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1
21
22 package nu.xom.samples;
23
24 import java.io.IOException  ;
25 import java.io.InputStream ;
26 import java.io.OutputStream ;
27 import java.math.BigInteger ;
28
29 import javax.servlet.ServletException ;
30 import javax.servlet.SingleThreadModel ;
31 import javax.servlet.http.HttpServlet ;
32 import javax.servlet.http.HttpServletRequest ;
33 import javax.servlet.http.HttpServletResponse ;
34
35 import nu.xom.Builder;
36 import nu.xom.Document;
37 import nu.xom.Element;
38 import nu.xom.Serializer;
39 import nu.xom.XMLException;
40
41
51 public class FibonacciXOMXMLRPCServlet extends HttpServlet
52 implements SingleThreadModel {
53
54 public final static int MALFORMED_REQUEST_DOCUMENT = 1;
56 public final static int INVALID_REQUEST_DOCUMENT = 2;
57 public final static int INDEX_MISSING = 3;
58 public final static int NON_POSITIVE_INDEX = 4;
59 public final static int BAD_INTEGER_FORMAT = 5;
60 public final static int UNEXPECTED_PROBLEM = 255;
61
62 private transient Builder parser;
63
64 public void init() throws ServletException {
66
67 try {
68 this.parser = new Builder();
69 }
70 catch (Exception ex) {
71 throw new ServletException (
72 "Could not locate a JAXP parser", ex);
73 }
74
75 }
76
77 public void doPost(HttpServletRequest servletRequest,
79 HttpServletResponse servletResponse)
80 throws ServletException , IOException {
81
82 servletResponse.setContentType("application/xml; charset=UTF-8");
83 OutputStream out = servletResponse.getOutputStream();
84 InputStream in = servletRequest.getInputStream();
85
86 Document request;
87 Document response;
88 try {
89 request = parser.build(in);
90 Element methodCall = request.getRootElement();
91 Element params = methodCall.getFirstChildElement("params");
92 String generations = params.getValue().trim();
93 int numberOfGenerations = Integer.parseInt(generations);
94 BigInteger result = calculateFibonacci(numberOfGenerations);
95 response = makeResponseDocument(result);
96 }
97 catch (XMLException ex) {
98 response = makeFaultDocument(MALFORMED_REQUEST_DOCUMENT, ex.getMessage());
99 }
100 catch (NullPointerException ex) {
101 response = makeFaultDocument(INDEX_MISSING, ex.getMessage());
102 }
103 catch (NumberFormatException ex) {
104 response = makeFaultDocument(BAD_INTEGER_FORMAT, ex.getMessage());
105 }
106 catch (Exception ex) {
107 response = makeFaultDocument(UNEXPECTED_PROBLEM, ex.getMessage());
108 }
109
110 try {
112 Serializer output = new Serializer(out, "US-ASCII");
113 output.write(response);
114 servletResponse.flushBuffer();
115 out.flush();
116 }
117 catch (Exception ex) {
118 throw new ServletException (ex);
121 }
122
123 }
124
125 public Document makeResponseDocument(BigInteger result) {
130
131 Element methodResponse = new Element("methodResponse");
132 Element params = new Element("params");
133 Element param = new Element("param");
134 Element value = new Element("value");
135 Element doubleElement = new Element("double");
136
137 methodResponse.appendChild(params);
138 params.appendChild(param);
139 param.appendChild(value);
140 value.appendChild(doubleElement);
141 doubleElement.appendChild(result.toString());
142
143 return new Document(methodResponse);
144
145 }
146
147 public Document makeFaultDocument(int faultCode, String faultString) {
148
149 Element methodResponse = new Element("methodResponse");
150
151 Element fault = new Element("fault");
152 Element value = new Element("value");
153 Element struct = new Element("struct");
154 Element memberCode = new Element("member");
155 Element nameCode = new Element("name");
156 Element valueCode = new Element("value");
157 Element intCode = new Element("int");
158 Element memberString = new Element("member");
159 Element valueString = new Element("value");
160 Element stringString = new Element("string");
161
162 methodResponse.appendChild(fault);
163 fault.appendChild(value);
164 value.appendChild(struct);
165 struct.appendChild(memberCode);
166 struct.appendChild(memberString);
167 memberCode.appendChild(nameCode);
168 memberCode.appendChild(valueCode);
169 memberString.appendChild("name");
170 memberString.appendChild(valueString);
171 nameCode.appendChild("faultCode");
172 valueCode.appendChild(intCode);
173 valueString.appendChild(stringString);
174 intCode.appendChild(String.valueOf(faultCode));
175 stringString.appendChild(faultString);
176
177 Document faultDoc = new Document(methodResponse);
178
179 return faultDoc;
180
181 }
182
183 public static BigInteger calculateFibonacci(int generations)
184 throws IndexOutOfBoundsException {
185
186 if (generations < 1) {
187 throw new IndexOutOfBoundsException (
188 "Fibonacci numbers are not defined for " + generations
189 + "or any other number less than one.");
190 }
191 BigInteger low = BigInteger.ONE;
192 BigInteger high = BigInteger.ONE;
193 for (int i = 2; i <= generations; i++) {
194 BigInteger temp = high;
195 high = high.add(low);
196 low = temp;
197 }
198 return low;
199
200 }
201
202 }
203 |
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