Mercurial > dive4elements > river

comparison flys-client/src/main/java/de/intevation/flys/client/server/DistanceInfoServiceImpl.java @ 219:7523faf567e5

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Implemented a service to fetch distance information of a river from the artifact server. flys-client/trunk@1662 c6561f87-3c4e-4783-a992-168aeb5c3f6f
author Ingo Weinzierl <ingo.weinzierl@intevation.de>
date Mon, 11 Apr 2011 14:32:36 +0000
parents
children 924da6695800
comparison
equal deleted inserted replaced
218:79fb4d900643 219:7523faf567e5
1 package de.intevation.flys.client.server;
2
3 import java.util.ArrayList;
4 import java.util.List;
5
6 import javax.xml.xpath.XPathConstants;
7
8 import org.w3c.dom.Document;
9 import org.w3c.dom.Element;
10 import org.w3c.dom.Node;
11 import org.w3c.dom.NodeList;
12
13 import com.google.gwt.user.server.rpc.RemoteServiceServlet;
14
15 import de.intevation.artifacts.common.ArtifactNamespaceContext;
16 import de.intevation.artifacts.common.utils.XMLUtils;
17
18 import de.intevation.artifacts.httpclient.exceptions.ConnectionException;
19 import de.intevation.artifacts.httpclient.http.HttpClient;
20 import de.intevation.artifacts.httpclient.http.HttpClientImpl;
21
22 import de.intevation.flys.client.shared.exceptions.ServerException;
23 import de.intevation.flys.client.client.services.DistanceInfoService;
24 import de.intevation.flys.client.shared.model.DistanceInfoObject;
25 import de.intevation.flys.client.shared.model.DistanceInfoObjectImpl;
26
27
28 /**
29 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
30 */
31 public class DistanceInfoServiceImpl
32 extends RemoteServiceServlet
33 implements DistanceInfoService
34 {
35 public static final String ERROR_NO_DISTANCEINFO_FOUND =
36 "error_no_distanceinfo_found";
37
38 public static final String XPATH_DISTANCES = "art:distances/art:distance";
39
40
41 public DistanceInfoObject[] getDistanceInfo(String url, String river)
42 throws ServerException
43 {
44 System.out.println("DistanceInfoServiceImpl.getDistanceInfo");
45
46 Document doc = XMLUtils.newDocument();
47
48 XMLUtils.ElementCreator ec = new XMLUtils.ElementCreator(
49 doc,
50 ArtifactNamespaceContext.NAMESPACE_URI,
51 ArtifactNamespaceContext.NAMESPACE_PREFIX);
52
53 Element riverEl = ec.create("river");
54
55 riverEl.setTextContent(river);
56
57 doc.appendChild(riverEl);
58
59 HttpClient client = new HttpClientImpl(url);
60
61 try {
62 Document result = client.callService(url, "distanceinfo", doc);
63
64 System.out.println("Extract distance info objects now.");
65 DistanceInfoObject[] objects = extractDistanceInfoObjects(result);
66
67 if (objects != null && objects.length > 0) {
68 return objects;
69 }
70 }
71 catch (ConnectionException ce) {
72 System.err.println(ce.getLocalizedMessage());
73 }
74
75 throw new ServerException(ERROR_NO_DISTANCEINFO_FOUND);
76 }
77
78
79 /**
80 * Extracts all distance info objects from <i>result</i> document.
81 *
82 * @param result The document retrieved by the server.
83 *
84 * @return a list of DistanceInfoObjects.
85 */
86 protected DistanceInfoObject[] extractDistanceInfoObjects(Document result)
87 throws ServerException
88 {
89 NodeList list = (NodeList) XMLUtils.xpath(
90 result,
91 XPATH_DISTANCES,
92 XPathConstants.NODESET,
93 ArtifactNamespaceContext.INSTANCE);
94
95 if (list == null || list.getLength() == 0) {
96 System.err.println("No distance info found.");
97
98 throw new ServerException(ERROR_NO_DISTANCEINFO_FOUND);
99 }
100
101 int num = list.getLength();
102 System.out.println("Response contains " + num + " objects.");
103
104 List<DistanceInfoObject> objects =
105 new ArrayList<DistanceInfoObject>(num);
106
107 for (int i = 0; i < num; i++) {
108 DistanceInfoObject obj = buildDistanceInfoObject(list.item(i));
109
110 if (obj != null) {
111 objects.add(obj);
112 }
113 }
114
115 System.out.println("Retrieved " + objects.size() + " distances.");
116
117 return (DistanceInfoObject[])
118 objects.toArray(new DistanceInfoObject[num]);
119 }
120
121
122 /**
123 * Extracts information for a single distance info object and intializes an
124 * DistanceInfoObject with them.
125 *
126 * @param node The node that contains the information.
127 *
128 * @return a valid DistanceInfoObject.
129 */
130 protected DistanceInfoObject buildDistanceInfoObject(Node node) {
131 String desc = XMLUtils.xpathString(
132 node, "@art:description", ArtifactNamespaceContext.INSTANCE);
133
134 String from = XMLUtils.xpathString(
135 node, "@art:from", ArtifactNamespaceContext.INSTANCE);
136
137 String to = XMLUtils.xpathString(
138 node, "@art:to", ArtifactNamespaceContext.INSTANCE);
139
140 String riverside = XMLUtils.xpathString(
141 node, "@art:riverside", ArtifactNamespaceContext.INSTANCE);
142
143 if (desc != null && from != null) {
144 try {
145 return new DistanceInfoObjectImpl(
146 desc,
147 new Double(from),
148 to != null && to.trim().length() > 0 ? new Double(to) : null,
149 riverside);
150 }
151 catch (NumberFormatException nfe) {
152 System.err.println(nfe.getLocalizedMessage());
153 }
154 }
155
156 System.err.println("Invalid distance info object found.");
157
158 return null;
159 }
160 }
161 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :
http://dive4elements.wald.intevation.org