ChecklistTreeCellRenderer.java

package net.vhati.modmanager.ui.tree;

import java.awt.BorderLayout;
import java.awt.Component;
import javax.swing.JPanel;
import javax.swing.JTree;
import javax.swing.tree.TreeCellRenderer;
import javax.swing.tree.TreePath;

import net.vhati.modmanager.ui.tree.ChecklistTreePathFilter;
import net.vhati.modmanager.ui.tree.ChecklistTreeSelectionModel;
import net.vhati.modmanager.ui.tree.TristateCheckBox;
import net.vhati.modmanager.ui.tree.TristateButtonModel.TristateState;


/**
 * A cell renderer that augments an existing renderer with a checkbox.
 */
public class ChecklistTreeCellRenderer extends JPanel implements TreeCellRenderer {

	protected ChecklistTreeSelectionModel selectionModel;
	protected ChecklistTreePathFilter checklistFilter;
	protected TreeCellRenderer delegate;
	protected TristateCheckBox checkbox = new TristateCheckBox();
	protected int checkMaxX = 0;


	/**
	 * Constructor.
	 *
	 * @param delegate  a traditional TreeCellRenderer
	 * @param selectionModel  a model to query for checkbox states
	 * @param checklistFilter  a TreePath filter, or null to always show a checkbox
	 */
	public ChecklistTreeCellRenderer( TreeCellRenderer delegate, ChecklistTreeSelectionModel selectionModel, ChecklistTreePathFilter checklistFilter ) {
		super();
		this.delegate = delegate;
		this.selectionModel = selectionModel;
		this.checklistFilter = checklistFilter;

		this.setLayout( new BorderLayout() );
		this.setOpaque( false );
		checkbox.setOpaque( false );

		checkMaxX = checkbox.getPreferredSize().width;
	}


	@Override
	public Component getTreeCellRendererComponent( JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean hasFocus ) {
		this.removeAll();
		checkbox.setState( TristateState.DESELECTED );

		Component delegateComp = delegate.getTreeCellRendererComponent( tree, value, sel, expanded, leaf, row, hasFocus );

		TreePath path = tree.getPathForRow( row );
		if ( path != null ) {
			if ( selectionModel.isPathSelected( path, selectionModel.isDigged() ) ) {
				checkbox.setState( TristateState.SELECTED );
			} else {
				checkbox.setState( ( selectionModel.isDigged() && selectionModel.isPartiallySelected( path ) ) ? TristateState.INDETERMINATE : TristateState.DESELECTED );
			}
		}
		checkbox.setVisible( path == null || checklistFilter == null || checklistFilter.isSelectable( path ) );
		checkbox.setEnabled( tree.isEnabled() );

		this.add( checkbox, BorderLayout.WEST );
		this.add( delegateComp, BorderLayout.CENTER );
		return this;
	}


	public void setDelegate( TreeCellRenderer delegate ) {
		this.delegate = delegate;
	}

	public TreeCellRenderer getDelegate() {
		return delegate;
	}


	/**
	 * Returns the checkbox's right edge (in the renderer component's coordinate space).
	 *
	 * Values less than that can be interpreted as within the checkbox's bounds.
	 * X=0 is the renderer component's left edge.
	 */
	public int getCheckboxMaxX() {
		return checkMaxX;
	}
}