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1   /*
2    * Copyright (c) 2007, James Leigh All rights reserved.
3    * 
4    * Redistribution and use in source and binary forms, with or without
5    * modification, are permitted provided that the following conditions are met:
6    * 
7    * - Redistributions of source code must retain the above copyright notice, this
8    *   list of conditions and the following disclaimer.
9    * - Redistributions in binary form must reproduce the above copyright notice,
10   *   this list of conditions and the following disclaimer in the documentation
11   *   and/or other materials provided with the distribution. 
12   * - Neither the name of the openrdf.org nor the names of its contributors may
13   *   be used to endorse or promote products derived from this software without
14   *   specific prior written permission.
15   * 
16   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26   * POSSIBILITY OF SUCH DAMAGE.
27   * 
28   */
29  package org.openrdf.elmo.example.foaf;
30  
31  import java.io.PrintWriter;
32  import java.io.UnsupportedEncodingException;
33  import java.net.URLEncoder;
34  import java.util.Set;
35  
36  import javax.persistence.EntityManager;
37  import javax.persistence.PersistenceContext;
38  import javax.servlet.http.HttpServletRequest;
39  import javax.servlet.http.HttpServletResponse;
40  import javax.xml.namespace.QName;
41  
42  import org.openrdf.concepts.foaf.Person;
43  import org.springframework.transaction.annotation.Transactional;
44  import org.springframework.web.servlet.ModelAndView;
45  import org.springframework.web.servlet.mvc.Controller;
46  
47  /**
48   * Displays a list of friend for a given resource.
49   * 
50   * @author James Leigh
51   * 
52   */
53  @Transactional
54  public class App implements Controller {
55  	private static final long serialVersionUID = 1L;
56  
57  	private static String NS = "http://www.cs.vu.nl/~pmika/socionet#";
58  
59  	@PersistenceContext
60  	private EntityManager manager;
61  
62  	public ModelAndView handleRequest(HttpServletRequest request,
63  			HttpServletResponse response) throws Exception {
64  		String id = request.getParameter("id");
65  		PrintWriter out = response.getWriter();
66  		printPage(id, out);
67  		return null;
68  	}
69  
70  	private void printPage(String id, PrintWriter out) {
71  		out.println("<html><body><form>");
72  		printHeader(out, id);
73  		if (id != null) {
74  			printTable(out, id);
75  		}
76  		out.println("</form></body></html>");
77  	}
78  
79  	private void printHeader(PrintWriter out, String id) {
80  		out.print("<input name='id' size='64' value='");
81  		if (id != null) {
82  			out.print(id);
83  		}
84  		out.println("'/>");
85  		out.println("<button type='submit'>List Friends</button>");
86  	}
87  
88  	private void printTable(PrintWriter out, String id) {
89  		Person person = manager.find(Person.class, new QName(NS, id));
90  		out.print("<h1>");
91  		for (Object name : person.getFoafNames()) {
92  			out.print(name);
93  		}
94  		out.println("</h1>");
95  		printTable(out, person.getFoafKnows());
96  	}
97  
98  	private void printTable(PrintWriter out, Set<Person> friends) {
99  		out.println("<ul>");
100 		for (Person person : friends) {
101 			out.print("<li>");
102 			out.print("<a href='?id=");
103 			try {
104 				String id = person.getQName().getLocalPart();
105 				out.print(URLEncoder.encode(id, "UTF-8"));
106 			} catch (UnsupportedEncodingException e) {
107 				throw new RuntimeException(e);
108 			}
109 			out.print("'>");
110 			for (Object name : person.getFoafNames()) {
111 				out.print(name);
112 			}
113 			out.print("</a>");
114 			out.println("</li>");
115 		}
116 		out.println("</ul>");
117 	}
118 
119 }