final int[] childIndices, final Object[] children) {
+        fireTreeNode(CHANGED, source, path, childIndices, children);
+    }
+
+    protected void fireTreeNodesInserted(final Object source, final Object[] path,
+                                         final int[] childIndices, final Object[] children) {
+        fireTreeNode(INSERTED, source, path, childIndices, children);
+    }
+
+    protected void fireTreeNodesRemoved(final Object source, final Object[] path,
+                                        final int[] childIndices, final Object[] children) {
+        fireTreeNode(REMOVED, source, path, childIndices, children);
+    }
+
+    protected void fireTreeStructureChanged(final Object source, final Object[] path,
+                                            final int[] childIndices, final Object[] children) {
+        fireTreeNode(STRUCTURE_CHANGED, source, path, childIndices, children);
+    }
+}

core/src/main/java/com/github/weisj/darklaf/components/treetable/model/DefaultTreeTableModel.java

@@ -0,0 +1,95 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable.model;
+
+import com.github.weisj.darklaf.util.DarkUIUtil;
+
+public class DefaultTreeTableModel extends AbstractTreeTableModel {
+
+    private final String[] headers;
+    private Class<?>[] columnClasses;
+
+    public DefaultTreeTableModel(final TreeTableNode root, final String[] headers) {
+        super(root);
+        this.headers = headers;
+    }
+
+    public void setColumnClasses(final Class<?>[] columnClasses) {
+        this.columnClasses = columnClasses;
+    }
+
+    @Override
+    public int getColumnCount() {
+        return headers.length;
+    }
+
+    @Override
+    public String getColumnName(final int column) {
+        return headers[column];
+    }
+
+    @Override
+    public Class<?> getColumnClass(final int column) {
+        if (column == 0) {
+            return TreeTableModel.class;
+        } else if (columnClasses != null && column < columnClasses.length) {
+            return columnClasses[column];
+        } else {
+            return Object.class;
+        }
+    }
+
+    @Override
+    public Object getValueAt(final Object node, final int column) {
+        TreeTableNode treeTableNode = DarkUIUtil.nullableCast(TreeTableNode.class, node);
+        if (treeTableNode == null) return null;
+        return treeTableNode.getValueAt(column);
+    }
+
+    @Override
+    public boolean isCellEditable(final Object node, final int column) {
+        return column != 0;
+    }
+
+    @Override
+    public void setValueAt(final Object aValue, final Object node, final int column) {
+        TreeTableNode treeTableNode = DarkUIUtil.nullableCast(TreeTableNode.class, node);
+        if (treeTableNode != null) {
+            treeTableNode.setValueAt(column, aValue);
+        }
+    }
+
+    @Override
+    public Object getChild(final Object parent, final int index) {
+        TreeTableNode treeTableNode = DarkUIUtil.nullableCast(TreeTableNode.class, parent);
+        return treeTableNode != null ? treeTableNode.getChildAt(index) : null;
+    }
+
+    @Override
+    public int getChildCount(final Object parent) {
+        TreeTableNode treeTableNode = DarkUIUtil.nullableCast(TreeTableNode.class, parent);
+        return treeTableNode != null ? treeTableNode.getChildCount() : 0;
+    }
+}

core/src/main/java/com/github/weisj/darklaf/components/treetable/model/DefaultTreeTableNode.java

@@ -0,0 +1,79 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable.model;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class DefaultTreeTableNode implements TreeTableNode {
+
+    private final List<TreeTableNode> children;
+    private final TreeTableNode parent;
+    private final List<Object> columns;
+
+    public DefaultTreeTableNode(final TreeTableNode parent,
+                                final Object[] columns) {
+        this(parent, Arrays.asList(columns));
+    }
+
+    public DefaultTreeTableNode(final TreeTableNode parent, final List<Object> columns) {
+        this.parent = parent;
+        this.columns = columns;
+        this.children = new ArrayList<>();
+    }
+
+    @Override
+    public List<TreeTableNode> getChildren() {
+        return children;
+    }
+
+    @Override
+    public TreeTableNode getParent() {
+        return parent;
+    }
+
+    @Override
+    public boolean getAllowsChildren() {
+        return true;
+    }
+
+    public void addChild(final TreeTableNode child) {
+        children.add(child);
+    }
+
+    public void removeChild(final TreeTableNode child) {
+        children.remove(child);
+    }
+
+    public String toString() {
+        return getTreeValue().toString();
+    }
+
+    @Override
+    public List<Object> getColumns() {
+        return columns;
+    }
+}

core/src/main/java/com/github/weisj/darklaf/components/treetable/model/DefaultTreeTableSelectionModel.java

@@ -0,0 +1,99 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable.model;
+
+import javax.swing.*;
+import javax.swing.tree.DefaultTreeSelectionModel;
+import javax.swing.tree.TreePath;
+
+public class DefaultTreeTableSelectionModel extends DefaultTreeSelectionModel
+                                            implements DelegatingListSelectionModel {
+
+    private final JTree tree;
+    private final ListSelectionModel bridgeModel;
+
+    public DefaultTreeTableSelectionModel(final JTree tree) {
+        this.tree = tree;
+        bridgeModel = new TreeTableListSelectionModel();
+    }
+
+    @Override
+    public ListSelectionModel getListDelegate() {
+        return bridgeModel;
+    }
+
+    protected class TreeTableListSelectionModel implements DelegatingListSelectionModel {
+
+        @Override
+        public ListSelectionModel getListDelegate() {
+            return listSelectionModel;
+        }
+
+        @Override
+        public void setSelectionInterval(final int index0, final int index1) {
+            setSelectionPaths(getTreePaths(index0, index1));
+        }
+
+        @Override
+        public void addSelectionInterval(final int index0, final int index1) {
+            addSelectionPaths(getTreePaths(index0, index1));
+        }
+
+        protected TreePath[] getTreePaths(final int index0, final int index1) {
+            int start = Math.min(index0, index1);
+            int end = Math.max(index0, index1);
+            TreePath[] paths = new TreePath[end - start + 1];
+            for (int i = start; i <= end; i++) {
+                paths[i - start] = tree.getPathForRow(i);
+            }
+            return paths;
+        }
+
+        @Override
+        public void removeSelectionInterval(final int index0, final int index1) {
+            removeSelectionPaths(getTreePaths(index0, index1));
+        }
+
+        @Override
+        public void setLeadSelectionIndex(final int index) {
+            tree.setLeadSelectionPath(tree.getPathForRow(index));
+        }
+
+        @Override
+        public int getLeadSelectionIndex() {
+            return getLeadSelectionRow();
+        }
+
+        @Override
+        public void setAnchorSelectionIndex(final int index) {
+            tree.setAnchorSelectionPath(tree.getPathForRow(index));
+        }
+
+        @Override
+        public int getAnchorSelectionIndex() {
+            return tree.getRowForPath(tree.getAnchorSelectionPath());
+        }
+    }
+}

core/src/main/java/com/github/weisj/darklaf/components/treetable/model/DelegatingListSelectionModel.java

@@ -0,0 +1,166 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable.model;
+
+import javax.swing.*;
+import javax.swing.event.ListSelectionListener;
+
+public interface DelegatingListSelectionModel extends ListSelectionModel {
+    ListSelectionModel getListDelegate();
+
+    @Override
+    default void setSelectionInterval(final int index0, final int index1) {
+        getListDelegate().setSelectionInterval(index0, index1);
+    }
+
+    @Override
+    default void addSelectionInterval(final int index0, final int index1) {
+        getListDelegate().addSelectionInterval(index0, index1);
+
+    }
+
+    @Override
+    default void removeSelectionInterval(final int index0, final int index1) {
+        getListDelegate().removeSelectionInterval(index0, index1);
+    }
+
+    @Override
+    default int getMinSelectionIndex() {
+        return getListDelegate().getMinSelectionIndex();
+    }
+
+    @Override
+    default int getMaxSelectionIndex() {
+        return getListDelegate().getMaxSelectionIndex();
+    }
+
+    @Override
+    default boolean isSelectedIndex(final int index) {
+        return getListDelegate().isSelectedIndex(index);
+    }
+
+    @Override
+    default int getAnchorSelectionIndex() {
+        return getListDelegate().getAnchorSelectionIndex();
+    }
+
+    @Override
+    default void setAnchorSelectionIndex(final int index) {
+        getListDelegate().setAnchorSelectionIndex(index);
+    }
+
+    @Override
+    default int getLeadSelectionIndex() {
+        return getListDelegate().getLeadSelectionIndex();
+    }
+
+    @Override
+    default void setLeadSelectionIndex(final int index) {
+        getListDelegate().setLeadSelectionIndex(index);
+    }
+
+    @Override
+    default void clearSelection() {
+        getListDelegate().clearSelection();
+    }
+
+    @Override
+    default boolean isSelectionEmpty() {
+        return getListDelegate().isSelectionEmpty();
+    }
+
+    @Override
+    default void insertIndexInterval(final int index, final int length, final boolean before) {
+        getListDelegate().insertIndexInterval(index, length, before);
+    }
+
+    @Override
+    default void removeIndexInterval(final int index0, final int index1) {
+        getListDelegate().removeIndexInterval(index0, index1);
+    }
+
+    @Override
+    default void setValueIsAdjusting(final boolean valueIsAdjusting) {
+        getListDelegate().setValueIsAdjusting(valueIsAdjusting);
+    }
+
+    @Override
+    default boolean getValueIsAdjusting() {
+        return getListDelegate().getValueIsAdjusting();
+    }
+
+    @Override
+    default void setSelectionMode(final int selectionMode) {
+        getListDelegate().setSelectionMode(selectionMode);
+    }
+
+    @Override
+    default int getSelectionMode() {
+        return getListDelegate().getSelectionMode();
+    }
+
+    @Override
+    default void addListSelectionListener(final ListSelectionListener x) {
+        getListDelegate().addListSelectionListener(x);
+    }
+
+    @Override
+    default void removeListSelectionListener(final ListSelectionListener x) {
+        getListDelegate().removeListSelectionListener(x);
+    }
+
+    default int[] getSelectedIndices() {
+        int iMin = getMinSelectionIndex();
+        int iMax = getMaxSelectionIndex();
+
+        if ((iMin < 0) || (iMax < 0)) {
+            return new int[0];
+        }
+
+        int[] rvTmp = new int[1 + (iMax - iMin)];
+        int n = 0;
+        for (int i = iMin; i <= iMax; i++) {
+            if (isSelectedIndex(i)) {
+                rvTmp[n++] = i;
+            }
+        }
+        int[] rv = new int[n];
+        System.arraycopy(rvTmp, 0, rv, 0, n);
+        return rv;
+    }
+
+    default int getSelectedItemsCount() {
+        int iMin = getMinSelectionIndex();
+        int iMax = getMaxSelectionIndex();
+        int count = 0;
+
+        for (int i = iMin; i <= iMax; i++) {
+            if (isSelectedIndex(i)) {
+                count++;
+            }
+        }
+        return count;
+    }
+}

core/src/main/java/com/github/weisj/darklaf/components/treetable/model/TreeTableModel.java

@@ -0,0 +1,80 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable.model;
+
+import javax.swing.tree.TreeModel;
+
+public interface TreeTableModel extends TreeModel {
+
+    /**
+     * Returns the number of available columns.
+     *
+     * @return Number of Columns
+     */
+    int getColumnCount();
+
+    /**
+     * Returns the column name.
+     *
+     * @param  column Column number
+     * @return        Column name
+     */
+    String getColumnName(int column);
+
+    /**
+     * Returns the type (class) of a column.
+     *
+     * @param  column Column number
+     * @return        Class
+     */
+    Class<?> getColumnClass(int column);
+
+    /**
+     * Returns the value of a node in a column.
+     *
+     * @param  node   Node
+     * @param  column Column number
+     * @return        Value of the node in the column
+     */
+    Object getValueAt(Object node, int column);
+
+    /**
+     * Check if a cell of a node in one column is editable.
+     *
+     * @param  node   Node
+     * @param  column Column number
+     * @return        true/false
+     */
+    boolean isCellEditable(Object node, int column);
+
+    /**
+     * Sets a value for a node in one column.
+     *
+     * @param aValue New value
+     * @param node   Node
+     * @param column Column number
+     */
+    void setValueAt(Object aValue, Object node, int column);
+}

core/src/main/java/com/github/weisj/darklaf/components/treetable/model/TreeTableNode.java

@@ -0,0 +1,88 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package com.github.weisj.darklaf.components.treetable.model;
+
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.List;
+
+import javax.swing.tree.TreeNode;
+
+public interface TreeTableNode extends TreeNode {
+
+    List<TreeTableNode> getChildren();
+
+    @Override
+    default Enumeration<? extends TreeTableNode> children() {
+        return Collections.enumeration(getChildren());
+    }
+
+    @Override
+    TreeTableNode getParent();
+
+    @Override
+    default int getIndex(final TreeNode node) {
+        if (!(node instanceof TreeTableNode)) return -1;
+        return getIndex((TreeTableNode) node);
+    }
+
+    default int getIndex(final TreeTableNode node) {
+        return getChildren().indexOf(node);
+    }
+
+    @Override
+    default int getChildCount() {
+        return getChildren().size();
+    }
+
+    @Override
+    default TreeTableNode getChildAt(final int index) {
+        if (index < 0 || index >= getChildCount()) return null;
+        return getChildren().get(index);
+    }
+
+    @Override
+    default boolean isLeaf() {
+        return getChildCount() == 0;
+    }
+
+    List<Object> getColumns();
+
+    default Object getValueAt(final int column) {
+        return getColumns().get(column);
+    }
+
+    default Object getTreeValue() {
+        return getColumns().get(0);
+    }
+
+    default int getColumnCount() {
+        return getColumns().size();
+    }
+
+    default void setValueAt(final int column, final Object aValue) {
+        getColumns().set(column, aValue);
+    }
+}

core/src/main/java/com/github/weisj/darklaf/ui/table/renderer/DarkTableCellRendererDelegate.java

@@ -27,6 +27,7 @@ package com.github.weisj.darklaf.ui.table.renderer;
 import java.awt.*;
 
 import javax.swing.*;
+import javax.swing.border.Border;
 import javax.swing.table.JTableHeader;
 import javax.swing.table.TableCellRenderer;
 import javax.swing.table.TableColumn;
@@ -64,7 +65,7 @@ public class DarkTableCellRendererDelegate extends TableCellRendererDelegate imp
         boolean paintSelected = isSelected && !isLeadSelectionCell && !table.isEditing();
 
         if (component instanceof JComponent) {
-            setupBorderStyle(table, row, column, (JComponent) component, isRowFocus);
+            setupBorderStyle(table, row, column, (JComponent) component, isLeadSelectionCell, isRowFocus);
         }
         CellUtil.setupTableForeground(component, table, paintSelected);
         CellUtil.setupTableBackground(component, table, paintSelected, row);
@@ -72,26 +73,32 @@ public class DarkTableCellRendererDelegate extends TableCellRendererDelegate imp
     }
 
     public void setupBorderStyle(final JTable table, final int row, final int column,
-                                 final JComponent component, final boolean isRowFocus) {
-        if (isRowFocus
+                                 final JComponent component, final boolean isLeadSelectionCell,
+                                 final boolean isRowFocus) {
+        Border focusBorder = UIManager.getBorder("Table.focusSelectedCellHighlightBorder");
+        if (isLeadSelectionCell
             && table.getSelectionModel().getLeadSelectionIndex() == row
             && DarkUIUtil.hasFocus(table)
             && !table.isEditing()) {
-            LookAndFeel.installBorder(component, "Table.focusSelectedCellHighlightBorder");
-            component.putClientProperty(KEY_FULL_ROW_FOCUS_BORDER, true);
-            JTableHeader header = table.getTableHeader();
-            TableColumn draggedColumn = (header == null) ? null : header.getDraggedColumn();
-            boolean forceLeft = false;
-            boolean forceRight = false;
-            if (draggedColumn != null) {
-                int index = DarkTableUI.viewIndexForColumn(draggedColumn, table);
-                forceLeft = column == index + 1 || column == index;
-                forceRight = column == index - 1 || column == index;
+            PropertyUtil.installBorder(component, focusBorder);
+            if (isRowFocus) {
+                component.putClientProperty(KEY_FULL_ROW_FOCUS_BORDER, true);
+                JTableHeader header = table.getTableHeader();
+                TableColumn draggedColumn = (header == null) ? null : header.getDraggedColumn();
+                boolean forceLeft = false;
+                boolean forceRight = false;
+                if (draggedColumn != null) {
+                    int index = DarkTableUI.viewIndexForColumn(draggedColumn, table);
+                    forceLeft = column == index + 1 || column == index;
+                    forceRight = column == index - 1 || column == index;
+                }
+                component.putClientProperty(KEY_FORCE_RIGHT_BORDER, forceRight);
+                component.putClientProperty(KEY_FORCE_LEFT_BORDER, forceLeft);
+            } else {
+                component.putClientProperty(KEY_FULL_ROW_FOCUS_BORDER, false);
             }
-            component.putClientProperty(KEY_FORCE_RIGHT_BORDER, forceRight);
-            component.putClientProperty(KEY_FORCE_LEFT_BORDER, forceLeft);
-        } else {
-            component.putClientProperty(KEY_FULL_ROW_FOCUS_BORDER, false);
+        } else if (component.getBorder() == focusBorder) {
+            component.setBorder(null);
         }
     }
 

core/src/main/java/com/github/weisj/darklaf/ui/tree/DarkTreeUI.java

@@ -34,7 +34,10 @@ import javax.swing.*;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.UIResource;
 import javax.swing.plaf.basic.BasicTreeUI;
-import javax.swing.tree.*;
+import javax.swing.tree.DefaultTreeCellRenderer;
+import javax.swing.tree.TreeCellEditor;
+import javax.swing.tree.TreeCellRenderer;
+import javax.swing.tree.TreePath;
 
 import com.github.weisj.darklaf.graphics.PaintUtil;
 import com.github.weisj.darklaf.ui.cell.CellConstants;
@@ -62,6 +65,9 @@ public class DarkTreeUI extends BasicTreeUI implements PropertyChangeListener, C
     public static final String STYLE_NONE = "none";
     public static final String KEY_IS_TREE_EDITOR = "JComponent.isTreeEditor";
     public static final String KEY_IS_TREE_RENDERER = "JComponent.isTreeRenderer";
+    public static final String KEY_IS_TABLE_TREE = "JComponent.isTableTree";
+
+    protected static final Rectangle boundsBuffer = new Rectangle();
 
     protected MouseListener selectionListener;
     protected Color lineColor;
@@ -168,34 +174,33 @@ public class DarkTreeUI extends BasicTreeUI implements PropertyChangeListener, C
 
         tree.putClientProperty(KEY_MAC_ACTIONS_INSTALLED, Boolean.TRUE);
 
-        final InputMap inputMap = tree.getInputMap(JComponent.WHEN_FOCUSED);
-        inputMap.put(KeyStroke.getKeyStroke("pressed LEFT"), "collapse_or_move_up");
-        inputMap.put(KeyStroke.getKeyStroke("pressed RIGHT"), "expand_or_move_down");
-        inputMap.put(KeyStroke.getKeyStroke("pressed DOWN"), "move_down");
-        inputMap.put(KeyStroke.getKeyStroke("pressed UP"), "move_up");
-        inputMap.put(KeyStroke.getKeyStroke("pressed ENTER"), "toggle_edit");
+        installInputMap(tree.getInputMap(JComponent.WHEN_FOCUSED));
 
         final ActionMap actionMap = tree.getActionMap();
 
-        final Action expandAction = actionMap.get("expand");
-        if (expandAction != null) {
-            actionMap.put("expand_or_move_down", new TreeUIAction() {
-                @Override
-                public void actionPerformed(final ActionEvent e) {
-                    JTree tree = getTree(e);
-                    if (tree == null) return;
-                    int selectionRow = tree.getLeadSelectionRow();
-                    if (selectionRow == -1) return;
-
-                    if (isLeaf(selectionRow) || tree.isExpanded(selectionRow)) {
+        actionMap.put("expand_or_move_down", new TreeUIAction() {
+            @Override
+            public void actionPerformed(final ActionEvent e) {
+                JTree tree = getTree(e);
+                if (tree == null) return;
+                int selectionRow = tree.getLeadSelectionRow();
+                if (selectionRow == -1) return;
+
+                if (isLeaf(selectionRow) || tree.isExpanded(selectionRow)) {
+                    if (!PropertyUtil.getBooleanProperty(tree, KEY_IS_TABLE_TREE)) {
                         moveTo(tree, selectionRow + 1);
-                    } else {
-                        expandAction.actionPerformed(e);
                     }
-                    tree.repaint();
+                } else {
+                    tree.expandRow(selectionRow);
                 }
-            });
-        }
+                tree.repaint();
+            }
+
+            @Override
+            public boolean accept(final Object sender) {
+                return acceptExpandCollapseAction(sender, false);
+            }
+        });
 
         actionMap.put("collapse_or_move_up", new TreeUIAction() {
             @Override
@@ -206,12 +211,19 @@ public class DarkTreeUI extends BasicTreeUI implements PropertyChangeListener, C
                 if (selectionRow == -1) return;
 
                 if (isLeaf(selectionRow) || tree.isCollapsed(selectionRow)) {
-                    moveTo(tree, selectionRow - 1);
+                    if (!PropertyUtil.getBooleanProperty(tree, KEY_IS_TABLE_TREE)) {
+                        moveTo(tree, selectionRow - 1);
+                    }
                 } else {
                     tree.collapseRow(selectionRow);
                 }
                 tree.repaint();
             }
+
+            @Override
+            public boolean accept(final Object sender) {
+                return acceptExpandCollapseAction(sender, true);
+            }
         });
 
         actionMap.put("move_down", new TreeUIAction() {
@@ -236,6 +248,28 @@ public class DarkTreeUI extends BasicTreeUI implements PropertyChangeListener, C
         });
     }
 
+    protected boolean acceptExpandCollapseAction(final Object sender, final boolean collapsed) {
+        JTree tree = DarkUIUtil.nullableCast(JTree.class, sender);
+        if (tree == null) return false;
+        int selectionRow = tree.getLeadSelectionRow();
+        if (selectionRow == -1) return false;
+        final boolean collapsedOrExpanded = collapsed
+                ? tree.isCollapsed(selectionRow)
+                : tree.isExpanded(selectionRow);
+        if (isLeaf(selectionRow) || collapsedOrExpanded) {
+            return !PropertyUtil.getBooleanProperty(tree, KEY_IS_TABLE_TREE);
+        }
+        return true;
+    }
+
+    protected void installInputMap(final InputMap inputMap) {
+        inputMap.put(KeyStroke.getKeyStroke("pressed LEFT"), "collapse_or_move_up");
+        inputMap.put(KeyStroke.getKeyStroke("pressed RIGHT"), "expand_or_move_down");
+        inputMap.put(KeyStroke.getKeyStroke("pressed DOWN"), "move_down");
+        inputMap.put(KeyStroke.getKeyStroke("pressed UP"), "move_up");
+        inputMap.put(KeyStroke.getKeyStroke("pressed ENTER"), "toggle_edit");
+    }
+
     protected JTree getTree(final ActionEvent e) {
         return DarkUIUtil.nullableCast(JTree.class, e.getSource());
     }
@@ -268,29 +302,6 @@ public class DarkTreeUI extends BasicTreeUI implements PropertyChangeListener, C
         tree.scrollRectToVisible(bounds);
     }
 
-    protected void collapse(final JTree tree) {
-        int selectionRow = tree.getLeadSelectionRow();
-        if (selectionRow == -1) return;
-
-        TreePath selectionPath = tree.getPathForRow(selectionRow);
-        if (selectionPath == null) return;
-
-        if (tree.getModel().isLeaf(selectionPath.getLastPathComponent())
-            || tree.isCollapsed(selectionRow)) {
-            final TreePath parentPath = tree.getPathForRow(selectionRow).getParentPath();
-            if (parentPath != null) {
-                if (parentPath.getParentPath() != null || tree.isRootVisible()) {
-                    final int parentRow = tree.getRowForPath(parentPath);
-                    scrollRowToVisible(tree, parentRow);
-                    tree.setSelectionRow(parentRow);
-                }
-            }
-        } else {
-            tree.collapseRow(selectionRow);
-        }
-        tree.repaint();
-    }
-
     protected void toggleEdit(final JTree tree) {
         if (tree == null) return;
         if (tree.isEditing()) {
@@ -394,97 +405,14 @@ public class DarkTreeUI extends BasicTreeUI implements PropertyChangeListener, C
         Insets insets = tree.getInsets();
         TreePath initialPath = getClosestPathForLocation(tree, 0, paintBounds.y);
         Enumeration<?> paintingEnumerator = treeState.getVisiblePathsFrom(initialPath);
-        int row = treeState.getRowForPath(initialPath);
-        int endY = paintBounds.y + paintBounds.height;
-
-        drawingCache.clear();
 
         if (initialPath != null && paintingEnumerator != null) {
-            TreePath parentPath = initialPath;
-
-            // Draw the lines, knobs, and rows
+            int row = treeState.getRowForPath(initialPath);
 
             boolean done = false;
-            // Information for the node being rendered.
-            boolean isExpanded;
-            boolean hasBeenExpanded;
-            boolean isLeaf;
-            Rectangle boundsBuffer = new Rectangle();
-            Rectangle bounds;
-            TreePath path;
-            boolean rootVisible = isRootVisible();
-
-            final int containerWidth = tree.getParent() instanceof JViewport
-                    ? tree.getParent().getWidth()
-                    : tree.getWidth();
-            final int xOffset = tree.getParent() instanceof JViewport
-                    ? ((JViewport) tree.getParent()).getViewPosition().x
-                    : 0;
-
-            // Paint row backgrounds
-            Enumeration<?> backgroundEnumerator = treeState.getVisiblePathsFrom(initialPath);
-            while (backgroundEnumerator != null && backgroundEnumerator.hasMoreElements()) {
-                path = (TreePath) backgroundEnumerator.nextElement();
-                if (path != null) {
-                    bounds = getPathBounds(path, insets, boundsBuffer);
-                    if (bounds == null) return;
-                    bounds.x = xOffset;
-                    bounds.width = containerWidth;
-                    if (paintBounds.intersects(bounds)) {
-                        paintRowBackground(g, paintBounds, bounds, path, tree.getRowForPath(path));
-                    }
-                }
-            }
-
-            // Find each parent and have them draw a line to their last child
-            while (parentPath != null) {
-                paintVerticalPartOfLeg(g, paintBounds, insets, parentPath);
-                drawingCache.put(parentPath, Boolean.TRUE);
-                parentPath = parentPath.getParentPath();
-            }
-
             while (!done && paintingEnumerator.hasMoreElements()) {
-                path = (TreePath) paintingEnumerator.nextElement();
-                if (path != null) {
-                    isLeaf = treeModel.isLeaf(path.getLastPathComponent());
-                    if (isLeaf) {
-                        isExpanded = hasBeenExpanded = false;
-                    } else {
-                        isExpanded = treeState.getExpandedState(path);
-                        hasBeenExpanded = tree.hasBeenExpanded(path);
-                    }
-                    bounds = getPathBounds(path, insets, boundsBuffer);
-                    if (bounds == null)
-                    // This will only happen if the model changes out
-                    // from under us (usually in another thread).
-                    // Swing isn't multithreaded, but I'll put this
-                    // check in anyway.
-                    {
-                        return;
-                    }
-
-                    // See if the vertical line to the parent has been drawn.
-                    parentPath = path.getParentPath();
-                    if (parentPath != null) {
-                        if (drawingCache.get(parentPath) == null) {
-                            paintVerticalPartOfLeg(g, paintBounds, insets, parentPath);
-                            drawingCache.put(parentPath, Boolean.TRUE);
-                        }
-                        paintHorizontalPartOfLeg(g, paintBounds, insets, bounds, path, row, isExpanded,
-                                                 hasBeenExpanded, isLeaf);
-                    } else if (rootVisible && row == 0) {
-                        paintHorizontalPartOfLeg(g, paintBounds, insets, bounds, path, row, isExpanded,
-                                                 hasBeenExpanded, isLeaf);
-                    }
-                    if (shouldPaintExpandControl(path, row, isExpanded, hasBeenExpanded, isLeaf)) {
-                        paintExpandControl(g, paintBounds, insets, bounds, path, row, isExpanded,
-                                           hasBeenExpanded, isLeaf);
-                    }
-                    paintRow(g, paintBounds, insets, bounds, path, row, isExpanded, hasBeenExpanded, isLeaf);
-                    if ((bounds.y + bounds.height) >= endY) {
-                        done = true;
-                    }
-                } else {
+                TreePath path = (TreePath) paintingEnumerator.nextElement();
+                if (!paintSingleRow(g, paintBounds, insets, path, row)) {
                     done = true;
                 }
                 row++;
@@ -493,34 +421,54 @@ public class DarkTreeUI extends BasicTreeUI implements PropertyChangeListener, C
         paintDropLine(g);
         // Empty out the renderer pane, allowing renderers to be gc'ed.
         rendererPane.removeAll();
-        drawingCache.clear();
     }
 
-    @Override
-    public TreeCellRenderer getCellRenderer() {
-        return super.getCellRenderer();
+    public void paintRow(final Graphics g, final int row) {
+        TreePath path = getPathForRow(tree, row);
+        Rectangle paintBounds = g.getClipBounds();
+        Insets insets = tree.getInsets();
+        Rectangle rowBounds = getPathBounds(path, insets, boundsBuffer);
+        g.translate(0, -rowBounds.y);
+        paintBounds.y += rowBounds.y;
+        paintSingleRow(g, paintBounds, insets, path, row);
+        rendererPane.removeAll();
+        g.translate(0, rowBounds.y);
     }
 
-    public Component getEditingComponent() {
-        return editingComponent;
-    }
+    protected boolean paintSingleRow(final Graphics g, final Rectangle paintBounds, final Insets insets,
+                                     final TreePath path, final int row) {
+        if (path == null) return false;
+        final int xOffset = tree.getParent() instanceof JViewport
+                ? ((JViewport) tree.getParent()).getViewPosition().x
+                : 0;
+        final int containerWidth = tree.getParent() instanceof JViewport
+                ? tree.getParent().getWidth()
+                : tree.getWidth();
+        final Rectangle cellBounds = getPathBounds(path, insets, boundsBuffer);
+        if (cellBounds == null) return false;
+        final int boundsX = cellBounds.x;
+        final int boundsWidth = cellBounds.width;
 
-    public int getEditingRow() {
-        return editingRow;
-    }
+        cellBounds.x = xOffset;
+        cellBounds.width = containerWidth;
+        paintRowBackground(g, paintBounds, cellBounds, path, row);
+        cellBounds.x = boundsX;
+        cellBounds.width = boundsWidth;
 
-    protected Rectangle getPathBounds(final TreePath path, final Insets insets, Rectangle bounds) {
-        bounds = treeState.getBounds(path, bounds);
-        if (bounds != null) {
-            if (tree.getComponentOrientation().isLeftToRight()) {
-                bounds.x += insets.left;
-            } else {
-                bounds.x = tree.getWidth() - (bounds.x + bounds.width) -
-                           insets.right;
-            }
-            bounds.y += insets.top;
+        if (path.getParentPath() != null) {
+            paintVerticalLegs(g, paintBounds, cellBounds, insets, path);
         }
-        return bounds;
+
+        boolean isLeaf = treeModel.isLeaf(path.getLastPathComponent());
+        boolean isExpanded = !isLeaf && treeState.getExpandedState(path);
+        boolean hasBeenExpanded = !isLeaf && tree.hasBeenExpanded(path);
+
+        if (shouldPaintExpandControl(path, row, isExpanded, hasBeenExpanded, isLeaf)) {
+            paintExpandControl(g, paintBounds, insets, cellBounds, path, row, isExpanded,
+                               hasBeenExpanded, isLeaf);
+        }
+        paintRow(g, paintBounds, insets, cellBounds, path, row, isExpanded, hasBeenExpanded, isLeaf);
+        return (cellBounds.y + cellBounds.height) < paintBounds.y + paintBounds.height;
     }
 
     protected void paintRowBackground(final Graphics g, final Rectangle clipBounds,
@@ -541,12 +489,76 @@ public class DarkTreeUI extends BasicTreeUI implements PropertyChangeListener, C
         }
     }
 
+    /*
+     * Paint all vertical legs for the whole tree in this row.
+     */
+    protected void paintVerticalLegs(final Graphics g, final Rectangle clipBounds,
+                                     final Rectangle rowBounds,
+                                     final Insets insets, final TreePath path) {
+        if (!shouldPaintLines()) return;
+        int depth = path.getPathCount() - 1;
+        if (depth == 0 && (!isRootVisible() || !getShowsRootHandles())) {
+            // Parent is the root, which isn't visible.
+            return;
+        }
+        int clipLeft = clipBounds.x;
+        int clipRight = clipBounds.x + (clipBounds.width - 1);
+
+        TreePath parentPath = path;
+        for (int currentDepth = depth - 1; currentDepth >= 0; currentDepth--) {
+            if (currentDepth == 0 && !isRootVisible()) continue;
+
+            int lineX = getRowX(-1, currentDepth);
+            if (tree.getComponentOrientation().isLeftToRight()) {
+                lineX = lineX - getRightChildIndent() + insets.left;
+            } else {
+                lineX = tree.getWidth() - lineX - insets.right + getRightChildIndent() - 1;
+            }
+
+            if (lineX > clipRight || lineX < clipLeft) continue;
+
+            parentPath = parentPath.getParentPath();
+            g.setColor(getLineColor(parentPath));
+            paintVerticalLine(g, tree, lineX, rowBounds.y, rowBounds.y + rowBounds.height);
+        }
+    }
+
+    @Override
+    public TreeCellRenderer getCellRenderer() {
+        return super.getCellRenderer();
+    }
+
+    public Component getEditingComponent() {
+        return editingComponent;
+    }
+
+    public int getEditingRow() {
+        return editingRow;
+    }
+
+    protected Rectangle getPathBounds(final TreePath path, final Insets insets, Rectangle bounds) {
+        bounds = treeState.getBounds(path, bounds);
+        if (bounds != null) {
+            if (tree.getComponentOrientation().isLeftToRight()) {
+                bounds.x += insets.left;
+            } else {
+                bounds.x = tree.getWidth() - (bounds.x + bounds.width) - insets.right;
+            }
+            bounds.y += insets.top;
+        }
+        return bounds;
+    }
+
     @Override
     public void update(final Graphics g, final JComponent c) {
         if (popupListener != null) popupListener.repaint();
         super.update(g, c);
     }
 
+    public CellHintPopupListener<JTree, ?> getPopupListener() {
+        return popupListener;
+    }
+
     @Override
     protected void updateRenderer() {
         super.updateRenderer();
@@ -628,89 +640,14 @@ public class DarkTreeUI extends BasicTreeUI implements PropertyChangeListener, C
 
     @Override
     protected void paintVerticalPartOfLeg(final Graphics g, final Rectangle clipBounds,
-                                          final Insets insets, final TreePath path) {
-        if (!shouldPaintLines()) return;
-        int depth = path.getPathCount() - 1;
-        if (depth == 0 && !getShowsRootHandles() && !isRootVisible()) {
-            return;
-        }
-        if (treeModel.isLeaf(path.getLastPathComponent()) || !tree.isExpanded(path)) return;
-
-        int clipLeft = clipBounds.x;
-        int clipRight = clipBounds.x + (clipBounds.width - 1);
-        int clipTop = clipBounds.y;
-        int clipBottom = clipBounds.y + tree.getHeight();
-
-        Rectangle parentBounds = getPathBounds(tree, path);
-
-        int top;
-        int bottom;
-        int lineX = getRowX(-1, depth);
-
-        if (tree.getComponentOrientation().isLeftToRight()) {
-            lineX = lineX - getRightChildIndent() + insets.left;
-        } else {
-            lineX = tree.getWidth() - lineX - insets.right + getRightChildIndent() - 1;
-        }
-
-        if (lineX > clipRight || lineX < clipLeft) return;
-
-        if (parentBounds == null) {
-            top = Math.max(insets.top + getVerticalLegBuffer(), clipTop);
-        } else {
-            top = Math.max(parentBounds.y + parentBounds.height + getVerticalLegBuffer(), clipTop);
-        }
-
-        if (depth == 0 && !isRootVisible()) {
-            TreeModel model = getModel();
-
-            if (model != null) {
-                Object root = model.getRoot();
-
-                if (model.getChildCount(root) > 0) {
-                    parentBounds = getPathBounds(tree, path.pathByAddingChild(model.getChild(root, 0)));
-                    if (parentBounds != null) {
-                        top = Math.max(insets.top + getVerticalLegBuffer(), parentBounds.y + parentBounds.height / 2);
-                    }
-                }
-            }
-        }
-
-        int childCount = treeModel.getChildCount(path.getLastPathComponent());
-        g.setColor(getLineColor(path));
-        for (int i = 0; i < childCount - 1; i++) {
-            TreePath childPath = path.pathByAddingChild(treeModel.getChild(path.getLastPathComponent(), i));
-            Rectangle childBounds = getPathBounds(tree, childPath);
-            if (childBounds != null) {
-                bottom = Math.min(childBounds.y + childBounds.height, clipBottom);
-                paintVerticalLine(g, tree, lineX, top, bottom);
-                top = bottom;
-                if (clipBottom < top) return;
-            }
-        }
-
-        // Descend to deepest last child.
-        TreePath lastChildPath = path.pathByAddingChild(treeModel.getChild(path.getLastPathComponent(),
-                                                                           childCount - 1));
-        while (tree.isExpanded(lastChildPath)) {
-            int count = treeModel.getChildCount(lastChildPath.getLastPathComponent());
-            if (count == 0) break;
-            lastChildPath = lastChildPath.pathByAddingChild(treeModel.getChild(lastChildPath.getLastPathComponent(),
-                                                                               count - 1));
-        }
-        Rectangle childBounds = getPathBounds(tree, lastChildPath);
-        if (childBounds != null) {
-            bottom = Math.min(childBounds.y + childBounds.height, clipBottom);
-            paintVerticalLine(g, tree, lineX, top, bottom);
-        }
-    }
+                                          final Insets insets, final TreePath path) {}
 
     @Override
     protected void paintExpandControl(final Graphics g, final Rectangle clipBounds, final Insets insets,
                                       final Rectangle bounds, final TreePath path, final int row,
                                       final boolean isExpanded, final boolean hasBeenExpanded, final boolean isLeaf) {
         if (!isLeaf(row)) {
-            boolean isPathSelected = tree.getSelectionModel().isPathSelected(path);
+            boolean isPathSelected = tree.isPathSelected(path);
             setExpandedIcon(getExpandedIcon(isPathSelected, tree.hasFocus() || tree.isEditing()));
             setCollapsedIcon(getCollapsedIcon(isPathSelected, tree.hasFocus() || tree.isEditing()));
         }

core/src/test/java/ui/tree/TreeDemo.java

@@ -54,12 +54,23 @@ public class TreeDemo implements ComponentDemo {
         DefaultMutableTreeNode child1 = new SelectableTreeNode("Leaf B (boolean)", true);
         DefaultMutableTreeNode parent2 = new DefaultMutableTreeNode("Node B");
         DefaultMutableTreeNode child2 = new DefaultMutableTreeNode("Leaf that is unnecessary verbose and ridiculously long C");
+        DefaultMutableTreeNode parent3 = new DefaultMutableTreeNode("Nested");
+
+        DefaultMutableTreeNode current = parent3;
+        for (int i = 0; i < 10; i++) {
+            DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("Nested1 " + i);
+            DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("Nested2 " + i);
+            current.add(node1);
+            current.add(node2);
+            current = node1;
+        }
 
         parent1.add(child);
         parent1.add(child1);
         parent2.add(child2);
         root.add(parent1);
         root.add(parent2);
+        root.add(parent3);
 
         for (int i = 0; i < 100; i++) {
             root.add(new DefaultMutableTreeNode("Leaf " + i));
@@ -103,6 +114,12 @@ public class TreeDemo implements ComponentDemo {
                         : ComponentOrientation.RIGHT_TO_LEFT));
             }
         });
+        controlPanel.add(new JCheckBox("show root") {
+            {
+                setSelected(tree.isRootVisible());
+                addActionListener(e -> tree.setRootVisible(isSelected()));
+            }
+        });
         controlPanel.add(new JCheckBox("show root handles") {
             {
                 setSelected(tree.getShowsRootHandles());

core/src/test/java/ui/treetable/TreeTableDemo.java

@@ -0,0 +1,96 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package ui.treetable;
+
+import java.awt.*;
+import java.util.Date;
+import java.util.Random;
+
+import javax.swing.*;
+
+import com.github.weisj.darklaf.components.treetable.JTreeTable;
+import com.github.weisj.darklaf.components.treetable.model.*;
+
+import ui.ComponentDemo;
+import ui.DemoPanel;
+
+public class TreeTableDemo implements ComponentDemo {
+
+    public static void main(final String[] args) {
+        ComponentDemo.showDemo(new TreeTableDemo());
+    }
+
+    @Override
+    public JComponent createComponent() {
+        AbstractTreeTableModel treeTableModel = new DemoModel(createDataStructure());
+        JTreeTable treeTable = new JTreeTable(treeTableModel);
+        return new DemoPanel(new JScrollPane(treeTable), new BorderLayout(), 0);
+    }
+
+    private DemoNode createDataStructure() {
+        Random r = new Random();
+        DemoNode root = new DemoNode(null, "R1", "R1", new Date(r.nextLong()), 10);
+        for (int i = 0; i < 16; i++) {
+            DefaultTreeTableNode node = new DemoNode(root, "N" + i, "C1", new Date(r.nextLong()), 10);
+            if (i % 2 == 0) {
+                node.addChild(new DemoNode(node, "N12N12N12", "C12", new Date(r.nextLong()), 50));
+                node.addChild(new DemoNode(node, "N13N12N12", "C13", new Date(r.nextLong()), 60));
+                node.addChild(new DemoNode(node, "N14N12N12", "C14", new Date(r.nextLong()), 70));
+                node.addChild(new DemoNode(node, "N15N12N12", "C15", new Date(r.nextLong()), 80));
+            } else {
+                node.addChild(new DemoNode(node, "N12N12N12", "C12", new Date(r.nextLong()), 10));
+                node.addChild(new DemoNode(node, "N13N12N12", "C13", new Date(r.nextLong()), 20));
+                node.addChild(new DemoNode(node, "N14N12N12", "C14", new Date(r.nextLong()), 30));
+                node.addChild(new DemoNode(node, "N15N12N12", "C15", new Date(r.nextLong()), 40));
+            }
+            root.addChild(node);
+        }
+        return root;
+    }
+
+    @Override
+    public String getTitle() {
+        return "TreeTable Demo";
+    }
+
+    protected static class DemoNode extends DefaultTreeTableNode {
+
+        public DemoNode(final TreeTableNode parent, final String name, final String capital,
+                        final Date declared, final Integer area) {
+            super(parent, new Object[]{name, capital, declared, area});
+        }
+    }
+
+    protected static class DemoModel extends DefaultTreeTableModel {
+        static protected String[] columnNames = {"TreeNode", "String", "Date", "Integer"};
+        static protected Class<?>[] columnTypes = {TreeTableModel.class, String.class, Date.class, Integer.class};
+
+        public DemoModel(final TreeTableNode rootNode) {
+            super(rootNode, columnNames);
+            setColumnClasses(columnTypes);
+            root = rootNode;
+        }
+    }
+}

utils/src/main/java/com/github/weisj/darklaf/util/PropertyUtil.java

@@ -31,6 +31,7 @@ import java.util.Objects;
 import java.util.stream.Collectors;
 
 import javax.swing.*;
+import javax.swing.border.Border;
 import javax.swing.plaf.UIResource;
 
 public class PropertyUtil {
@@ -51,6 +52,14 @@ public class PropertyUtil {
         }
     }
 
+    public static void installBorder(final JComponent component, final Border border) {
+        if (component == null) return;
+        Border b = component.getBorder();
+        if (b == null || b instanceof UIResource) {
+            component.setBorder(border);
+        }
+    }
+
     public static void installProperty(final JComponent c, final String key, final Object value) {
         if (c.getClientProperty(key) == null) {
             c.putClientProperty(key, value);