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1
50 package org.apache.avalon.excalibur.collections;
51
52 import java.util.ArrayList  ;
53 import java.util.Iterator ;
54 import java.util.List ;
55
56
66 public class ListUtils
67 {
68 public static List intersection( final List list1, final List list2 )
69 {
70 final ArrayList result = new ArrayList ();
71 final Iterator iterator = list2.iterator();
72
73 while( iterator.hasNext() )
74 {
75 final Object o = iterator.next();
76
77 if( list1.contains( o ) )
78 {
79 result.add( o );
80 }
81 }
82
83 return result;
84 }
85
86 public static List subtract( final List list1, final List list2 )
87 {
88 final ArrayList result = new ArrayList ( list1 );
89 final Iterator iterator = list2.iterator();
90
91 while( iterator.hasNext() )
92 {
93 result.remove( iterator.next() );
94 }
95
96 return result;
97 }
98
99 public static List sum( final List list1, final List list2 )
100 {
101 return subtract( union( list1, list2 ),
102 intersection( list1, list2 ) );
103 }
104
105 public static List union( final List list1, final List list2 )
106 {
107 final ArrayList result = new ArrayList ( list1 );
108
109 final Iterator iterator = list2.iterator();
110 while( iterator.hasNext() )
111 {
112 final Object o = iterator.next();
113 if( !result.contains( o ) )
114 {
115 result.add( o );
116 }
117 }
118 return result;
119 }
120 }
121 |
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