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org.apache.commons.jelly.xpath.XPathComparator |
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1 | /* |
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2 | * Copyright 2002,2004 The Apache Software Foundation. |
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3 | * |
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4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
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5 | * you may not use this file except in compliance with the License. |
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6 | * You may obtain a copy of the License at |
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7 | * |
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8 | * http://www.apache.org/licenses/LICENSE-2.0 |
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9 | * |
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10 | * Unless required by applicable law or agreed to in writing, software |
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11 | * distributed under the License is distributed on an "AS IS" BASIS, |
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12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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13 | * See the License for the specific language governing permissions and |
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14 | * limitations under the License. |
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15 | */ |
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16 | package org.apache.commons.jelly.xpath; |
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17 | ||
18 | import java.util.Comparator; |
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19 | import java.util.List; |
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20 | ||
21 | import org.apache.commons.jelly.util.NestedRuntimeException; |
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22 | import org.dom4j.Node; |
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23 | import org.jaxen.JaxenException; |
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24 | import org.jaxen.XPath; |
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25 | ||
26 | /** |
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27 | * Compares xml nodes by extracting the value at xpath and |
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28 | * comparing it. |
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29 | * |
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30 | * @author <a href="mailto:jason@jhorman.org">Jason Horman</a> |
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31 | * @version $Id: XPathComparator.java,v 1.4 2004/09/09 12:29:36 dion Exp $ |
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32 | */ |
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33 | ||
34 | public class XPathComparator implements Comparator { |
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35 | ||
36 | /** The xpath to use to extract value from nodes to compare */ |
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37 | 0 | private XPath xpath = null; |
38 | ||
39 | /** Sort descending or ascending */ |
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40 | 0 | private boolean descending = false; |
41 | ||
42 | 0 | public XPathComparator() { |
43 | ||
44 | 0 | } |
45 | ||
46 | 0 | public XPathComparator(XPath xpath, boolean descending) { |
47 | 0 | this.xpath = xpath; |
48 | 0 | this.descending = descending; |
49 | 0 | } |
50 | ||
51 | public void setXpath(XPath xpath) { |
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52 | 0 | this.xpath = xpath; |
53 | 0 | } |
54 | ||
55 | public XPath getXpath() { |
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56 | 0 | return xpath; |
57 | } |
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58 | ||
59 | public void setDescending(boolean descending) { |
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60 | 0 | this.descending = descending; |
61 | 0 | } |
62 | ||
63 | public int compare(Object o1, Object o2) { |
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64 | 0 | return compare((Node)o1, (Node)o2); |
65 | } |
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66 | ||
67 | public int compare(Node n1, Node n2) { |
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68 | try { |
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69 | ||
70 | // apply the xpaths. not using stringValueOf since I don't |
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71 | // want all of the child nodes appended to the strings |
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72 | 0 | Object val1 = xpath.evaluate(n1); |
73 | 0 | Object val2 = xpath.evaluate(n2); |
74 | ||
75 | // return if null |
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76 | 0 | if (val1 == null || val2 == class="keyword">null) { |
77 | 0 | return val1 == null ? (val2 == class="keyword">null ? 1 : -1) : 1; |
78 | } |
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79 | ||
80 | 0 | Comparable c1 = getComparableValue(val1); |
81 | 0 | Comparable c2 = getComparableValue(val2); |
82 | ||
83 | // compare descending or ascending |
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84 | 0 | if (!descending) { |
85 | 0 | return c1.compareTo(c2); |
86 | } else { |
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87 | 0 | return c2.compareTo(c1); |
88 | } |
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89 | ||
90 | } catch (JaxenException e) { |
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91 | ||
92 | 0 | throw new XPathSortException("error sorting nodes", e); |
93 | ||
94 | } |
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95 | } |
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96 | ||
97 | /** |
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98 | * Turns the XPath result value into a Comparable object. |
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99 | */ |
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100 | protected Comparable getComparableValue(Object value) { |
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101 | 0 | if (value instanceof List) { |
102 | 0 | List list = (List) value; |
103 | 0 | if (list.isEmpty()) { |
104 | 0 | value = ""; |
105 | } |
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106 | 0 | value = list.get(0); |
107 | 0 | if (value == null) { |
108 | 0 | value = ""; |
109 | } |
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110 | } |
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111 | 0 | if (value instanceof Comparable) { |
112 | 0 | return (Comparable) value; |
113 | } |
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114 | 0 | else if (value instanceof Node) { |
115 | 0 | Node node = (Node) value; |
116 | 0 | return node.getStringValue(); |
117 | } |
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118 | 0 | return value.toString(); |
119 | } |
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120 | ||
121 | /** |
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122 | * My own runtime exception in case something goes wrong with sort. |
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123 | */ |
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124 | public static class XPathSortException extends NestedRuntimeException { |
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125 | public XPathSortException(String message, Throwable cause) { |
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126 | super(message, cause); |
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127 | } |
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128 | } |
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129 | } |
This report is generated by jcoverage, Maven and Maven JCoverage Plugin. |