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/Users/lyon/j4p/src/xml/ModifXmlPrices.java
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1 /**
2 * ModifXmlPrices.java
3 * @author Thomas Rowland
4 * @version 02-08-03
5 */
6
7 package xml;
8
9 import futils.Futil;
10 import org.w3c.dom.*;
11 import org.xml.sax.ErrorHandler;
12 import org.xml.sax.SAXException;
13 import org.xml.sax.SAXParseException;
14
15 import javax.xml.parsers.DocumentBuilder;
16 import javax.xml.parsers.DocumentBuilderFactory;
17 import javax.xml.parsers.ParserConfigurationException;
18 import java.io.*;
19
20 // for SAX exceptions
21
22
23 /*
24 * DomParser program for Product.xml.
25 * This program parses the XML file, increases
26 * the <UnitPrice> element values for each <Product>, and
27 * writes the modified XML out to a new file "NewProduct.xml".
28 * This program uses the DOM Level 2 api and JAXP 1.2.
29 */
30
31 public class ModifXmlPrices {
32 // Node type constants
33 static final int ELEMENT_NODE = 1;
34 static final int TEXT_NODE = 3;
35 static final int DOCUMENT_NODE = 9;
36
37 static float incr = 0;
38 static BufferedWriter out = null;
39
40 public static void main(String[] args)
41 throws IOException {
42 System.out.println("Enter percent price increase: ");
43 BufferedReader in = new BufferedReader(
44 new InputStreamReader(System.in));
45 incr = new Float(in.readLine()).floatValue() * .01f;
46
47 File inFile = Futil.getReadFile("select an XML file");
48 File outFile = new File(inFile.getParent() + "\\NewProduct.xml");
49 out = new BufferedWriter(new FileWriter(outFile));
50
51 parse("file:" + inFile.getAbsolutePath());
52 out.flush();
53 out.close();
54 }
55
56
57 /**
58 * Parses an xml file
59 */
60 private static void parse(String uri)
61 throws IOException {
62
63 // First get the factory
64 DocumentBuilderFactory dbf =
65 DocumentBuilderFactory.newInstance();
66 try {
67 //dbf.setValidating(true);
68
69 // Get the DocumentBuilder
70 DocumentBuilder db = dbf.newDocumentBuilder();
71
72 // Set an error handler
73 db.setErrorHandler(new MyErrorHandler());
74
75 // Parse the file and get back a DOM Document
76 Document doc = db.parse(uri);
77
78 // Get the root element from the DOM Document
79 Element root = doc.getDocumentElement();
80
81 // Now we can traverse the Document and print out results
82 traverse(root);
83 printNode(doc);
84 } catch (ParserConfigurationException e) {
85 // Factory unable to create parser.
86 System.out.println(
87 "** ParserConfigurationException\n"
88 + e.getMessage());
89 } catch (SAXException e) {
90 // Parsing error.
91 System.out.println(
92 "** SAXException\n"
93 + e.getMessage());
94 // Get wrapped exception
95 Exception ex = e.getException();
96 if (ex != null)
97 ex.printStackTrace();
98 } catch (IOException e) {
99 e.printStackTrace();
100 }
101 }
102
103
104 /**
105 * Recursive method which traverses an Element
106 * and searches for the <UnitPrice> element.
107 */
108 private static void traverse(Node elem) {
109 try {
110 if (elem.hasChildNodes()) {
111 NodeList children = elem.getChildNodes();
112 int length = children.getLength();
113
114 for (int i = 0; i < length; i++) {
115 Node n = children.item(i);
116 String name = n.getNodeName();
117
118 if (n.getNodeType() == ELEMENT_NODE) {
119 traverse(n); //recurse
120 } else if (n.getNodeType() == TEXT_NODE) {
121 String pname = n.getParentNode().getNodeName();
122 if (pname.equals("UnitPrice")) {
123 String price = n.getNodeValue();
124 System.out.println(pname + " = " + price);
125 float f = (new Float(price).floatValue()) * (1 + incr);
126 int newPrice = new Float(f).intValue();
127
128 n.setNodeValue(String.valueOf(newPrice));
129 System.out.println("new value of " + pname +
130 " = " + n.getNodeValue() + "\n");
131 return;
132 }
133 }
134 }
135 return;
136 }
137 } catch (DOMException e) {
138 System.out.println("*** DOMException\n"
139 + e.getMessage());
140 }
141 }
142
143
144 /*
145 * Recursive method which prints out a DOM element
146 */
147 private static void printNode(Node node)
148 throws IOException {
149 switch (node.getNodeType()) {
150 case Node.DOCUMENT_NODE:
151 out.write("<?xml version=\"1.0\" encoding=\"ISO-8859-1\""
152 + "standalone=\"yes\"?>\n\n");
153
154 Document doc = (Document) node;
155
156 out.write("<!DOCTYPE "
157 + doc.getDocumentElement().getNodeName()
158 + " [" + doc.getDoctype().getInternalSubset()
159 + "]>\n");
160
161 // recurse on each child
162 NodeList nodes = node.getChildNodes();
163 if (nodes != null) {
164 for (int i = 0; i < nodes.getLength(); i++) {
165 printNode(nodes.item(i));
166 }
167 }
168 break;
169
170 case Node.ELEMENT_NODE:
171 String name = node.getNodeName();
172 out.write("<" + name);
173 NamedNodeMap attributes = node.getAttributes();
174 for (int i = 0; i < attributes.getLength(); i++) {
175 Node attr = attributes.item(i);
176 out.write(" " + attr.getNodeName() +
177 "=\"" + attr.getNodeValue() +
178 "\"");
179 out.newLine();
180 }
181
182 out.write(">");
183
184 // recurse on each child
185 NodeList children = node.getChildNodes();
186
187 if (children != null) {
188 for (int i = 0; i < children.getLength(); i++)
189 printNode(children.item(i));
190 }
191
192 out.write("</" + name + ">");
193
194 case Node.TEXT_NODE:
195 String val = node.getNodeValue();
196 if (val != null)
197 out.write(val);
198 break;
199 }
200 }
201
202
203 /*
204 * Error Handler to report validation errors and warnings.
205 */
206 private static class MyErrorHandler implements ErrorHandler {
207
208 /*
209 * Returns a string describing parse exception details
210 */
211 private String getParseExceptionInfo(SAXParseException spe) {
212 String systemId = spe.getSystemId();
213 if (systemId == null) {
214 systemId = "null";
215 }
216 String info = "URI=" + systemId +
217 "\nLine=" + spe.getLineNumber() +
218 "\n" + spe.getMessage();
219 return info;
220 }
221
222 /*
223 * The following methods are standard SAX ErrorHandler
224 * methods used by DOM
225 */
226 public void warning(SAXParseException spe) throws SAXException {
227 System.out.println("Warning: " + getParseExceptionInfo(spe));
228 }
229
230 public void error(SAXParseException spe) throws SAXException {
231 String message = "Error: " + getParseExceptionInfo(spe);
232 throw new SAXException(message);
233 }
234
235 public void fatalError(SAXParseException spe) throws SAXException {
236 String message = "Fatal Error: " + getParseExceptionInfo(spe);
237 throw new SAXException(message);
238 }
239 }//
240
241 }//