Style.java

/*
 * 08/06/2004
 *
 * Style.java - A set of traits for a particular token type to use while
 * painting.
 * Copyright (C) 2004 Robert Futrell
 * robert_futrell at users.sourceforge.net
 * http://fifesoft.com/rsyntaxtextarea
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA.
 */
package org.fife.ui.rsyntaxtextarea;

import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import javax.swing.JPanel;

/**
 * The color and style information for a token type. Each token type in an <code>RSyntaxTextArea</code> has a
 * corresponding <code>Style</code>; this <code>Style</code> tells us the following things:
 * 
 * <ul>
 * <li>What foreground color to use for tokens of this type.</li>
 * <li>What background color to use.</li>
 * <li>The font to use.</li>
 * <li>Whether the token should be underlined.</li>
 * </ul>
 * 
 * @author Robert Futrell
 * @version 0.6
 */
public class Style implements Cloneable {

    public static final Color DEFAULT_FOREGROUND = Color.BLACK;
    public static final Color DEFAULT_BACKGROUND = null;
    public static final Font DEFAULT_FONT = null;

    public Color foreground;
    public Color background;
    public boolean underline;
    public Font font;

    FontMetrics fontMetrics;

    /**
     * Creates a new syntax scheme defaulting to black foreground, no background, and no styling.
     */
    public Style() {
        this(DEFAULT_FOREGROUND, DEFAULT_BACKGROUND);
    }

    /**
     * Creates a new syntax scheme with the specified colors and no styling.
     * 
     * @param fg
     *            The foreground color to use.
     * @param bg
     *            The background color to use.
     */
    public Style(Color fg, Color bg) {
        this(fg, bg, DEFAULT_FONT);
    }

    /**
     * Creates a new syntax scheme.
     * 
     * @param fg
     *            The foreground color to use.
     * @param bg
     *            The background color to use.
     * @param font
     *            The font for this syntax scheme.
     */
    public Style(Color fg, Color bg, Font font) {
        this(fg, bg, font, false);
    }

    /**
     * Creates a new syntax scheme.
     * 
     * @param fg
     *            The foreground color to use.
     * @param bg
     *            The background color to use.
     * @param font
     *            The font for this syntax scheme.
     * @param underline
     *            Whether or not to underline tokens with this style.
     */
    public Style(Color fg, Color bg, Font font, boolean underline) {
        foreground = fg;
        background = bg;
        this.font = font;
        this.underline = underline;
        this.fontMetrics = font == null ? null :
                new JPanel().getFontMetrics(font); // Default, no rendering hints!
    }

    /**
     * Returns whether or not two (possibly <code>null</code>) objects are equal.
     */
    private boolean areEqual(Object o1, Object o2) {
        return (o1 == null && o2 == null) || (o1 != null && o1.equals(o2));
    }

    /**
     * Returns a deep copy of this object.
     * 
     * @return The copy.
     */
    public Object clone() {
        Style clone = null;
        try {
            clone = (Style) super.clone();
        } catch (CloneNotSupportedException cnse) { // Never happens
            cnse.printStackTrace();
            return null;
        }
        clone.foreground = foreground;
        clone.background = background;
        clone.font = font;
        clone.underline = underline;
        clone.fontMetrics = fontMetrics;
        return clone;
    }

    /**
     * Returns whether or not two syntax schemes are equal.
     * 
     * @param o2
     *            The object with which to compare this syntax scheme.
     * @return Whether or not these two syntax schemes represent the same scheme.
     */
    public boolean equals(Object o2) {
        if (o2 instanceof Style) {
            Style ss2 = (Style) o2;
            if (this.underline == ss2.underline &&
                    areEqual(foreground, ss2.foreground) &&
                    areEqual(background, ss2.background) &&
                    areEqual(font, ss2.font) &&
                    areEqual(fontMetrics, ss2.fontMetrics))
                return true;
        }
        return false;
    }

    /**
     * Computes the hash code to use when adding this syntax scheme to hash tables.
     * <p>
     * 
     * This method is implemented, since {@link #equals(Object)} is implemented, to keep FindBugs happy.
     * 
     * @return The hash code.
     */
    public int hashCode() {
        int hashCode = underline ? 1 : 0;
        if (foreground != null) {
            hashCode ^= foreground.hashCode();
        }
        if (background != null) {
            hashCode ^= background.hashCode();
        }
        return hashCode;
    }

    /**
     * Returns a string representation of this style.
     * 
     * @return A string representation of this style.
     */
    public String toString() {
        return "[Style: foreground: " + foreground +
                ", background: " + background + ", underline: " +
                underline + ", font: " + font + "]";
    }

}