LnfManager.java

/*******************************************************************************
 * Copyright (c) 2007, 2014 compeople AG and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    compeople AG - initial API and implementation
 *******************************************************************************/
package org.eclipse.riena.ui.swt.lnf;

import javax.swing.Renderer;

import org.eclipse.swt.widgets.Display;

import org.eclipse.riena.core.singleton.SessionSingletonProvider;
import org.eclipse.riena.core.singleton.SingletonProvider;
import org.eclipse.riena.internal.ui.swt.lnf.LnfManagerInternal;
import org.eclipse.riena.ui.swt.lnf.renderer.EmbeddedTitlebarRenderer;
import org.eclipse.riena.ui.swt.lnf.rienadefault.RienaDefaultLnf;

/**
 * The {@code LnfManager} manages the current look and feel of the riena (navigation) widgets.
 * <p>
 * The {@code LnfManager} has the term of a default look-and-feel (L&F). The default L&F is initially set by Riena to {@code RienaDefaultLnf}. But the default
 * L&F may also be overridden by frameworks based on Riena. That allows them to define their own default L&F.
 * <p>
 * <b>Note:</b> Changing the L&F within a running application might result in system resources such as colors, fonts and images which will not be disposed.
 * <p>
 * However, applications can again override the default L&F. This can be done by either setting the system property "riena.lnf" or by specifying their L&F with
 * the methods {@code LnfManager.setLnf()}.
 * <p>
 * When specifying the L&F class via a string (either system property or one of the above mentioned methods) the string should conform to:
 * 
 * <pre>
 * lnf := [ Bundle-Symbolic-Name ":" ] LnF-Class-Name
 * </pre>
 * 
 * Where Bundle-Symbolic-Name allows to load the L&F class from the bundle with this symbolic name.<br>
 * If the Bundle-Symbolic-Name is omitted the {@code LnfManager} tries to load the Lnf class with the {LnfMangager}'s class loader.
 */
public final class LnfManager {

	/**
	 * Allows setting of an application L&F.
	 * 
	 * @since 1.2
	 */
	public static final String RIENA_LNF_SYSTEM_PROPERTY = "riena.lnf"; //$NON-NLS-1$

	/**
	 * The LnFManager has to be an SessionSingleton, because it he LnF that holds a Map of {@link Renderer}. The Renderer get passed a UIControl that was
	 * created with a {@link Display} from a specific user. Some Renderer like {@link EmbeddedTitlebarRenderer} keep the UIControl to redraw later.
	 */
	private final static SingletonProvider<LnfManagerInternal> LMI = new SessionSingletonProvider<LnfManagerInternal>(LnfManagerInternal.class);

	private LnfManager() {
		// cannot instantiated, because all methods are static
	}

	/**
	 * Set a new default look and feel. See class header JavaDoc for details.
	 * 
	 * @param defaultLnf
	 *            new default L&F
	 * @since 1.2
	 */
	public static void setDefaultLnf(final RienaDefaultLnf defaultLnf) {
		LMI.getInstance().setDefaultLnf(defaultLnf);
	}

	/**
	 * Set the new look and feel specified by the given class name (see class header JavaDoc).
	 * <p>
	 * <b>Note:</b> Changing the L&F in a running application might result in system resources such as colors, fonts and images which will not be disposed.
	 * 
	 * @param currentLnfClassName
	 *            a string specifying the name of the class that implements the look and feel
	 */
	public static void setLnf(final String currentLnfClassName) {
		LMI.getInstance().setLnf(currentLnfClassName);
	}

	/**
	 * Sets the new look and feel.
	 * <p>
	 * If this is set, it will override the default look and feel. See class header JavaDoc for details.
	 * <p>
	 * <b>Note:</b> Changing the L&F in a running application might result in system resources such as colors, fonts and images which will not be disposed.
	 * 
	 * @param currentLnf
	 *            new look and feel to install.
	 */
	public static synchronized void setLnf(final RienaDefaultLnf currentLnf) {
		LMI.getInstance().setLnf(currentLnf);
	}

	/**
	 * Returns the current look and feel. If no look and feel is set, the default look and feel is returned.
	 * 
	 * @return current look and feel
	 */
	public static RienaDefaultLnf getLnf() {
		return LMI.getInstance().getLnf();
	}

	/**
	 * Disposes (uninitializes) the current look and feel.
	 */
	public static void dispose() {
		LMI.getInstance().dispose();
	}

	/**
	 * @since 6.0
	 */
	public static boolean isLnfCreated() {
		return LMI.getInstance().isLnfCreated();
	}

}