RidgetToStatuslineSubscriber.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.ridgets;

import java.util.Collection;

import org.eclipse.riena.core.util.RienaConfiguration;
import org.eclipse.riena.ui.ridgets.marker.StatuslineMessageMarkerViewer;

/**
 * @since 5.0
 */
public class RidgetToStatuslineSubscriber {

	public static final String SHOW_RIDGET_MESSAGES_IN_STATUSLINE_KEY = RienaConfiguration.SHOW_RIDGET_MESSAGES_IN_STATUSLINE_KEY;

	private StatuslineMessageMarkerViewer messageViewer;

	/**
	 * @param ridget
	 */
	public void addRidget(final IRidget ridget) {
		setStatuslineViewerForRidget(ridget, messageViewer);
	}

	/**
	 * @param ridget
	 */
	public void removeRidget(final IRidget ridget) {
		removeStatuslineViewerForRidget(ridget, messageViewer);
	}

	/**
	 * Set the {@link IStatuslineRidget} which should display the marker messages of the given ridgets. If a status line ridget is already set, it will be
	 * "unsubscribed" from the marker messages. Only one status line ridget can be set up to display these messages. If <code>null</code> is passed, the marker
	 * messages will not be displayed on any status line (that may be set before).
	 */
	public void setStatuslineToShowMarkerMessages(final IStatuslineRidget statusline, final Collection<? extends IRidget> ridgets) {
		if (!isDifferentStatusline(statusline)) {
			return;
		}

		final StatuslineMessageMarkerViewer newMessageViewer = createMessageViewer(statusline);
		for (final IRidget r : ridgets) {
			removeStatuslineViewerForRidget(r, messageViewer);
			if (newMessageViewer != null) {
				setStatuslineViewerForRidget(r, newMessageViewer);
			}
		}
		messageViewer = newMessageViewer;
	}

	/**
	 * visible for testing
	 */
	protected StatuslineMessageMarkerViewer createMessageViewer(final IStatuslineRidget statusline) {
		return statusline != null ? new StatuslineMessageMarkerViewer(statusline) : null;
	}

	/**
	 * visible for testing
	 * 
	 * @return checks if the given status line is different than the one we are holding
	 */
	public boolean isDifferentStatusline(final IStatuslineRidget statuslineToShowMarkerMessages) {
		return messageViewer == null && statuslineToShowMarkerMessages != null || messageViewer != null
				&& messageViewer.getStatusLine() != statuslineToShowMarkerMessages;
	}

	private void removeStatuslineViewerForRidget(final IRidget ridget, final StatuslineMessageMarkerViewer messageViewer) {
		if (ridget == null || messageViewer == null) {
			return;
		}
		if (ridget instanceof IRidgetContainer) {
			((IRidgetContainer) ridget).setStatuslineToShowMarkerMessages(null);
		} else if (ridget instanceof IBasicMarkableRidget) {
			messageViewer.removeRidget((IBasicMarkableRidget) ridget);
		}
	}

	private void setStatuslineViewerForRidget(final IRidget ridget, final StatuslineMessageMarkerViewer messageViewer) {
		if (messageViewer == null || ridget == null) {
			return;
		}
		if (ridget instanceof IRidgetContainer) {
			((IRidgetContainer) ridget).setStatuslineToShowMarkerMessages(messageViewer.getStatusLine());
		} else if (ridget instanceof IBasicMarkableRidget) {
			messageViewer.addRidget((IBasicMarkableRidget) ridget);
		}
	}
}