org.fife.ui.autocomplete.Util Maven / Gradle / Ivy

Go to download
/*
 * 12/21/2008
 *
 * Util.java - Utility methods for the autocompletion package.
 * Copyright (C) 2008 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.autocomplete;

import java.awt.Color;
import java.lang.reflect.Method;
import java.net.URI;


/**
 * Utility methods for the autocomplete framework.
 *
 * @author Robert Futrell
 * @version 1.0
 */
class Util {

	private static boolean desktopCreationAttempted;
	private static Object desktop;
	private static final Object LOCK_DESKTOP_CREATION = new Object();


	/**
	 * Returns a hex string for the specified color, suitable for HTML.
	 *
	 * @param c The color.
	 * @return The string representation, in the form "#rrggbb",
	 *         or null if c is null.
	 */
	public static String getHexString(Color c) {

		if (c==null) {
			return null;
		}

		StringBuffer sb = new StringBuffer("#");
		int r = c.getRed();
		if (r<16) {
			sb.append('0');
		}
		sb.append(Integer.toHexString(r));
		int g = c.getGreen();
		if (g<16) {
			sb.append('0');
		}
		sb.append(Integer.toHexString(g));
		int b = c.getBlue();
		if (b<16) {
			sb.append('0');
		}
		sb.append(Integer.toHexString(b));

		return sb.toString();

	}


	/**
	 * Attempts to open a web browser to the specified URI.
	 *
	 * @param uri The URI to open.  If this is null, nothing
	          happens and this method returns false.
	 * @return Whether the operation was successful.  This will be
	 *         false on JRE's older than 1.6.
	 */
	public static boolean browse(URI uri) {

		boolean success = false;

		if (uri!=null) {
			Object desktop = getDesktop();
			if (desktop!=null) {
				try {
					Method m = desktop.getClass().getDeclaredMethod(
								"browse", new Class[] { URI.class });
					m.invoke(desktop, new Object[] { uri });
					success = true;
				} catch (RuntimeException re) {
					throw re; // Keep FindBugs happy
				} catch (Exception e) {
					// Ignore, just return "false" below.
				}
			}
		}

		return success;

	}


	/**
	 * Returns the singleton java.awt.Desktop instance, or
	 * null if it is unsupported on this platform (or the JRE
	 * is older than 1.6).
	 *
	 * @return The desktop, as an {@link Object}.
	 */
	private static Object getDesktop() {

		synchronized (LOCK_DESKTOP_CREATION) {

			if (!desktopCreationAttempted) {

				desktopCreationAttempted = true;

				try {
					Class desktopClazz = Class.forName("java.awt.Desktop");
					Method m = desktopClazz.
						getDeclaredMethod("isDesktopSupported", null);

					boolean supported = ((Boolean)m.invoke(null, null)).
												booleanValue();
					if (supported) {
						m = desktopClazz.getDeclaredMethod("getDesktop", null);
						desktop = m.invoke(null, null);
					}

				} catch (RuntimeException re) {
					throw re; // Keep FindBugs happy
				} catch (Exception e) {
					// Ignore; keeps desktop as null.
				}

			}

		}

		return desktop;

	}


}