SimpleTreeCellRenderer.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.uitools.cell;

import java.awt.Component;

import javax.swing.Icon;
import javax.swing.JTree;
import javax.swing.tree.DefaultTreeCellRenderer;

/**
 * This renderer should behave the same as the DefaultTreeCellRenderer;
 * but it slightly refactors the calculation of the icon and text of the tree
 * cell so that subclasses can easily override the methods that build
 * the icon and text.
 *
 * In most cases, you need only override:
 *     #buildIcon(Object value)
 *     #buildText(Object value)
 */
public class SimpleTreeCellRenderer
    extends DefaultTreeCellRenderer
{

    /**
     * Construct a simple renderer.
     */
    public SimpleTreeCellRenderer() {
        super();
    }

    /**
     * @see javax.swing.tree.DefaultTreeCellRenderer#getTreeCellRendererComponent(javax.swing.JTree, Object, boolean, boolean, boolean, int, boolean)
     */
    public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean cellHasFocus) {
        // substitute null for the cell value so an empty string is used for the text...
        super.getTreeCellRendererComponent(tree, null, sel, expanded, leaf, row, cellHasFocus);

        // ...then set the icon and text manually
        this.setIcon(this.buildIcon(tree, value, sel, expanded, leaf, row, cellHasFocus));
        this.setText(this.buildText(tree, value, sel, expanded, leaf, row, cellHasFocus));

        this.setToolTipText(this.buildToolTipText(tree, value, sel, expanded, leaf, row, cellHasFocus));

        // the context will be initialized only if a reader is running
        if (this.accessibleContext != null) {
            this.accessibleContext.setAccessibleName(this.buildAccessibleName(tree, value, sel, expanded, leaf, row, cellHasFocus));
        }

        return this;
    }

    /**
     * Return the icon representation of the specified cell
     * value and other settings. (Even more settings are
     * accessible via inherited getters: hasFocus, isEnabled, etc.)
     */
    protected Icon buildIcon(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean cellHasFocus) {
        return this.buildIcon(value);
    }

    /**
     * Return the icon representation of the specified cell
     * value. The default is to display the icon already calculated
     * by the DefaultTreeCellRenderer (which ignores the cell value).
     */
    protected Icon buildIcon(Object value) {
        // replicate the default behavior by simply returning the icon that
        // was already calculated by the superclass (irrespective of the cell value);
        // this is a bit hackish - but the default renderer is not very well factored...  ~bjv
        return this.getIcon();
    }

    /**
     * Return the textual representation of the specified cell
     * value and other settings. (Even more settings are
     * accessible via inherited getters: hasFocus, isEnabled, etc.)
     */
    protected String buildText(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean cellHasFocus) {
        return this.buildText(value);
    }

    /**
     * Return the textual representation of the specified cell
     * value. The default is to display the object's default string
     * representation (as returned by #toString()).
     */
    protected String buildText(Object value) {
        return (value == null) ? "" : value.toString();
    }

    /**
     * Return the text displayed when the cursor lingers over the specified cell.
     * (Even more settings are accessible via inherited getters: hasFocus, isEnabled, etc.)
     */
    protected String buildToolTipText(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean cellHasFocus) {
        return this.buildToolTipText(value);
    }

    /**
     * Return the text displayed when the cursor lingers over the specified cell.
     */
    protected String buildToolTipText(Object value) {
        return null;
    }

    /**
     * Returns a string that can add more description to the rendered object when
     * the text is not sufficient, if <code>null</code> is returned, then the
     * text is used as the accessible text.
     */
    protected String buildAccessibleName(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean cellHasFocus) {
        return this.buildAccessibleName(value);
    }

    /**
     * Returns a string that can add more description to the rendered object when
     * the text is not sufficient, if <code>null</code> is returned, then the
     * text is used as the accessible text.
     */
    protected String buildAccessibleName(Object value) {
        return null;
    }

}