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