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Java > Open Source Codes > org > apache > cayenne > access > util > IteratedSelectObserver


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19
20
21 package org.apache.cayenne.access.util;
22
23 import java.io.IOException JavaDoc;
24 import java.io.PrintWriter JavaDoc;
25 import java.io.StringWriter JavaDoc;
26 import java.util.List JavaDoc;
27
28 import org.apache.cayenne.CayenneException;
29 import org.apache.cayenne.CayenneRuntimeException;
30 import org.apache.cayenne.access.ResultIterator;
31 import org.apache.cayenne.query.Query;
32
33 /**
34  * OperationObserver that is used to track the execution
35  * of SelectQueries with results returned as ResultIterator.
36  *
37  * @author Andrus Adamchik
38  */
39 public class IteratedSelectObserver extends DefaultOperationObserver {
40     protected ResultIterator resultIterator;
41
42     public boolean isIteratedResult() {
43         return true;
44     }
45
46     public void nextDataRows(Query query, List JavaDoc dataRows) {
47         throw new CayenneRuntimeException("Results unexpectedly returned as list.");
48     }
49
50     public void nextDataRows(Query q, ResultIterator it) {
51         // don't call super - it closes the iterator
52 resultIterator = it;
53     }
54
55     public ResultIterator getResultIterator() throws CayenneException {
56         if (super.hasExceptions()) {
57             StringWriter JavaDoc str = new StringWriter JavaDoc();
58             PrintWriter JavaDoc out = new PrintWriter JavaDoc(str);
59             super.printExceptions(out);
60
61             try {
62                 out.close();
63                 str.close();
64             } catch (IOException JavaDoc ioex) {
65                 // this should never happen
66 }
67
68             throw new CayenneException(
69                 "Error getting ResultIterator: " + str.getBuffer());
70         }
71
72         return resultIterator;
73     }
74
75 }
76
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