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.common.xml;
20
21 import org.jdom2.Attribute;
22 import org.jdom2.Document;
23 import org.jdom2.Element;
24 import org.jdom2.Namespace;
25 import org.jdom2.Parent;
26 import org.mycore.common.MCRConstants;
27
28 import java.util.List;
29
30 /**
31 * Builds an absolute XPath expression for a given element or attribute within a JDOM XML structure.
32 *
33 * @author Frank L\u00FCtzenkirchen
34 */
35 public class MCRXPathBuilder {
36
37 /**
38 * Builds an absolute XPath expression for a given element or attribute within a JDOM XML structure.
39 * For each element that is not the root element, the XPath will also contain a position predicate.
40 * For all namespaces commonly used in MyCoRe, their namespace prefixes will be used.
41 *
42 * @param object a JDOM element or attribute
43 * @return absolute XPath of that object. In case there is a root Document, it will begin with a "/".
44 */
45 public static String buildXPath(Object object) {
46 if (object instanceof Element) {
47 return buildXPath((Element) object);
48 } else if (object instanceof Attribute) {
49 return buildXPath((Attribute) object);
50 } else {
51 return "";
52 }
53 }
54
55 /**
56 * Builds an absolute XPath expression for the given attribute within a JDOM XML structure.
57 * For each element that is not the root element, the XPath will also contain a position predicate.
58 * For all namespaces commonly used in MyCoRe, their namespace prefixes will be used.
59 *
60 * @param attribute a JDOM attribute
61 * @return absolute XPath of that attribute. In case there is a root Document, it will begin with a "/".
62 */
63 public static String buildXPath(Attribute attribute) {
64 String parentXPath = buildXPath(attribute.getParent());
65 if (!parentXPath.isEmpty()) {
66 parentXPath += "/";
67 }
68 return parentXPath + "@" + attribute.getQualifiedName();
69 }
70
71 /**
72 * Builds an absolute XPath expression for the given element within a JDOM XML structure.
73 * For each element that is not the root element, the XPath will also contain a position predicate.
74 * For all namespaces commonly used in MyCoRe, their namespace prefixes will be used.
75 *
76 * @param element a JDOM element
77 * @return absolute XPath of that element. In case there is a root Document, it will begin with a "/".
78 */
79 public static String buildXPath(Element element) {
80 if (element == null) {
81 return "";
82 }
83
84 String parentXPath = buildXPath(element.getParent());
85 if ((!parentXPath.isEmpty()) || (element.getParent() instanceof Document)) {
86 parentXPath += "/";
87 }
88 return parentXPath + buildChildPath(element);
89 }
90
91 /**
92 * Builds a local XPath fragment as combined namespace prefix, local element name and position predicate
93 */
94 public static String buildChildPath(Element element) {
95 return getNamespacePrefix(element) + element.getName() + buildPositionPredicate(element);
96 }
97
98 /**
99 * Returns the namespace prefix for this element, followed by a ":",
100 * or the empty string if no namespace prefix known.
101 */
102 public static String getNamespacePrefix(Element element) {
103 Namespace nsElement = element.getNamespace();
104 for (Namespace ns : MCRConstants.getStandardNamespaces()) {
105 if (ns.equals(nsElement)) {
106 return ns.getPrefix() + ":";
107 }
108 }
109
110 String prefix = nsElement.getPrefix();
111 if ((prefix != null) && !prefix.isEmpty()) {
112 return prefix + ":";
113 } else {
114 return "";
115 }
116 }
117
118 private static String buildPositionPredicate(Element element) {
119 Parent parent = element.getParent();
120 if ((parent instanceof Document) || (parent == null)) {
121 return "";
122 }
123
124 Element parentElement = (Element) parent;
125 List<Element> siblings = parentElement.getChildren(element.getName(), element.getNamespace());
126 int pos = siblings.indexOf(element) + 1;
127
128 return "[" + pos + "]";
129 }
130 }