|
1
17 package org.apache.geronimo.kernel.classloader;
18
19 import java.util.Enumeration  ;
20 import java.util.LinkedList ;
21 import java.util.List ;
22 import java.util.NoSuchElementException ;
23
24
27 public final class UnionEnumeration implements Enumeration {
28 private final LinkedList enumerations = new LinkedList ();
29
30 public UnionEnumeration(List enumerations) {
31 this.enumerations.addAll(enumerations);
32 }
33
34 public UnionEnumeration(Enumeration first, Enumeration second) {
35 if (first == null) throw new NullPointerException ("first is null");
36 if (second == null) throw new NullPointerException ("second is null");
37
38 enumerations.add(first);
39 enumerations.add(second);
40 }
41
42 public boolean hasMoreElements() {
43 while (!enumerations.isEmpty()) {
44 Enumeration enumeration = (Enumeration ) enumerations.getFirst();
45 if (enumeration.hasMoreElements()) {
46 return true;
47 }
48 enumerations.removeFirst();
49 }
50 return false;
51 }
52
53 public Object nextElement() {
54 while (!enumerations.isEmpty()) {
55 Enumeration enumeration = (Enumeration ) enumerations.getFirst();
56 if (enumeration.hasMoreElements()) {
57 return enumeration.nextElement();
58 }
59 enumerations.removeFirst();
60 }
61 throw new NoSuchElementException ();
62 }
63 }
64 |
Popular Tags |
Java API By Example, From Geeks To Geeks.