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62 package org.jaxen.function;
63
64 import java.util.Iterator;
65 import java.util.List;
66
67 import javax.xml.parsers.DocumentBuilder;
68 import javax.xml.parsers.DocumentBuilderFactory;
69 import javax.xml.parsers.ParserConfigurationException;
70
71 import junit.framework.TestCase;
72
73 import org.jaxen.*;
74 import org.jaxen.dom.DOMXPath;
75 import org.w3c.dom.Document;
76
77 /***
78 * @author Elliotte Rusty Harold
79 *
80 */
81 public class ExtensionFunctionTest extends TestCase {
82
83 private Document doc;
84
85 public void setUp() throws ParserConfigurationException
86 {
87 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
88 factory.setNamespaceAware(true);
89 DocumentBuilder builder = factory.newDocumentBuilder();
90 doc = builder.newDocument();
91 }
92
93
94 public ExtensionFunctionTest(String name) {
95 super(name);
96 }
97
98 class MinFunction implements Function {
99
100 public Object call(Context context, List args) {
101
102 if (args.isEmpty()) return new Double(Double.NaN);
103
104 Navigator navigator = context.getNavigator();
105 double min = Double.MAX_VALUE;
106 Iterator iterator = args.iterator();
107 while (iterator.hasNext()) {
108 double next = NumberFunction.evaluate(iterator.next(), navigator).doubleValue();
109 min = Math.min(min, next);
110 }
111 return new Double(min);
112 }
113
114 }
115
116
117 public void testRegisterExtensionFunction() throws JaxenException {
118
119 SimpleFunctionContext fc = new XPathFunctionContext(false);
120 fc.registerFunction("http://exslt.org/math", "min", new MinFunction());
121
122 SimpleNamespaceContext nc = new SimpleNamespaceContext();
123 nc.addNamespace("math", "http://exslt.org/math");
124
125 BaseXPath xpath = new DOMXPath("math:min(//x)");
126
127 xpath.setFunctionContext(fc);
128 xpath.setNamespaceContext(nc);
129
130 org.w3c.dom.Element a = doc.createElementNS("", "a");
131 org.w3c.dom.Element b = doc.createElementNS("", "b");
132 doc.appendChild(a);
133 a.appendChild(b);
134 org.w3c.dom.Element x2 = doc.createElementNS("", "x");
135 org.w3c.dom.Element x3 = doc.createElementNS("", "x");
136 org.w3c.dom.Element x4 = doc.createElementNS("", "x");
137 a.appendChild(x4);
138 b.appendChild(x2);
139 b.appendChild(x3);
140 x2.appendChild(doc.createTextNode("2"));
141 x3.appendChild(doc.createTextNode("3"));
142 x4.appendChild(doc.createTextNode("4"));
143
144 Double result = (Double) xpath.evaluate(doc);
145 assertEquals(new Double(2), result);
146
147
148 }
149
150
151 }