1 /***
2 * Copyright 2003-2010 Terracotta, Inc.
3 *
4 * Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
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
17 package net.sf.ehcache.transaction;
18
19 import net.sf.ehcache.Element;
20 import net.sf.ehcache.search.attribute.AttributeExtractor;
21 import net.sf.ehcache.search.attribute.AttributeExtractorException;
22 import net.sf.ehcache.store.compound.ReadWriteCopyStrategy;
23
24 /***
25 * Used to extract a search attribute value from an element in a transactional store.
26 * <p>
27 *
28 * @author Chris Dennis
29 */
30 public class TransactionAwareAttributeExtractor implements AttributeExtractor {
31
32 private final ReadWriteCopyStrategy<Element> copyStrategy;
33 private final AttributeExtractor delegate;
34
35 /***
36 * Creates an attributed delegating to the supplied extractor, via the given copy strategy.
37 *
38 * @param copyStrategy copy strategy used by the transactional store
39 * @param delegate original configured attribute extractor
40 */
41 public TransactionAwareAttributeExtractor(ReadWriteCopyStrategy<Element> copyStrategy, AttributeExtractor delegate) {
42 this.copyStrategy = copyStrategy;
43 this.delegate = delegate;
44 }
45
46 /***
47 * {@inheritDoc}
48 */
49 public Object attributeFor(Element element, String attributeName) throws AttributeExtractorException {
50 Object value = element.getObjectValue();
51 if (value instanceof SoftLock) {
52 throw new AssertionError();
53 } else {
54 return delegate.attributeFor(copyStrategy.copyForRead(element), attributeName);
55 }
56 }
57 }