1 /*
2 * This file is part of *** M y C o R e ***
3 * See http://www.mycore.de/ for details.
4 *
5 * MyCoRe is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, either version 3 of the License, or
8 * (at your option) any later version.
9 *
10 * MyCoRe is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with MyCoRe. If not, see <http://www.gnu.org/licenses/>.
17 */
18
19 package org.mycore.datamodel.common;
20
21 import org.mycore.common.content.MCRJDOMContent;
22 import org.mycore.common.xml.MCRXMLParserFactory;
23 import org.mycore.datamodel.metadata.MCRMetaElement;
24 import org.mycore.datamodel.metadata.MCRMetaInterface;
25 import org.mycore.datamodel.metadata.MCRObject;
26 import org.mycore.datamodel.metadata.MCRObjectMetadata;
27
28 /**
29 * Helper class to merge mycore objects. Only metadata merging is
30 * currently supported.
31 *
32 * @author Matthias Eichner
33 */
34 public class MCRObjectMerger {
35
36 protected MCRObject target;
37
38 /**
39 * Creates a new instance of the object merger. The target will be cloned for
40 * further processing. You will receive a copy when calling {@link #get()}.
41 *
42 * @param target the target mycore object
43 */
44 public MCRObjectMerger(MCRObject target) {
45 this.target = new MCRObject(target.createXML());
46 }
47
48 /**
49 * Merges the metadata of the given source into the target object. Be aware that
50 * performance isn't that good when validation is activated, due checking against
51 * the schema each time a change is made.
52 *
53 * @param source the source which is merged into the target
54 * @param validate If true, every change is tracked and validated against the
55 * xml schema of the mycore object. When a change is invalid it will be
56 * canceled and the merging continues.
57 * When set to false the mycore object will be merged without validation.
58 * This can result in an invalid object.
59 *
60 * @return true if something was merged
61 */
62 public boolean mergeMetadata(MCRObject source, boolean validate) {
63 MCRObjectMetadata targetMetadata = this.target.getMetadata();
64 boolean merged = false;
65 for (MCRMetaElement metaElementSource : source.getMetadata()) {
66 MCRMetaElement metaElementTarget = targetMetadata.getMetadataElement(metaElementSource.getTag());
67 if (metaElementTarget == null) {
68 targetMetadata.setMetadataElement(metaElementSource.clone());
69 if (validate && !validate(this.target)) {
70 targetMetadata.removeMetadataElement(metaElementSource.getTag());
71 } else {
72 merged = true;
73 }
74 } else {
75 for (MCRMetaInterface metaInterfaceSource : metaElementSource) {
76 boolean equal = false;
77 for (MCRMetaInterface metaInterfaceTarget : metaElementTarget) {
78 if (metaInterfaceSource.equals(metaInterfaceTarget)) {
79 equal = true;
80 break;
81 }
82 }
83 if (!equal) {
84 metaElementTarget.addMetaObject(metaInterfaceSource.clone());
85 if (validate && !validate(this.target)) {
86 metaElementTarget.removeMetaObject(metaInterfaceSource);
87 } else {
88 merged = true;
89 }
90 }
91 }
92 }
93 }
94 return merged;
95 }
96
97 /**
98 * Validates the given mcr object against its own schema.
99 *
100 * @param mcrobj the object to validate
101 * @return true if the object is valid, otherwise false
102 */
103 protected boolean validate(MCRObject mcrobj) {
104 try {
105 MCRXMLParserFactory.getParser(true, true).parseXML(new MCRJDOMContent(mcrobj.createXML()));
106 return true;
107 } catch (Exception exc) {
108 return false;
109 }
110 }
111
112 /**
113 * Returns a copy of the merged target object.
114 *
115 */
116 public MCRObject get() {
117 return this.target;
118 }
119
120 }