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1
5
6 package org.joseki.server.processors;
7
8 import org.joseki.server.*;
9 import org.apache.commons.logging.* ;
10 import java.util.* ;
11
12 import com.hp.hpl.jena.rdf.model.*;
13 import com.hp.hpl.jena.shared.* ;
14 import com.hp.hpl.jena.vocabulary.* ;
15 import org.joseki.server.processors.fetch.* ;
16 import org.joseki.vocabulary.*;
17 import org.joseki.server.module.*;
18 import org.joseki.util.PrintUtils;
19
20
29 public class QueryProcessorFetch extends QueryProcessorCom
30 {
31 Log log = LogFactory.getLog(QueryProcessorFetch.class.getName() ) ;
32
33 public QueryProcessorFetch()
34 {
35 super() ;
36 }
37
38 Resource rdfType = null ;
40 Set fetchHandlers = new HashSet() ;
41
42 public void init(Resource processor, Resource implmentation)
43 {
44 try {
45 StmtIterator sIter = processor.listProperties(JosekiModule.module) ;
47 for ( ; sIter.hasNext() ; )
48 {
49 Statement stmt = sIter.nextStatement() ;
50 Resource fetchBinding = stmt.getResource() ;
51 Loader loader = new Loader() ;
52 FetchHandler handler = (FetchHandler)loader.loadAndInstantiate(fetchBinding, FetchHandler.class) ;
53 log.info(" Fetch: "+handler.getClass().getName()) ;
54
55 String  n1 = handler.getClass().getName() ;
57 for ( Iterator iter = fetchHandlers.iterator() ; iter.hasNext() ; )
58 {
59 FetchHandler handler2 = (FetchHandler)iter.next() ;
60 String n2 = handler2.getClass().getName() ;
61 if ( n1.equals(n2) )
62 log.warn(" Two handlersa of teh same class name: "+n1) ;
63 }
64 fetchHandlers.add(handler) ;
66 }
67
68 } catch (JenaException ex)
69 {
70 log.warn("Exception loading fetch handlers: "+ex) ;
71 return ;
72 }
73
74 if ( implmentation.hasProperty(RDFS.label))
75 log.info("rdfs:label(binding): "+implmentation.getProperty(RDFS.label).getString()) ;
76 if ( processor.hasProperty(RDFS.label))
77 log.info("rdfs:label(processor): "+processor.getProperty(RDFS.label).getString()) ;
78 }
79
80 public String getInterfaceURI() { return JosekiVocab.queryOperationFetch ; }
81
82 public Model execQuery(ModelSource src, String queryString, Request request)
83 throws RDFException, QueryExecutionException
84 {
85 if (!(src instanceof ModelSourceJena))
86 throw new QueryExecutionException(
87 ExecutionError.rcOperationNotSupported,
88 "Wrong implementation - this Fetch processor works with Jena models");
89 Model model = ((ModelSourceJena)src).getModel() ;
90
91 Model resultModel = ModelFactory.createDefaultModel() ;
92 resultModel.setNsPrefixes(model) ;
93 Map m = src.getPrefixes() ;
94 if ( m!= null )
95 resultModel.setNsPrefixes(src.getPrefixes()) ;
96
97 String uri = request.getParam("r") ;
98
99 if (uri != null )
100 {
101 Resource r = model.createResource(uri) ;
102 log.debug("Fetch: "+uri) ;
103 doOneResource(r, resultModel) ;
104 return resultModel ;
105 }
106
107
109 String pURI = request.getParam("p") ;
111 if ( pURI == null )
112 throw new QueryExecutionException(
113 ExecutionError.rcArgumentError,
114 "Fetch must have either resource URI parameter or identifying predicate");
115 Property p = model.createProperty(pURI) ;
116 RDFNode o = null ;
117 String objURI = request.getParam("o") ;
118 if ( objURI == null )
119 {
120 String objVal = request.getParam("v") ;
121 o = model.createLiteral(objVal) ;
122 log.debug("Fetch: p="+pURI+" v="+o) ;
123 }
124 else
125 {
126 log.debug("Fetch: p="+pURI+" o="+objURI) ;
127 o = model.createResource(objURI) ;
128 }
129
130 StmtIterator sIter = model.listStatements(null, p, o) ;
131 if ( ! sIter.hasNext() )
132 return resultModel;
133
134 for ( ; sIter.hasNext() ; )
135 {
136 Resource r = sIter.nextStatement().getSubject() ;
137 doOneResource(r, resultModel) ;
138 }
139 sIter.close() ;
140 return resultModel ;
141 }
142
143 public Model execQuery(ModelSource aModel, Model queryModel, Request request)
144 throws RDFException, QueryExecutionException
145 {
146 throw new QueryExecutionException(ExecutionError.rcOperationNotSupported,
147 "Can't 'fetch' this way") ;
148 }
149
150 private void doOneResource(Resource resource, Model resultModel)
151 {
152 log.debug("Fetch: "+PrintUtils.fmt(resource)) ;
153 Set types = new HashSet() ;
156 StmtIterator sIter = resource.listProperties(RDF.type) ;
157 for ( ; sIter.hasNext() ;)
158 {
159 Resource type = sIter.nextStatement().getResource() ;
161 types.add(type) ;
162 }
163
164 for ( Iterator iter = fetchHandlers.iterator() ; iter.hasNext() ; )
165 {
166 FetchHandler fetch = (FetchHandler)iter.next() ;
167 if ( fetch.handles(resource, types) )
168 fetch.fetch(resource, types, resultModel) ;
169 }
170 }
171
172 }
173
174
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