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1
6
7 package com.hp.hpl.jena.db.impl;
8
9 import java.sql.PreparedStatement  ;
10 import java.sql.ResultSet ;
11 import java.util.List ;
12
13 import com.hp.hpl.jena.db.GraphRDB;
14 import com.hp.hpl.jena.db.IDBConnection;
15 import com.hp.hpl.jena.graph.*;
16 import com.hp.hpl.jena.graph.query.BufferPipe;
17 import com.hp.hpl.jena.graph.query.Domain;
18 import com.hp.hpl.jena.graph.query.ExpressionSet;
19 import com.hp.hpl.jena.graph.query.Pipe;
20 import com.hp.hpl.jena.graph.query.Stage;
21 import com.hp.hpl.jena.shared.JenaException;
22
23
26
27 public class DBQueryStage extends Stage
28 {
29 protected Graph graph;
30 protected DBQuery compiled;
31
32 public DBQueryStage( GraphRDB graph, SpecializedGraph sg,
33 List varList, List dbPat, ExpressionSet constraints )
34 {
35 this.graph = graph;
36 this.compiled = compile (sg, varList, dbPat, constraints);
37 }
38
39 protected DBQuery compile( SpecializedGraph sg, List varList, List dbPat, ExpressionSet constraints )
40 { return compile( compiler, sg, varList, dbPat, constraints ); }
41
42 protected DBQuery compile( DBQueryStageCompiler compiler, SpecializedGraph sg,
43 List varList, List dbPat, ExpressionSet constraints )
44 {
45 return DBQueryStageCompiler.compile( compiler, (DBQueryHandler) graph.queryHandler(),
46 sg, varList, dbPat, constraints );
47 }
48
49 private static final DBQueryStageCompiler compiler = new DBQueryStageCompiler();
50
51 protected void run(Pipe source, Pipe sink) {
52 PreparedStatement ps = null;
53 Domain current;
54 Domain useme;
55 IDBConnection conn;
56 if ( !compiled.isEmpty ) try {
57 conn = compiled.driver.getConnection();
58 ps = conn.getConnection().prepareStatement(compiled.stmt);
59 } catch (Exception e) {
60 throw new JenaException("Query prepare failed: " + e);
61 }
62
63 if ( ps != null) while (source.hasNext()) {
64 current = source.get();
65 setArgs(current, ps);
66
68 try {
69 ResultSetIterator it = new ResultSetIterator();
70 ps.execute();
71 ResultSet rs = ps.getResultSet();
72 it.reset(rs, ps, null, null);
73 while (it.hasNext()) {
74 useme = current.copy();
75 List row = (List ) it.next();
76 for(int i=0;i<compiled.resList.length;i++) {
77 int j = compiled.resList[i];
78 String o = (String ) row.get(i);
79 Node n = compiled.driver.RDBStringToNode(o);
80 useme.setElement(j,n);
81 }
82 sink.put(useme);
83 }
84 it.close();
85 } catch (Exception e) {
86 throw new JenaException("Query execute failed: " + e);
87 }
88 }
89 if ( ps != null ) try {
90 ps.close();
91 } catch (Exception e) {
92 throw new JenaException("Close on repared stmt failed: " + e);
93 }
94 sink.close();
95 }
96
97 protected void setArgs ( Domain args, PreparedStatement ps ) {
98 int i, ix;
99 String val;
100 Node arg;
101 try {
102 for ( i=0;i<compiled.argCnt;i++) {
103 ix = ((Integer )compiled.argIndex.get(i)).intValue();
104 arg = (Node) args.get(ix);
105 if ( arg == null ) throw new JenaException("Null query argument");
106 val = compiled.driver.nodeToRDBString(arg,false);
107 ps.setString(i+1, val);
108 }
109 } catch (Exception e) {
110 throw new JenaException("Bad query argument: " + e);
111 }
112
113 }
114
115 public Pipe deliver( final Pipe result )
116 {
117 final Pipe stream = previous.deliver( new BufferPipe() );
118 new Thread () { public void run() { DBQueryStage.this.run( stream, result ); } } .start();
119 return result;
120 }
121
122 }
123
124
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