1 /**
2 * Copyright 2005-2012 The Kuali Foundation
3 *
4 * Licensed under the Educational Community License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.opensource.org/licenses/ecl2.php
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package org.kuali.rice.krad.util;
17
18 import java.util.Iterator;
19
20 import org.apache.commons.collections.IteratorUtils;
21
22 /**
23 * This class provides utility methods to support the operation of transactional services
24 */
25 public final class TransactionalServiceUtils {
26
27 private TransactionalServiceUtils() {
28 throw new UnsupportedOperationException("do not call");
29 }
30 /**
31 * Copys iterators so that they may be used outside of this class. Often, the DAO may
32 * return iterators that may not be used outside of this class because the transaction/
33 * connection may be automatically closed by Spring.
34 *
35 * This method copies all of the elements in the OJB backed iterators into list-based iterators
36 * by placing the returned BOs into a list
37 *
38 * @param iter an OJB backed iterator to copy
39 * @return an Iterator that may be used outside of this class
40 */
41 public static <E> Iterator<E> copyToExternallyUsuableIterator(Iterator<E> iter) {
42 return IteratorUtils.toList(iter).iterator();
43 }
44
45 /**
46 * Returns the first element and exhausts an iterator
47 *
48 * @param <E> the type of elements in the iterator
49 * @param iterator the iterator to exhaust
50 * @return the first element of the iterator; null if the iterator's empty
51 */
52 public static <E> E retrieveFirstAndExhaustIterator(Iterator<E> iterator) {
53 E returnVal = null;
54 if (iterator.hasNext()) {
55 returnVal = iterator.next();
56 }
57 exhaustIterator(iterator);
58 return returnVal;
59 }
60
61 /**
62 * Exhausts (i.e. complete iterates through) an iterator
63 *
64 * @param iterator
65 */
66 public static void exhaustIterator(Iterator<?> iterator) {
67 while (iterator.hasNext()) {
68 iterator.next();
69 }
70 }
71 }