| /******************************************************************************* |
| * Copyright (c) 2001, 2007 Oracle 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: |
| * Oracle Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.jst.jsf.common.sets; |
| |
| import java.util.Iterator; |
| import java.util.Set; |
| |
| /** |
| * Generic (unoptimized) utilities for doing set operations. |
| * |
| * <p><b>Provisional API - subject to change</b></p> |
| * |
| * @author cbateman |
| * |
| */ |
| public class AxiomaticSetUtil |
| { |
| /** |
| * Creates the union of firstSet and secondSet in newSet. |
| * @param newSet |
| * @param firstSet |
| * @param secondSet |
| */ |
| public static void union(AxiomaticSet newSet, AxiomaticSet firstSet, AxiomaticSet secondSet) |
| { |
| newSet.addAll(firstSet); |
| newSet.addAll(secondSet); |
| } |
| |
| /** |
| * Creates an intersection of firstSet and secondSet in newSet |
| * @param newSet |
| * @param firstSet |
| * @param secondSet |
| */ |
| public static void intersect(AxiomaticSet newSet, AxiomaticSet firstSet, AxiomaticSet secondSet) |
| { |
| // minor optimization: always iterate through the smaller of the |
| // two sets. This way we iterate through the smallest number |
| // of elements |
| Iterator it = null; |
| Set testSet = null; |
| // if other set smaller, get its iterator |
| if (secondSet.size() < firstSet.size()) |
| { |
| it = secondSet.iterator(); |
| // test set is other set |
| testSet = firstSet; |
| } |
| // first set is smaller or same |
| else |
| { |
| it = firstSet.iterator(); |
| testSet = secondSet; |
| } |
| |
| while (it.hasNext()) |
| { |
| Object member = it.next(); |
| if (testSet.contains(member)) |
| { |
| newSet.add(member); |
| } |
| } |
| } |
| |
| /** |
| * @param firstSet |
| * @param secondSet |
| * @return true firstSet and secondSet have no common elements (their intersection is empty) |
| */ |
| public static boolean isDisjoint(AxiomaticSet firstSet, AxiomaticSet secondSet) |
| { |
| return firstSet.intersect(secondSet).isEmpty(); |
| } |
| |
| /** |
| * @param firstOperand |
| * @param secondOperand |
| * @return the set formed by removing the intersection of firstOperand and secondOperand |
| * from firstOperand, leaving only those elements in firstOperand that are not in secondOperand |
| */ |
| public static AxiomaticSet subtract( |
| AxiomaticSet firstOperand, AxiomaticSet secondOperand) |
| { |
| ConcreteAxiomaticSet relativeComplement = new ConcreteAxiomaticSet(); |
| |
| // iterate through firstOperand and add each element to the result |
| // set that is not in secondOperand |
| for (final Iterator it = firstOperand.iterator(); it.hasNext();) |
| { |
| Object member = it.next(); |
| if (!secondOperand.contains(member)) |
| { |
| relativeComplement.add(member); |
| } |
| } |
| |
| return relativeComplement; |
| } |
| } |