bundles/org.simantics.utils.datastructures/src/org/simantics/utils/datastructures/SetUnion.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   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
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.utils.datastructures;
  13
  14 import java.util.Collection;
  15 import java.util.Iterator;
  16 import java.util.Set;
  17
  18 public class SetUnion<T> extends ImmutableCollection<T> {
  19
  20     private Set<T> set1;
  21     private Set<T> set2;
  22
  23     public SetUnion(Set<T> set1, Set<T> set2) {
  24         this.set1 = set1;
  25         this.set2 = set2;
  26     }
  27
  28     @Override
  29     public boolean contains(Object o) {
  30         return set1.contains(o) || set2.contains(o);
  31     }
  32
  33     @Override
  34     public boolean containsAll(Collection<?> c) {
  35         for(Object o : c)
  36             if(!contains(o))
  37                 return false;
  38         return true;
  39     }
  40
  41     @Override
  42     public boolean isEmpty() {
  43         return set1.isEmpty() && set2.isEmpty();
  44     }
  45
  46     @Override
  47     public Iterator<T> iterator() {
  48         return new ImmutableIterator<T>() {
  49
  50             int setId = 0;
  51             Iterator<T> it1 = set1.iterator();
  52             Iterator<T> it2 = set2.iterator();
  53             T element = null;
  54
  55             @Override
  56             public boolean hasNext() {
  57                 if(setId == 0) {
  58                     if(it1.hasNext())
  59                         return true;
  60                     else {
  61                         setId = 1;
  62                         return hasNext();
  63                     }
  64                 }
  65                 else {
  66                     if(element != null)
  67                         return true;
  68                     while(it2.hasNext()) {
  69                         element = it2.next();
  70                         if(set1.contains(element))
  71                             element = null;
  72                         else
  73                             return true;
  74                     }
  75                     return false;
  76                 }
  77             }
  78
  79             @Override
  80             public T next() {
  81                 if(setId == 0) {
  82                     if(it1.hasNext())
  83                         return it1.next();
  84                     else {
  85                         setId = 1;
  86                         return next();
  87                     }
  88                 }
  89                 else {
  90                     if(element != null) {
  91                         T ret = element;
  92                         element = null;
  93                         return ret;
  94                     }
  95                     while(it2.hasNext()) {
  96                         T ret = it2.next();
  97                         if(!set1.contains(ret))
  98                             return ret;
  99                     }
 100                     return null;
 101                 }
 102             }
 103
 104         };
 105     }
 106
 107     @Override
 108     public int size() {
 109         int count = set1.size();
 110         for(T o : set2)
 111             if(!set1.contains(o))
 112                 ++count;
 113         return count;
 114     }
 115
 116 }