1 /**
2 * This file Copyright (c) 2009-2018 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.module.delta;
35
36 import info.magnolia.cms.util.QueryUtil;
37 import info.magnolia.module.InstallContext;
38
39 import javax.jcr.Node;
40 import javax.jcr.NodeIterator;
41 import javax.jcr.RepositoryException;
42 import javax.jcr.query.Query;
43
44 /**
45 * An abstract task to perform operations on nodes returned by a given query.
46 * Keep in mind that results returned by a query will reflect the current
47 * content of the repository, <strong>NOT of your session</strong>; i.e if a previous task
48 * modified a property, the query might still return the node as if it had
49 * the previous value.
50 * <p>
51 * Because the limitation above can lead to incomplete updates, we encourage usage of the {@link NodeVisitorTask} instead.
52 *
53 * @see NodeVisitorTask
54 */
55 public abstract class QueryTask extends AbstractRepositoryTask {
56
57 private static final String QUERY_SCOPE_WARNING = "%s is a QueryTask. "
58 + "Mind that JCR queries may NOT account for unsaved changes in current session, e.g. from previous update tasks. "
59 + "To avoid incomplete updates, please use a NodeVisitorTask.";
60
61 private final String repositoryName;
62 private final String query;
63
64 public QueryTask(String name, String description, String repositoryName, String query) {
65 super(name, description);
66 this.repositoryName = repositoryName;
67 this.query = query;
68 }
69
70 @Override
71 protected void doExecute(InstallContext installContext) throws RepositoryException, TaskExecutionException {
72 // we really want to guard against unsafe usages of the QueryTask!
73 installContext.warn(String.format(QUERY_SCOPE_WARNING, getClass().getSimpleName()));
74
75 final NodeIterator nodeIterator = QueryUtil.search(repositoryName, query, Query.JCR_SQL2);
76 while (nodeIterator.hasNext()) {
77 operateOnNode(installContext, nodeIterator.nextNode());
78 }
79 }
80
81 protected abstract void operateOnNode(InstallContext installContext, Node node);
82 }