/*
 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package javax.swing.plaf.basic;

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;

import java.awt.*;

import java.io.Serializable;


ComboBox renderer

Warning:
Serialized objects of this class will not be compatible with
future Swing releases. The current serialization support is
appropriate for short term storage or RMI between applications running
the same version of Swing.  As of 1.4, support for long term storage
of all JavaBeans
has been added to the java.beans package. Please see XMLEncoder. 
Author:
Arnaud Weber/**
 * ComboBox renderer
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases. The current serialization support is
 * appropriate for short term storage or RMI between applications running
 * the same version of Swing.  As of 1.4, support for long term storage
 * of all JavaBeans
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @author Arnaud Weber
 */
@SuppressWarnings("serial") // Same-version serialization only
public class BasicComboBoxRenderer extends JLabel
implements ListCellRenderer<Object>, Serializable {

   
An empty Border. This field might not be used. To change the
Border used by this renderer directly set it using
the setBorder method.
/**
    * An empty <code>Border</code>. This field might not be used. To change the
    * <code>Border</code> used by this renderer directly set it using
    * the <code>setBorder</code> method.
    */
    protected static Border noFocusBorder = new EmptyBorder(1, 1, 1, 1);
    private static final Border SAFE_NO_FOCUS_BORDER = new EmptyBorder(1, 1, 1, 1);

    
Constructs a new instance of BasicComboBoxRenderer. /**
     * Constructs a new instance of {@code BasicComboBoxRenderer}.
     */
    public BasicComboBoxRenderer() {
        super();
        setOpaque(true);
        setBorder(getNoFocusBorder());
    }

    private static Border getNoFocusBorder() {
        if (System.getSecurityManager() != null) {
            return SAFE_NO_FOCUS_BORDER;
        } else {
            return noFocusBorder;
        }
    }

    public Dimension getPreferredSize() {
        Dimension size;

        if (this.getText() == null || this.getText().isEmpty()) {
            setText( " " );
            size = super.getPreferredSize();
            setText( "" );
        }
        else {
            size = super.getPreferredSize();
        }

        return size;
    }

    @Override
    public Component getListCellRendererComponent(JList<?> list,
                                                 Object value,
                                                 int index,
                                                 boolean isSelected,
                                                 boolean cellHasFocus)
    {

        /**if (isSelected) {
            setBackground(UIManager.getColor("ComboBox.selectionBackground"));
            setForeground(UIManager.getColor("ComboBox.selectionForeground"));
        } else {
            setBackground(UIManager.getColor("ComboBox.background"));
            setForeground(UIManager.getColor("ComboBox.foreground"));
        }**/

        if (isSelected) {
            setBackground(list.getSelectionBackground());
            setForeground(list.getSelectionForeground());
        }
        else {
            setBackground(list.getBackground());
            setForeground(list.getForeground());
        }

        setFont(list.getFont());

        if (value instanceof Icon) {
            setIcon((Icon)value);
        }
        else {
            setText((value == null) ? "" : value.toString());
        }
        return this;
    }


    
A subclass of BasicComboBoxRenderer that implements UIResource.
BasicComboBoxRenderer doesn't implement UIResource
directly so that applications can safely override the
cellRenderer property with BasicListCellRenderer subclasses.

Warning:
Serialized objects of this class will not be compatible with
future Swing releases. The current serialization support is
appropriate for short term storage or RMI between applications running
the same version of Swing.  As of 1.4, support for long term storage
of all JavaBeans
has been added to the java.beans package. Please see XMLEncoder. /**
     * A subclass of BasicComboBoxRenderer that implements UIResource.
     * BasicComboBoxRenderer doesn't implement UIResource
     * directly so that applications can safely override the
     * cellRenderer property with BasicListCellRenderer subclasses.
     * <p>
     * <strong>Warning:</strong>
     * Serialized objects of this class will not be compatible with
     * future Swing releases. The current serialization support is
     * appropriate for short term storage or RMI between applications running
     * the same version of Swing.  As of 1.4, support for long term storage
     * of all JavaBeans
     * has been added to the <code>java.beans</code> package.
     * Please see {@link java.beans.XMLEncoder}.
     */
    @SuppressWarnings("serial") // Same-version serialization only
    public static class UIResource extends BasicComboBoxRenderer implements javax.swing.plaf.UIResource {
        
Constructs a UIResource. /**
         * Constructs a {@code UIResource}.
         */
        public UIResource() {}
    }
}