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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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*
* http://www.apache.org/licenses/LICENSE-2.0
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* KIND, either express or implied. See the License for the
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package org.apache.cayenne.modeler.util;
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import javax.swing.AbstractListModel;
import javax.swing.DefaultListCellRenderer;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JViewport;
import javax.swing.ListCellRenderer;
import javax.swing.ListSelectionModel;
import javax.swing.border.Border;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreePath;
/**
* A simple non-editable tree browser with multiple columns
* for display and navigation of a tree structure. This type of
* browser is ideal for showing deeply (or infinitely) nested
* trees/graphs. The most famous example of its use is Mac OS X
* Finder column view.
*
* <p>
* MultiColumnBrowser starts at the root of the tree
* and automatically expands to the right as navigation goes deeper.
* MultiColumnBrowser uses the same TreeModel as a regular JTree
* for its navigation model.
* </p>
*
* <p>
* Users are notified of selection changes via a TreeSelectionEvents.
* </p>
*
* @since 1.1
* @author Andrei Adamchik
*/
public class MultiColumnBrowser extends JPanel {
private static final ImageIcon rightArrow =
ModelerUtil.buildIcon("scroll_right.gif");
public static final int DEFAULT_MIN_COLUMNS_COUNT = 3;
protected int minColumns;
protected ListCellRenderer renderer;
protected TreeModel model;
protected Object[] selectionPath;
protected Dimension preferredColumnSize;
private List columns;
private ListSelectionListener browserSelector;
private List treeSelectionListeners;
public MultiColumnBrowser() {
this(DEFAULT_MIN_COLUMNS_COUNT);
}
public MultiColumnBrowser(int minColumns) {
if (minColumns < DEFAULT_MIN_COLUMNS_COUNT) {
throw new IllegalArgumentException(
"Expected "
+ DEFAULT_MIN_COLUMNS_COUNT
+ " or more columns, got: "
+ minColumns);
}
this.minColumns = minColumns;
this.browserSelector = new PanelController();
this.treeSelectionListeners = Collections.synchronizedList(new ArrayList());
initView();
}
public void addTreeSelectionListener(TreeSelectionListener listener) {
synchronized (treeSelectionListeners) {
if (listener != null && !treeSelectionListeners.contains(listener)) {
treeSelectionListeners.add(listener);
}
}
}
public void removeTreeSelectionListener(TreeSelectionListener listener) {
synchronized (treeSelectionListeners) {
treeSelectionListeners.remove(listener);
}
}
/**
* Notifies listeners of a tree selection change.
*/
protected void fireTreeSelectionEvent(Object[] selectionPath) {
TreeSelectionEvent e =
new TreeSelectionEvent(this, new TreePath(selectionPath), false, null, null);
synchronized (treeSelectionListeners) {
Iterator it = treeSelectionListeners.iterator();
while (it.hasNext()) {
TreeSelectionListener listener = (TreeSelectionListener) it.next();
listener.valueChanged(e);
}
}
}
/**
* Returns current selection path or null if no selection is made.
*/
public TreePath getSelectionPath() {
return new TreePath(selectionPath);
}
/**
* Returns the minumum number of displayed columns.
*/
public int getMinColumns() {
return minColumns;
}
/**
* Sets the minumum number of displayed columns.
*/
public void setMinColumns(int minColumns) {
this.minColumns = minColumns;
}
/**
* Returns prefrred size of a single browser column.
*/
public Dimension getPreferredColumnSize() {
return preferredColumnSize;
}
public void setPreferredColumnSize(Dimension preferredColumnSize) {
this.preferredColumnSize = preferredColumnSize;
refreshPreferredSize();
}
/**
* Resets currently used renderer to default one that will
* use the "name" property of objects and display a small
* arrow to the right of all non-leaf nodes.
*/
public void setDefaultRenderer() {
if (!(renderer instanceof MultiColumnBrowserRenderer)) {
setRenderer(new MultiColumnBrowserRenderer());
}
}
/**
* Returns ListCellRenderer for individual elements of each column.
*/
public ListCellRenderer getRenderer() {
return renderer;
}
/**
* Initializes the renderer of column cells.
*/
public synchronized void setRenderer(ListCellRenderer renderer) {
if (this.renderer != renderer) {
this.renderer = renderer;
// update existing browser
if (columns != null && columns.size() > 0) {
Iterator it = columns.iterator();
while (it.hasNext()) {
JList column = (JList) it.next();
column.setCellRenderer(renderer);
}
}
}
}
/**
* Initializes browser model.
*/
public synchronized void setModel(TreeModel model) {
if (model == null) {
throw new NullPointerException("Null tree model.");
}
if (this.model != model) {
this.model = model;
// display first column
updateFromModel(model.getRoot(), -1);
}
}
/**
* Returns browser model.
*/
public TreeModel getModel() {
return model;
}
/**
* Returns a current number of columns.
*/
public int getColumnsCount() {
return columns.size();
}
// ====================================================
// Internal private methods
// ====================================================
private void initView() {
columns = Collections.synchronizedList(new ArrayList(minColumns));
adjustViewColumns(minColumns);
}
/**
* Expands or contracts the view by <code>delta</code> columns.
* Never contracts the view below <code>minColumns</code>.
*/
private void adjustViewColumns(int delta) {
if (delta == 0) {
return;
}
setLayout(new GridLayout(1, columns.size() + delta, 3, 3));
if (delta > 0) {
for (int i = 0; i < delta; i++) {
appendColumn();
}
}
else {
for (int i = -delta; i > 0 && columns.size() > minColumns; i--) {
removeLastColumn();
}
}
refreshPreferredSize();
revalidate();
}
private BrowserPanel appendColumn() {
BrowserPanel panel = new BrowserPanel();
panel.addListSelectionListener(browserSelector);
panel.setCellRenderer(renderer);
columns.add(panel);
JScrollPane scroller =
new JScrollPane(
panel,
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
// note - it is important to set prefrred size on scroller,
// not on the component itself... otherwise resizing
// will be very ugly...
if (preferredColumnSize != null) {
scroller.setPreferredSize(preferredColumnSize);
}
add(scroller);
return panel;
}
private BrowserPanel removeLastColumn() {
if (columns.size() == 0) {
return null;
}
int index = columns.size() - 1;
BrowserPanel panel = (BrowserPanel) columns.remove(index);
panel.removeListSelectionListener(browserSelector);
// remove ansestor of the column (JScrollPane)
remove(index);
return panel;
}
/**
* Refreshes preferred size of the browser to
* reflect current number of columns.
*/
private void refreshPreferredSize() {
if (preferredColumnSize != null) {
int w = getColumnsCount() * (preferredColumnSize.width + 3) + 3;
int h = preferredColumnSize.height + 6;
setPreferredSize(new Dimension(w, h));
}
}
/**
* Makes numbered column visible if the browser parent allows scrolling.
*/
private void scrollToColumn(int column) {
if (getParent() instanceof JViewport) {
JViewport viewport = (JViewport) getParent();
// find a rectangle in the middle of the browser
// and scroll it...
double x = getWidth() * column / ((double) getMinColumns());
double y = getHeight() / 2;
if (preferredColumnSize != null) {
x -= preferredColumnSize.width / 2;
if (x < 0) {
x = 0;
}
}
Rectangle rectangle = new Rectangle((int) x, (int) y, 1, 1);
// Scroll the area into view.
viewport.scrollRectToVisible(rectangle);
}
}
/**
* Rebuilds view for the new object selection.
*/
private synchronized void updateFromModel(Object selectedNode, int panelIndex) {
if(selectionPath == null) {
selectionPath = new Object[0];
}
// clean up extra columns
int lastIndex = selectionPath.length;
// check array range to handle race conditions
for (int i = panelIndex + 1;
i <= lastIndex && i >= 0 && i < columns.size();
i++) {
BrowserPanel column = (BrowserPanel) columns.get(i);
column.getSelectionModel().clearSelection();
column.setRootNode(null);
}
// build path to selected node
this.selectionPath = rebuildPath(selectionPath, selectedNode, panelIndex);
// a selectedNode is contained in "panelIndex" column,
// but its children are in the next column.
panelIndex++;
// expand/contract columns as needed
adjustViewColumns(panelIndex + 1 - columns.size());
// selectedNode becomes the root of columns[panelIndex]
if (!model.isLeaf(selectedNode)) {
BrowserPanel lastPanel = (BrowserPanel) columns.get(panelIndex);
lastPanel.setRootNode(selectedNode);
scrollToColumn(panelIndex);
}
fireTreeSelectionEvent(selectionPath);
}
/**
* Builds a TreePath to the new node, that is known to be a peer or a child
* of one of the path components. As the method walks the current path backwards,
* it cleans columns that are not common with the new path.
*/
private Object[] rebuildPath(Object[] path, Object node, int panelIndex) {
Object[] newPath = new Object[panelIndex + 2];
System.arraycopy(path, 0, newPath, 0, panelIndex + 1);
newPath[panelIndex + 1] = node;
return newPath;
}
// ====================================================
// Helper classes
// ====================================================
// ====================================================
// Represents a browser column list model. This is an
// adapter on top of the TreeModel node, showing the branch
// containing node children
// ====================================================
final class ColumnListModel extends AbstractListModel {
Object treeNode;
int children;
void setTreeNode(Object treeNode) {
int oldChildren = children;
this.treeNode = treeNode;
this.children = (treeNode != null) ? model.getChildCount(treeNode) : 0;
// must fire an event to refresh the view
super.fireContentsChanged(
MultiColumnBrowser.this,
0,
Math.max(oldChildren, children));
}
public Object getElementAt(int index) {
return model.getChild(treeNode, index);
}
public int getSize() {
return children;
}
}
// ====================================================
// Represents a single browser column
// ====================================================
final class BrowserPanel extends JList {
BrowserPanel() {
BrowserPanel.this.setModel(new ColumnListModel());
BrowserPanel.this.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
}
void setRootNode(Object node) {
((ColumnListModel) BrowserPanel.this.getModel()).setTreeNode(node);
}
Object getTreeNode() {
return ((ColumnListModel) BrowserPanel.this.getModel()).treeNode;
}
}
// ====================================================
// Processes selection events in each column
// ====================================================
final class PanelController implements ListSelectionListener {
public void valueChanged(ListSelectionEvent e) {
// ignore "adjusting"
if (!e.getValueIsAdjusting()) {
BrowserPanel panel = (BrowserPanel) e.getSource();
Object selectedNode = panel.getSelectedValue();
// ignore unselected
if (selectedNode != null) {
updateFromModel(selectedNode, columns.indexOf(panel));
}
}
}
}
// ====================================================
// Default renderer that shows non-leaf nodes with a
// small right arrow. Unfortunately we can't subclass
// DefaultListCellRenerer since it extends JLabel that
// does not allow the layout that we need.
// ====================================================
final class MultiColumnBrowserRenderer implements ListCellRenderer, Serializable {
ListCellRenderer leafRenderer;
JPanel nonLeafPanel;
ListCellRenderer nonLeafTextRenderer;
MultiColumnBrowserRenderer() {
leafRenderer = CellRenderers.listRenderer();
nonLeafTextRenderer = new DefaultListCellRenderer() {
public Border getBorder() {
return null;
}
};
nonLeafPanel = new JPanel();
nonLeafPanel.setLayout(new BorderLayout());
nonLeafPanel.add(new JLabel(rightArrow), BorderLayout.EAST);
nonLeafPanel.add((Component) nonLeafTextRenderer, BorderLayout.WEST);
}
public Component getListCellRendererComponent(
JList list,
Object value,
int index,
boolean isSelected,
boolean cellHasFocus) {
if (getModel().isLeaf(value)) {
return leafRenderer.getListCellRendererComponent(
list,
value,
index,
isSelected,
cellHasFocus);
}
Object renderedValue = ModelerUtil.getObjectName(value);
if (renderedValue == null) {
// render NULL as empty string
renderedValue = " ";
}
Component text =
nonLeafTextRenderer.getListCellRendererComponent(
list,
renderedValue,
index,
isSelected,
cellHasFocus);
nonLeafPanel.setComponentOrientation(text.getComponentOrientation());
nonLeafPanel.setBackground(text.getBackground());
nonLeafPanel.setForeground(text.getForeground());
nonLeafPanel.setEnabled(text.isEnabled());
return nonLeafPanel;
}
}
}