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1 package org.jbpm.bpel.exe;
2
3 import java.util.Iterator  ;
4 import java.util.Map ;
5 import java.util.NoSuchElementException ;
6 import java.util.Stack ;
7
8 import org.jbpm.graph.exe.Token;
9
10
14 public abstract class InstanceIterator implements Iterator {
15 private Stack tokensToTraverse = new Stack ();
16 private Object currentInstance;
17 private InstanceFilter filter;
18
19 public InstanceIterator(Token parent, InstanceFilter filter) {
20 Map children = parent.getChildren();
21 if(children != null && !children.isEmpty()) {
22 tokensToTraverse.addAll(children.values());
23 this.filter = filter;
24 findNextInstance();
25 }
26 }
27
28
29 public void remove() {
30 currentInstance = null;
31 findNextInstance();
32 }
33
34
35 public boolean hasNext() {
36 return currentInstance != null;
37 }
38
39
40 public Object next() {
41 if (!hasNext()) {
42 throw new NoSuchElementException ();
43 }
44
45 Object instanceToReturn = currentInstance;
46 findNextInstance();
47 return instanceToReturn;
48 }
49
50 public abstract Object getInstance(Token token);
51
52 private void findNextInstance() {
53 currentInstance = null;
54
55 do {
56 Object anInstance = hasNextToken() ? getInstance(nextToken()) : null;
57 if( anInstance != null && (filter == null || filter.evaluate(anInstance))) {
58 currentInstance = anInstance;
59 }
60 }while( currentInstance == null && hasNextToken() );
61 }
62
63 private boolean hasNextToken() {
64 return !tokensToTraverse.isEmpty();
65 }
66
67 private Token nextToken() {
68 if (!hasNextToken()) {
69 throw new NoSuchElementException ();
70 }
71
72 Token nextVertex = (Token) tokensToTraverse.pop();
73 addChildrenOf(nextVertex);
74 return nextVertex;
75 }
76
77 private void addChildrenOf(Token nextVertex) {
78 Map children = nextVertex.getChildren();
79 if(getInstance(nextVertex) == null && children != null)
80 tokensToTraverse.addAll(children.values());
81 }
82
83 static abstract class InstanceFilter {
84
85 public abstract boolean evaluate(Object instance);
86 }
87 }
88 |
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Java API By Example, From Geeks To Geeks.