ViewerFilterAction.java

/**
 * <copyright>
 *
 * Copyright (c) 2005, 2010 IBM Corporation 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: 
 *   IBM - Initial API and implementation
 *
 * </copyright>
 *
 * $Id: ViewerFilterAction.java,v 1.2 2006/12/28 06:42:02 marcelop Exp $
 */

package net.enilink.komma.common.ui.action;

import java.util.LinkedHashSet;
import java.util.Set;

import org.eclipse.jface.action.Action;
import org.eclipse.jface.viewers.StructuredViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerFilter;

/**
 * Action wrapper for a {@link ViewerFilter} that can be used in multiple
 * viewers.
 * 
 * @since 2.2.0
 */
public abstract class ViewerFilterAction extends Action {
	protected Set<Viewer> viewers;
	protected ViewerFilter viewerFilter;

	public ViewerFilterAction(String text, int style) {
		super(text, style);
		setId(Integer.toString(hashCode()));
	}

	public void addViewer(Viewer viewer) {
		if (viewer instanceof StructuredViewer) {
			if (viewers == null) {
				viewers = new LinkedHashSet<Viewer>();
			}

			if (viewers.add(viewer)) {
				if (viewerFilter == null) {
					viewerFilter = new ViewerFilter() {
						@Override
						public boolean select(Viewer viewer,
								Object parentElement, Object element) {
							return ViewerFilterAction.this.select(viewer,
									parentElement, element);
						}
					};
				}

				((StructuredViewer) viewer).addFilter(viewerFilter);
			}
		}
	}

	public void removeViewer(Viewer viewer) {
		if (viewers != null) {
			if (viewers.remove(viewer)) {
				if (!viewer.getControl().isDisposed()) {
					((StructuredViewer) viewer).removeFilter(viewerFilter);
				}
			}
		}
	}

	public void dispose() {
		if (viewers != null) {
			for (Viewer viewer : viewers) {
				if (!viewer.getControl().isDisposed()) {
					((StructuredViewer) viewer).removeFilter(viewerFilter);
				}
			}
			viewers.clear();
			viewers = null;
		}
		viewerFilter = null;
	}

	@Override
	public void setChecked(boolean checked) {
		boolean wasChecked = isChecked();
		super.setChecked(checked);
		if (wasChecked != checked) {
			refreshViewers();
		}
	}

	protected void refreshViewers() {
		if (viewers != null) {
			for (Viewer viewer : viewers) {
				if (!viewer.getControl().isDisposed()) {
					viewer.refresh();
				}
			}
		}
	}

	public abstract boolean select(Viewer viewer, Object parentElement,
			Object element);
}