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1
5
6 package com.hp.hpl.jena.db.impl;
7
8 import java.util.List  ;
9
10 import com.hp.hpl.jena.graph.*;
11 import com.hp.hpl.jena.graph.query.*;
12 import com.hp.hpl.jena.shared.JenaException;
13 import com.hp.hpl.jena.vocabulary.RDF;
14
15 import java.util.*;
16
17
24 public final class DBQueryStageCompiler
25 {
26
27 public DBQueryStageCompiler()
28 {}
29
30
34 public static DBQuery compile( DBQueryStageCompiler compiler, DBQueryHandler qh, SpecializedGraph sg,
35 List varList, List dbPat, ExpressionSet constraints )
36 {
37 DBQuery query = new DBQuery(sg,varList,qh.queryOnlyStmt,
38 qh.queryOnlyReif,qh.queryFullReif);
39 int j;
40 if ( !query.isEmpty ) {
41 for (int i = 0; i < dbPat.size(); i += 1) {
42 compilePattern (compiler, query, (DBPattern) dbPat.get(i));
43 }
44 compileConstraints (compiler, query, constraints);
45 compileQuery (compiler, query);
46 }
47 return query;
48 }
49
50
51
54
55 private static void compilePattern( DBQueryStageCompiler compiler, DBQuery query,
56 DBPattern dbpat )
57 {
58 Element subj = dbpat.S;
59 Element obj = dbpat.O;
60 Element pred = dbpat.P;
61 String qual = null;
62 int alias = query.aliasCnt;
63
64 if ( query.isReifier ) {
65 boolean newAlias = true;
66 if ( !(pred instanceof Fixed) )
67 throw new JenaException("Reifier predicate not bound");
68 Node p = ((Fixed)pred).asNodeMatch((Domain)null);
69 char reifProp;
70 if ( p.equals(RDF.Nodes.subject) ) reifProp = 'S';
71 else if ( p.equals(RDF.Nodes.predicate) ) reifProp = 'P';
72 else if ( p.equals(RDF.Nodes.object) ) reifProp = 'O';
73 else if ( p.equals(RDF.Nodes.type) ) {
74 reifProp = 'T';
75 }
76 else throw new JenaException("Unexpected reifier predicate");
77 if ( !subj.equals(Element.ANY) ) {
78 if ( query.qryFullReif && (subj instanceof Free) &&
82 query.getBinding(((Free)subj).getListing()).isBoundToCol() ) {
83 alias = (query.getBinding(((Free)subj).getListing())).alias;
84 newAlias = false;
85 } else
86 qual = query.sqlAnd.gen(getQual(query,alias,'N',subj));
87 }
88 qual += query.sqlAnd.gen(getQual(query,alias,reifProp,obj));
89 qual += query.sqlAnd.gen(query.driver.genSQLQualGraphId(alias,query.graphId));
90 if ( newAlias ) query.newAlias();
91
92 } else {
93 qual = query.sqlAnd.gen(getQual(query,alias,'S',subj));
95 qual += query.sqlAnd.gen(getQual(query,alias,'P',pred));
96 qual += query.sqlAnd.gen(getQual(query,alias,'O',obj));
97 qual += query.sqlAnd.gen(query.driver.genSQLQualGraphId(alias,query.graphId));
98 query.newAlias();
99 }
100 query.stmt += qual;
101 }
102
103 private static String getQual(DBQuery query,int alias,char pred, Element spo) {
104 String qual = "";
105 if (spo instanceof Fixed) {
106 Node obj = ((Fixed) spo).asNodeMatch((Domain) null);
107 if ( query.isReifier )
108 qual = query.driver.genSQLReifQualConst(alias,pred,obj);
109 else
110 qual = query.driver.genSQLQualConst(alias,pred,obj);
111 } else if (spo instanceof Free){
112 Free v = (Free) spo;
113 VarDesc bind = query.getBinding(v.getListing());
114 if ( v.isArg() && !bind.isBoundToCol ) {
117 query.argCnt++;
118 query.argType += pred;
119 query.argIndex.add(new Integer (v.getMapping()));
120 qual = query.driver.genSQLQualParam(alias, pred);
121 bind.bindToCol(alias, pred);
122 } else {
123 if (bind.isBoundToCol()) {
124 qual =
125 query.driver.genSQLJoin( bind.alias, bind.column,
126 alias, pred);
127 } else {
128 bind.bindToCol(alias, pred);
130 qual = "";
131 }
132 }
133 } else if ( spo != Element.ANY )
134 throw new JenaException("Invalid Element in qualifier");
135 return qual;
136 }
137
138
141 private static void compileConstraints( DBQueryStageCompiler compiler, DBQuery query,
142 ExpressionSet constraints ) {
143 Iterator it = constraints.iterator();
144 Expression e;
145 while (it.hasNext()) {
146 e = (Expression) it.next();
147 VarDesc bind = query.findBinding(e.getArg(0).getName());
148 if ( bind == null )
149 throw new JenaException("Unbound variable in constraint");
150 String strMat = ((Expression.Fixed)e.getArg(1)).toString();
151 query.stmt += query.sqlAnd.gen(query.driver.genSQLStringMatch(bind.alias,
152 bind.column, e.getFun(), strMat));
153 }
154 }
155
156
157
160 private static void compileQuery( DBQueryStageCompiler compiler, DBQuery query )
161 {
162 int resCnt = query.vars.length - query.argCnt;
164 query.resList = new int[resCnt];
165 query.stmt = query.driver.genSQLSelectStmt(
166 query.driver.genSQLResList(query.resList,query.vars),
167 query.driver.genSQLFromList(query.aliasCnt,query.table),
168 query.stmt);
169 }
170
171 }
172
173
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