import java.util.HashSet;

import java.util.Set;

import org.eclipse.core.runtime.IConfigurationElement;

import org.eclipse.core.runtime.IExtension;

import org.eclipse.core.runtime.IExtensionPoint;

import org.eclipse.core.runtime.Platform;

import org.eclipse.jface.viewers.ViewerFilter;

import org.eclipse.mylyn.internal.context.ui.ContextUiPlugin;

import org.eclipse.ui.internal.ide.IDEWorkbenchPlugin;

import org.eclipse.ui.views.navigator.ResourcePatternFilter;

	private Set<String> getPreservedFilterPatterns() {

		IExtensionPoint extension = Platform.getExtensionRegistry().getExtensionPoint(

				IDEWorkbenchPlugin.IDE_WORKBENCH + '.' + "resourceFilters");

		Set<String> preservedIds = ContextUiPlugin.getDefault().getPreservedFilterIds(viewPart.getSite().getId());

		Set<String> filters = new HashSet<String>();

		if (extension != null) {

			IExtension[] extensions = extension.getExtensions();

			for (IExtension extension2 : extensions) {

				IConfigurationElement[] configElements = extension2.getConfigurationElements();

				if (extension2.getUniqueIdentifier() != null && preservedIds.contains(extension2.getUniqueIdentifier())) {

					for (IConfigurationElement configElement : configElements) {

						String pattern = configElement.getAttribute("pattern");//$NON-NLS-1$

						if (pattern != null) {

							filters.add(pattern);

						}

						String selected = configElement.getAttribute("selected");//$NON-NLS-1$

						if (selected != null && selected.equalsIgnoreCase("true")) { //$NON-NLS-1$

							//defaultFilters.add(pattern);

						}

					}

				}

			}

		}

		return filters;

	}

	@Override

	protected boolean isPreservedFilter(ViewerFilter filter) {

		if (filter instanceof ResourcePatternFilter) {

			Set<String> preservedFilterPatterns = getPreservedFilterPatterns();

			//NOTE: since the resource filters are all contained in one filter, if one is preserved, then we preserve all filters

			for (String pattern : ((ResourcePatternFilter) filter).getPatterns()) {

				if (preservedFilterPatterns.contains(pattern)) {

					return true;

				}

			}

			return true;

		}

		return super.isPreservedFilter(filter);

	}