| /******************************************************************************* |
| * Copyright (c) 2005, 2012 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 Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.bpel.ui.details.providers; |
| |
| import org.eclipse.jface.viewers.Viewer; |
| import org.eclipse.jface.viewers.ViewerFilter; |
| |
| /** |
| * Filter which adds null to the beginning of the list of objects. This is used to show |
| * a "none" placeholder in combo boxes. |
| * |
| * TODO: this might be incompatible with filters that aren't expecting null to appear as |
| * a model object. We don't use any filters yet though. |
| */ |
| public class AddNullFilter extends ViewerFilter { |
| |
| // note: clients should use AddNullFilter.getInstance() |
| protected AddNullFilter() { |
| } |
| |
| @Override |
| public Object[] filter(Viewer viewer, Object parent, Object[] elements) { |
| Object[] result = new Object[elements.length + 1]; |
| result[0] = null; |
| System.arraycopy(elements, 0, result, 1, elements.length); |
| return result; |
| } |
| @Override |
| public boolean select(Viewer viewer, Object parentElement, Object element) { |
| return true; |
| } |
| |
| protected static AddNullFilter instance; |
| public static AddNullFilter getInstance() { |
| if (instance == null) instance = new AddNullFilter(); |
| return instance; |
| } |
| } |
