DMDirc-Plugins/ui_swing/src/main/java/com/dmdirc/addons/ui_swing/components/renderers/DMDircListCellRenderer.java

/*
 * Copyright (c) 2006-2017 DMDirc Developers
 *
 * 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.dmdirc.addons.ui_swing.components.renderers;

import java.awt.Component;

import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.ListCellRenderer;

/**
 * Simplifies implementing a cell renderer, works around oddities in look and feels.
 *
 * @param <E> the type of values this renderer can be used for
 */
public abstract class DMDircListCellRenderer<E> implements ListCellRenderer<E> {

    /**
     * A version number for this class.
     */
    private static final long serialVersionUID = 1;
    /**
     * Parent cell renderer.
     */
    private final ListCellRenderer<? super E> parentRenderer;
    /**
     * Label to use if parent doesn't supply one.
     */
    private JLabel label;

    public DMDircListCellRenderer(final ListCellRenderer<? super E> parentRenderer) {
        this.parentRenderer = parentRenderer;
    }

    /**
     * Renders the cell on the given label.
     *
     * @param label      Label to render
     * @param value      Object to render
     * @param index      Index of the cell in the list
     * @param isSelected Is the cell selected
     * @param hasFocus   Does the cell have focus
     */
    protected abstract void renderValue(final JLabel label, final E value,
            final int index, final boolean isSelected, final boolean hasFocus);

    @Override
    public Component getListCellRendererComponent(final JList<? extends E> list,
            final E value, final int index, final boolean isSelected, final boolean cellHasFocus) {
        final Component component = parentRenderer.getListCellRendererComponent(list, value,
                index, isSelected, cellHasFocus);
        if (component instanceof JLabel) {
            renderValue((JLabel) component, value, index, isSelected, cellHasFocus);
            return component;
        } else {
            if (label == null) {
                label = new JLabel();
            }
            renderValue(label, value, index, isSelected, cellHasFocus);
            return label;
        }
    }

}