org.eclipse.mylyn.context.ui/src/org/eclipse/mylyn/ui/internal/BrowseFilteredListener.java

/*******************************************************************************
 * Copyright (c) 2004 - 2005 University Of British Columbia 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:
 *     University Of British Columbia - initial API and implementation
 *******************************************************************************/

package org.eclipse.mylar.ui.internal;

import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.StructuredViewer;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.jface.viewers.ViewerFilter;
import org.eclipse.mylar.ui.InterestFilter;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.events.KeyListener;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.MouseListener;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.Tree;

/**
 * @author Mik Kersten
 */
public class BrowseFilteredListener implements MouseListener, KeyListener {
	
	private StructuredViewer viewer;
	
	public BrowseFilteredListener(StructuredViewer viewer) {
		this.viewer = viewer;
	}
	
	public void keyPressed(KeyEvent event) {
		final InterestFilter filter = getFilter(viewer);
		if (filter == null) return;
		if (keyboardInteractionAccepted(event)) {
			if (viewer instanceof TreeViewer) {
				final TreeViewer treeViewer = (TreeViewer)viewer;
				ISelection selection = treeViewer.getSelection();
				if (selection instanceof IStructuredSelection) {
					Object targetObject = ((IStructuredSelection)selection).getFirstElement();
					unfilter(filter, treeViewer, targetObject);
				} 
			} 
		} else {
			filter.resetTemporarilyUnfiltered();
		}
	}

	private void unfilter(final InterestFilter filter, final TreeViewer treeViewer, Object targetObject) {
		if (targetObject != null) {
			filter.setTemporarilyUnfiltered(targetObject);
			treeViewer.refresh(targetObject, true);
			treeViewer.expandToLevel(targetObject, 2);
		}
	}

	public void keyReleased(KeyEvent e) {
		// TODO Auto-generated method stub
		
	}
	
	public void mouseDown(MouseEvent event) {
		final InterestFilter filter = getFilter(viewer);
		if (filter == null) return;
		if (mouseInteractionAccepted(event)) {
			if (viewer instanceof TreeViewer) {
				final TreeViewer treeViewer = (TreeViewer)viewer;
				ISelection selection = treeViewer.getSelection();
				if (selection instanceof IStructuredSelection) {
					Object targetObject = null;
					if (getClickedItem(event) != null) {
						targetObject = ((IStructuredSelection)selection).getFirstElement();
					} else if (treeViewer.getTree().getTopItem() != null) {
						targetObject = treeViewer.getTree().getTopItem().getData();
					}
					unfilter(filter, treeViewer, targetObject);
				} 
			} 
		} else {
			filter.resetTemporarilyUnfiltered();
		}
    }

	private Object getClickedItem(MouseEvent event) {
		if (event.getSource() instanceof Table) {
			return ((Table)event.getSource()).getItem(new Point(event.x, event.y));
		} else if (event.getSource() instanceof Tree) {
			return ((Tree)event.getSource()).getItem(new Point(event.x, event.y));
		}
		return null;		
	}

	private boolean mouseInteractionAccepted(MouseEvent event) {
		return (event.stateMask & SWT.ALT) != 0;
	}

	private boolean keyboardInteractionAccepted(KeyEvent event) {
		return event.keyCode == SWT.ARROW_RIGHT;
	}
	
	private InterestFilter getFilter(StructuredViewer structuredViewer) {
		ViewerFilter[] filters = structuredViewer.getFilters();
		for (int i = 0; i < filters.length; i++) {
			if (filters[i] instanceof InterestFilter) return (InterestFilter)filters[i];
		}
		return null;
	}

	public void mouseUp(MouseEvent e) { }

	public void mouseDoubleClick(MouseEvent e) { }

}