1 /*******************************************************************************
2 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
4 * All rights reserved. This program and the accompanying materials
5 * are made available under the terms of the Eclipse Public License v1.0
6 * which accompanies this distribution, and is available at
7 * http://www.eclipse.org/legal/epl-v10.html
10 * VTT Technical Research Centre of Finland - initial API and implementation
11 *******************************************************************************/
12 package org.simantics.db.common.procedure.single;
14 import java.util.HashSet;
17 import org.simantics.db.procedure.Listener;
19 abstract public class StagedSingleSetListener<T> implements Listener<Set<T>>{
21 private Set<T> previous = null;
23 public void start(Set<T> items) {}
24 public void add(T item) {}
25 public void remove(T item) {}
28 public synchronized void execute(final Set<T> result) {
30 if(previous == null) {
36 HashSet<T> added = new HashSet<T>(result);
37 added.removeAll(previous);
38 HashSet<T> removed = new HashSet<T>(previous);
39 removed.removeAll(result);
41 for(T t : added) add(t);
42 for(T t : removed) remove(t);